<PAGE>

                                                                   Exhibit 10.23

       PORTIONS OF THIS EXHIBIT HAVE BEEN OMITTED BASED ON A REQUEST FOR
                             CONFIDENTIAL TREATMENT

                                SUPPLY AGREEMENT



                                 Deltagen, Inc.

                                Affymetrix, Inc.




[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.

<PAGE>

                                    CONTENTS

<TABLE>
<S>                                                                           <C>
INTRODUCTION...................................................................3
DEFINITIONS....................................................................3
PROBE ARRAY SUPPLY.............................................................9
AFFYMETRIX PROPRIETARY RIGHTS.................................................15
COMPENSATION..................................................................16
INTELLECTUAL PROPERTY.........................................................22
PROJECT COORDINATION..........................................................25
CONFIDENTIALITY...............................................................26
WARRANTY......................................................................27
INDEMNITY.....................................................................28
TERM AND TERMINATION..........................................................30
MISCELLANEOUS.................................................................30


EXHIBIT A: INITIAL FORECAST...................................................20
EXHIBIT B: SYSTEMS PURCHASES..................................................21
EXHIBIT C: FABRICATION VERIFICATION CRITERIA..................................39
EXHIBIT D: RMA................................................................40
</TABLE>

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.

<PAGE>

                                SUPPLY AGREEMENT

This Supply Agreement ("Agreement") is effective as of July 12, 2000
("Effective Date") between Affymetrix, Inc. ("Affymetrix") a Delaware
corporation having its principal place of business at 3380 Central Expressway,
Santa Clara, California 95051, and Deltagen, Inc. ("Deltagen") a Delaware
corporation having its principal place of business at 1003 Hamilton Avenue,
Menlo Park, CA 94025.

1        INTRODUCTION

1.1      Affymetrix has research, development, and manufacturing capabilities
         and facilities, and has developed certain rights relevant to DNA probe
         array based technology.

1.2      Deltagen has research and development capabilities, and facilities to
         conduct research and development activities for the generation of
         databases useful in life sciences research.

1.3      Affymetrix and Deltagen desire to enter into an agreement whereby
         Affymetrix will supply Deltagen with DNA probe arrays for use in
         Deltagen's development of database products.

1.4      In consideration of the mutual covenants and promises contained in this
         Agreement, Affymetrix and Deltagen agree as follows:

2        DEFINITIONS

2.1      "Affiliate" shall mean any corporation, company, partnership, joint
         venture and/or firm which is controlled by or controls a Party or is
         under common control with a Party, but only for so long as such
         Affiliate remains an Affiliate of a Party, and only if such Affiliate
         is bound by the terms of this Agreement. For purposes of this Section,
         "control" shall mean, in the case of corporations (or equivalents of
         corporations), direct or indirect ownership of at least *** of the
         stock having the right to vote for directors of such corporation or, in
         the case of partnerships, at least *** of the ownership interest in
         such partnership. Each Party shall be liable to the other Party for
         breach of this Agreement by any of such Party's Affiliates, and any
         such breach shall be deemed a breach by such party.

2.2      "Chip Improvement Inventions" shall mean all those inventions,
         excluding background rights therein, that are conceived and first
         reduced to practice by an employee or contractor of Deltagen or its
         Affiliates at any time during the period beginning on the Effective
         Date and ending *** after termination of this

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -3-
<PAGE>

         Agreement directly resulting from such inventor's use of the Probe
         Arrays supplied hereunder and that specifically relate to probe
         array manufacturing techniques, probe array layouts, and/or probe
         array packaging techniques, and/or to software to extract raw data
         from Probe Arrays *** but not including software or techniques or
         methods for ***, *** and/or *** such data. Deltagen and its
         Affiliates, shall have and retain a perpetual, fully-paid,
         nonexclusive, nontransferable (except pursuant to assignment as
         permitted in Section 12.5), nonsublicensable (except as necessary in
         conjunction with the *** as contemplated in this Agreement),
         world-wide license, and ***, if any, shall have a limited,
         nonexclusive, nontransferable, nonsublicensable internal use only
         right (solely to the extent, and for the sole purpose, and limited
         to the duration of, performing such *** for Deltagen), to each such
         Chip Improvement Invention, for any lawful use, which shall survive
         any termination of this Agreement. It is to be understood that
         neither any other inventions made with respect to the use of Probe
         Arrays nor any inventions made independently of the use of Probe
         Arrays provided hereunder (including, without limitation when made
         through the use of Deltagen's or any third party's proprietary
         technology or knowledge or other intellectual property) are Chip
         Improvement Inventions within the meaning of this Agreement. Chip
         Improvement Inventions shall further not include any other
         inventions that are conceived of or reduced to practice by an
         employee, contractor or customer of a Party or its Affiliates
         including, for example, inventions relating in whole or part to gene
         function, pathways interactions or discoveries resulting therefrom,
         expression data or discoveries resulting therefrom, software
         applications or algorithms used for higher level analysis of
         expression data (beyond that listed in the first sentence of this
         Section 2.2 above), targets identified through the use of the Probe
         Arrays, or correlations between genetic sequences and function (all
         of which are acknowledged and agreed to be the confidential
         information of the Party owning or discovering or developing the
         same, subject otherwise to the protections set forth in Section 8 of
         this Agreement.

2.3      "Committee" shall mean the individuals designated by Deltagen and
         Affymetrix to serve on a coordinating committee as outlined in Section
         7.

2.4      "Confidential Information" shall mean all information and materials,
         patentable or otherwise, of a Party disclosed by or on behalf of such
         Party to the other Party and which derive value to a Party from not
         being generally known, including, but not limited to DNA sequences,
         vectors, cells, substances, formulations, techniques, methodology,
         equipment, data, reports, know- how, trade secrets, pre-clinical and
         clinical trials and the results thereof, sources of supply, patent
         positioning, and business plans, including any negative developments.

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -4-
<PAGE>

2.5      "Custom Probe Array" means a custom Probe Array, ***, sold by
         Affymetrix only to Deltagen and/or its Affiliates hereunder.

2.6      "Database" shall mean a collection of Datapoints which is made broadly
         available for license in whole or in part for use to derive additional
         information. A Database shall be considered to have been made "broadly
         available" for purposes of this Agreement if it is made available to
         third parties other than solely as a Service. If a database includes
         both Datapoints and data or information that is not derived directly
         from the use of a Probe Array supplied under this Agreement, then the
         term "Database" as used in this Agreement shall mean only that portion
         thereof which is comprised of Datapoints. In the event that a
         collection of Datapoints is provided on a Service basis and is later
         made broadly available, such collection of Datapoints shall be
         considered a "Service" at the time delivered to a single customer and a
         "Database" from and after the time it is made broadly available.

2.7      "Datapoint" shall mean the data and/or information (such as expression
         levels per Gene) Deltagen or its Affiliates derives directly from use
         of Probe Array(s) supplied under this Agreement which relates to a
         particular Gene represented on such Probe Array(s) and comprising all
         probe pairs on the Probe Array(s) that represent that Gene. ***.

2.8      "Deltagen's Area Of Interest" shall mean the use of Probe Arrays to
         generate gene expression data, for Deltagen's or its Affiliate's
         internal research purposes, Database technology development purposes
         and/or for generating Databases for license, and providing Services, to
         third parties.

2.9      "Demonstration Database" shall mean a Database that (A) omits or has
         disabled substantial functionality and/or features in comparison with
         the corresponding Database standard product and/or contains no more
         than *** Datapoints (as increased proportional to increases after the
         Effective Date in the number of genes in a Probe Array Chipset); (B) is
         used by Deltagen for testing, training, demonstration, promotional,
         marketing or other comparable purposes without charge (excluding
         nominal media charges and Deltagen's normal installation, service
         and/or training fees); and (C) may be used by the recipient for no more
         than *** from receipt. It is understood that Demonstration Databases
         shall not be distributed such that a recipient may assemble multiple
         Demonstration Databases into a Database.

2.10     "Fabrication Verification Criteria" shall mean Affymetrix' then
         current, applicable quality control criteria for Probe Arrays that are
         widely distributed to third parties, which quality control criteria as
         presently constituted have been delivered to Deltagen and which will be
         provided to Deltagen from time to time when a material change is made,
         plus the Specifications, PROVIDED THAT, the Fabrication Verification
         Criteria provided to Deltagen ***. Affymetrix will not

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -5-
<PAGE>

         change the Fabrication Verification Criteria so as to *** to satisfy
         without Deltagen's prior written consent, which shall not be
         unreasonably withheld. Affymetrix' current Fabrication Verification
         Criteria as of the Effective Date is described in Exhibit C and
         includes the following: Detectability = ***, Specificity = ***.

2.11     "Forward Compatibility" shall mean, with respect to the probe pairs
         representing a single gene present on a Probe Array, the preservation
         of the DNA sequences in each and all of such probe pairs between and
         among all other Probe Arrays of the same Probe Array Chipset (including
         subsequent releases and versions of Probe Arrays with different
         specifications, such as an increase in the number or composition of the
         genes comprising the Probe Array Chipset).

2.12     "GATC Compliant" shall mean software and/ or databases meeting the
         standards set forth in accordance with the Genetic Analysis Technology
         Consortium ("GATC") standards group. In the event that the GATC
         standards are no longer maintained, the Parties will negotiate in good
         faith to define substitute specifications for interoperability of their
         respective software and databases.

2.13     "Gene" shall mean a nucleic acid sequence encoding a distinct RNA
         transcript. A Gene may be represented by a partial nucleic acid
         sequence representing an expressed sequence tag (EST). Multiple ESTs
         from the same Gene are considered a single Gene. Polymorphic variants
         of a nucleic acid sequence are considered a single Gene. If a nucleic
         acid sequence encodes multiple distinct RNA transcripts due to
         alternative splicing, each alternative internal splice variant is
         considered a distinct Gene.

2.14     "Lot" shall mean the standard minimum quantities in which Probe Arrays
         are made available to third parties, as set forth in Affymetrix' price
         list and specifications.

2.15     "Net Sales" shall mean the aggregate United States Dollar equivalent of
         gross revenues derived by or payable to Deltagen or its Affiliates for
         the transfer, sale, license, lease or other disposition of
         Databases, or the right to access or use Databases, to third parties
         less a) credits or allowances, if any, actually granted on account
         of price adjustments, recalls, rejections, or return of items
         previously sold, prompt payment discounts, *** actually incurred; b)
         actual trade or quantity discounts actually allowed and taken; c)
         excises, sales taxes, value added taxes, consumption taxes, duties,
         foreign withholding tax actually withheld, or other taxes imposed
         upon and paid with respect to such sales (excluding income or
         franchise taxes of any kind); d) *** insurance, delivery, costs
         actually incurred and e) any *** other payments paid to *** on
         account of *** by, and/or for rights and/or licenses relating to,
         *** or *** or *** and/or their *** as

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -6-
<PAGE>

         contemplated hereby or in their respective *** or other ***. No
         deduction shall be made for any item of cost incurred by Deltagen or
         its Affiliates in preparing, manufacturing, shipping, or selling
         Databases except as permitted pursuant to a), b), c), and d) above
         and the aggregate deductions to Net Sales pursuant to a) above shall
         not exceed ***. Net Sales shall not include (A) any royalties or
         license fees or other payments for (i) licenses under Deltagen's
         patents or other proprietary rights, even if the need for or
         desirability of such license arises out of the use of a Database,
         (ii) any knockout mice, conditional knockout mice, knock-in mice or
         any other animal(s) or any associated sperm, cells, materials or
         tissues, or (iii) licenses or other rights to access or use, or to
         be provided, information or data not directly derived from use of a
         Probe Array, even if such information is also contained within or
         derivable from a Probe Array; (B) any internal use by Deltagen or
         its Affiliates; or (C) any transfer between or among Deltagen and
         any of its Affiliates including if for re-license or resale. If
         Deltagen or an Affiliate licenses or sells to or through a
         distributor (which is not an Affiliate of Deltagen), Net Sales shall
         be the gross revenues (including but not limited to royalties and
         agency fees) received by Deltagen and/ or the applicable Affiliate
         from the license or other transfer of the Database to such
         distributor. In the event that Deltagen or any of its Affiliates
         licenses a Database to third parties for other than monetary value
         in whole or in part, such transfer shall be considered a license
         hereunder for accounting and royalty purposes. In the event cash and
         non-cash consideration or solely non-cash consideration is received
         by Deltagen, Net Sales shall be the cash consideration, if any, plus
         the value of non-cash consideration. Non cash consideration shall be
         determined on a country-by-country basis and shall be the average
         price of comparable arms length licenses solely for cash by Deltagen
         or its Affiliates in such country during the royalty reporting
         period in which such transfer occurs less the amount of cash
         consideration received, if any, or if no such comparable arms length
         licensing occurred in such country during such period, during the
         last period in which such arms length sales occurred. If no arms
         length licenses solely for cash have occurred in a particular
         country, non cash consideration for such transfer shall be the
         average price of comparable arms length licenses solely for cash in
         all countries less the amount of cash consideration received, if
         any. If no comparable arms length licenses solely for cash occurred,
         then the value of non cash consideration shall be valued on an
         equitable basis to be agreed upon by the parties. If a Database is
         sold or licensed as part of a database that includes both Datapoints
         and other information or data and/or as part of a system, package,
         or combination with other product(s), license(s) and/or service(s)
         (collectively, a "Product Bundle"), then the Net Sales attributable
         to the Database for purposes of

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -7-
<PAGE>

         this Agreement shall be calculated by multiplying the Net Sales of the
         Product Bundle during that financial reporting period in question by
         the fraction A/ B where "A" is the average unit price during that
         period of the Database when licensed separately and "B" is the sum of
         all the average unit prices during that period of all of the component
         products and services comprising the Product Bundle when licensed or
         sold separately. If the Database or any other component product or
         service of a Product Bundle is not licensed or sold separately from the
         combination comprising the Product Bundle, then the percentage of the
         Net Sales of the Product Bundle that is attributable to the Database
         shall be an equitable allocation as reasonably determined by the
         Parties (or, if the Parties cannot agree, by arbitration in accordance
         with Section 12.6).

2.16     "Party" shall mean Affymetrix or Deltagen, as the context requires.
         "Parties" shall mean Affymetrix and Deltagen.

2.17     "Physical Defect" shall mean, with respect to a Probe Array, a defect
         in materials or workmanship of such Probe Array, or a defect in such
         Probe array resulting from the manufacture or handling of such Probe
         Array prior to delivery to the common carrier in accordance with
         Section 3.5, such that defect(s) are the cause of impaired
         hybridization of probe pairs, or any other impairment leading to
         materially aberrant Datapoints. Such determination must be made
         pursuant to Affymetrix' then current standard GeneChip expression assay
         protocols and Fabrication Verification Criteria that apply to such
         Probe Arrays.

2.18     "Probe Array" shall mean a solid support having an array of
         polynucleotides with known location and sequence fabricated by
         Affymetrix pursuant to this Agreement for use in expression analysis.

2.19     "Probe Array Chipset" means a set of Probe Arrays representing
         Affymetrix' then-current representation of the genome of a particular
         species or organism.

2.20     "Proprietary Probe Arrays" shall mean Probe Arrays which contain
         substantial proprietary genetic information of a third party for which
         incremental fees are due by Affymetrix to such third party associated
         with the use of such proprietary genetic information.

2.21     "Services" shall mean (i) the "one-off" provision of a custom
         collection of unique (relative to the Database(s) and not just a subset
         thereof) Datapoints for value exclusively to a single third party
         solely for such third party customer's internal use and/or (ii) the
         business of Deltagen using Probe Arrays to generate expression analysis
         information for third party customers on a service bureau basis. The
         term "Service" does not include offering customers the option to
         acquire a subset of the Datapoints that comprise a Database.

2.22     "Software" shall mean the software provided to Deltagen by Affymetrix
         for use with Probe Arrays and Systems.

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -8-
<PAGE>

2.23     "Specifications" shall mean Affymetrix' then-current Probe Array
         specifications, current versions (as of the Effective Date) of which
         will be provided to Deltagen within seven (7) days of the execution of
         this Agreement, for the Probe Arrays provided pursuant to this
         Agreement.

2.24     "System(s)" shall mean fluidics station(s), work station(s), probe
         array reader(s), hybridization ovens and any other systems or equipment
         sold to Deltagen pursuant to this Agreement.

2.25     "Term" shall mean the period beginning on the Effective Date and
         ending on a date (a) one (1) year after the Effective Date in the event
         Deltagen elects option (a) to continue under the terms and
         conditions of the "Beginning Period" as set forth in Section 5.1, in
         which case the Term shall be renewable for successive one (1) year
         periods (each, an "Extended Term") upon mutual written agreement by the
         Parties; or (b) three (3) years from the Effective Date in the event
         Deltagen elects option (b) as set forth in Section 5.1, unless extended
         pursuant to Section 5.1 in which case "Initial Term" shall mean the
         initial 3 year portion of the Term and "Extended Term" shall mean
         the potential extension of the Term by 2 or 4 years pursuant to Section
         5.1.

3        PROBE ARRAY AND SYSTEM SUPPLY

3.1      Only Custom Probe Arrays pursuant to Section 5.12 and those expression
         Probe Arrays listed in Affymetrix' catalog at standard prices will be
         available for purchase pursuant to this Agreement.

3.2      Beginning on the Effective Date, Affymetrix will deliver such
         quantities of the appropriate Probe Arrays meeting the requirements of
         this Agreement, as specified in a properly rendered forecast made
         pursuant to Section 3.4, or, for the first 3 months of the Term,
         according to a forecast previously supplied by Deltagen and attached as
         Exhibit A. All Probe Arrays delivered to Deltagen under this Agreement
         shall have a ***.

3.3      Affymetrix shall maintain a minimum capacity to supply to Deltagen at
         least *** Probe Arrays per month (as used in this Agreement, "month"
         means a calendar month), subject to the next two sentences. In no event
         will Affymetrix be obligated to provide more than *** Probe Arrays in
         any one month (as increased proportional to increases in the number of
         Probe Arrays comprising the Probe Array Chipset(s) purchased by
         Deltagen); provided, however, Affymetrix shall use commercially
         reasonable efforts to fill Deltagen's orders for Probe Arrays in excess
         of said limit. In the event Affymetrix experiences a significant
         decrease in manufacturing yield for a sustained period or other
         manufacturing incapacity (as opposed to intentionally accepting orders
         in excess of Affymetrix's ability to

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -9-
<PAGE>

         timely fill the same), such that Affymetrix is unable to supply
         Deltagen with previously accepted orders of properly forecasted Probe
         Arrays up to the maximum quantity per month obligation set forth in
         Section 3 above ("Qualifying Deltagen Orders"),***.

3.4      Beginning on the Effective Date and on a monthly rolling basis on the
         first business day of each month during the Term of this Agreement,
         Deltagen will provide a reasonable, good faith forecast of Probe Arrays
         to be supplied by Affymetrix during the following *** period or the
         period until the end of the Term if less than *** (such forecasts to be
         supplied by number of Probe Arrays and part number) to Deltagen and its
         Affiliates. The forecast will be provided according to a mechanism and
         on forms consistent with this Agreement and to be agreed upon in good
         faith by the Parties within 30 days after the Effective Date. The first
         and second month of each successive forecast (part number and
         individual quantity) shall constitute a firm order by Deltagen,
         accepted by Affymetrix, for the purchase of Probe Arrays under this
         Agreement. The subsequent months of such forecast will be Deltagen's
         non-binding estimate for capacity planning purposes only, and shall not
         be or constitute a commitment or firm order.

3.4.1    Delivery times for all Probe Arrays ordered hereunder will be on
         date(s), quoted at the time Affymetrix receives a firm order for such
         products, within the month as to which such order relates (subject to
         Sections 3.3 and 3.4 above). If Deltagen requests specific delivery
         date(s) for a firm order, then Affymetrix will use commercially
         reasonable efforts to deliver in accordance with such request.

3.4.2    Unless approved in writing by Deltagen, over-shipment or under-shipment
         of an order in excess of *** shall not be allowed.

3.4.3    If Affymetrix ships an order more than *** or more than ***, then a ***
         shall be applied to such order.

3.4.4    If the number of ordered Probe Arrays for a month increases by more
         than *** from the immediately preceding firm forecast for such month,
         then the number of such Probe Arrays above the *** increase shall be
         supplied in a reasonable time, but shall not be subject to penalty or
         breach on account of late supply thereof for purposes of Section 3.4.3.

3.5      Probe Arrays will be packed in Affymetrix' standard shipping packages
         and shipped to the address specified by Deltagen. Delivery of Probe
         Arrays hereunder will be F. O. B. Affymetrix' facility or the facility
         of its sales representative upon actual delivery to the common carrier
         for shipment to Deltagen. Delivery of Probe Arrays to the common
         carrier will be deemed by the Parties to be a representation by
         Affymetrix that such Probe Arrays have passed Affymetrix' then-current
         standard Probe Array quality control procedures and, meet the
         then-current

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -10-
<PAGE>

         Fabrication Verification Criteria. Affymetrix will ship via a common
         carrier and mode of shipment selected by Deltagen or, if none is
         specified by Deltagen, Affymetrix will select the common carrier and
         mode of shipment. Title and risk of loss or damage for deliveries will
         pass to Deltagen upon delivery at the F. O. B. point. Deltagen will pay
         all shipping costs from the F. O. B. point, duties, and sales taxes.
         Deltagen will advise Affymetrix if insurance is desired on any
         shipments of Probe Arrays, and will reimburse Affymetrix for all such
         insurance charges.

3.6      Subject to provisions herein relating to warranty and support, all
         Probe Arrays will be deemed accepted unless they are returned to
         Affymetrix within 45 days after delivery to Deltagen, with written
         explanation of the basis on which such Probe Arrays have been returned,
         on Affymetrix' standard "Return Materials Authorization" according to
         the procedures provided for in such Return Materials Authorization (a
         current version (as of the Effective Date) of which is set forth in
         Exhibit D). Affymetrix will replace (i) all Probe Arrays that have
         Physical Defects and (ii) the entire affected Lot if more than a
         reasonable number, consistent with Affymetrix' normal quality criteria
         and overall size of the Lot, of the Probe Arrays in that Lot have
         Physical Defects. Replacements of Probe Affrays or Lots pursuant to the
         preceding sentence shall be free of charge to Deltagen and at
         Affymetrix' expense as to both in-bound and out-bound shipping costs.

3.7      Notwithstanding anything to the contrary herein, Affymetrix will
         provide Deltagen, *** in addition to the installation, set up and
         certification activities contemplated by Section 3.13, with (i) up to
         *** qualified instructor-days of training in use of Probe Arrays and
         Systems during the "Beginning Period" (as defined in Section 5.1) and
         up to *** qualified instructor-days of such training per year during
         the remainder of the Term, as requested by Deltagen, in accordance with
         schedules to be mutually and reasonably agreed and (ii) all *** used in
         the course of the standard initial System setup procedure for each
         System installed hereunder. In cases where Deltagen elects to have
         training at Affymetrix' facility, travel and expenses of Deltagen
         personnel will be paid by Deltagen. Additional training will be
         reasonably provided by Affymetrix to Deltagen at the request of
         Deltagen at the then current commercial terms.

3.8      Deltagen may not: 1) transfer the Probe Arrays provided by Affymetrix
         pursuant to this Agreement to third parties other than Deltagen's
         Affiliates and/or research partners who have purchased Affymetrix
         instrumentation systems and have in effect a license from Affymetrix to
         use such systems with Affymetrix probe arrays to perform bona fide
         contract research for the benefit of Deltagen and/or its Affiliates
         (such contract research must be pursuant to a written agreement

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -11-
<PAGE>

         consistent with this Agreement) but only for so long as such license
         remains in effect and such third parties comply with the terms and
         conditions applicable to their use of Affymetrix products ("Research
         Partners"); or 2) transfer the data generated by use of Probe Arrays to
         any third party other than (i) Affiliates, (ii) Research Partners or
         (iii) subscribers to a Database; or 3) use the Probe Arrays provided by
         Affymetrix pursuant to the Agreement to provide services to any third
         party, other than to Affiliates, except as to those Probe Arrays where
         i) the service recipient agrees to limit further distribution of the
         data to other third parties consistent with Affymetrix' normal probe
         array supply terms and conditions as updated from time to time with
         advance written notice to Deltagen (Affymetrix has provided Deltagen
         with a copy of such terms and conditions as in effect as of the
         Effective Date; Deltagen shall use commercially reasonable efforts to
         promptly integrate updates to such terms and conditions not later than
         90 days after Deltagen's receipt thereof, except that unless Deltagen
         elects otherwise, updated terms and conditions shall not apply to any
         binding agreement between Deltagen and the service recipient in
         existence as of the effective date of the update that is consistent
         with the version of such terms and conditions in effect at the time
         such agreement became binding on or the firm commitment of Deltagen),
         and (ii) the applicable fee for Probe Arrays used in Services is paid
         pursuant to Section 5.3; or 4) allow any third party, other than
         Affiliates and Research Partners for use in Deltagen's Area of
         Interest, to use the Probe Arrays supplied by Affymetrix to Deltagen
         under this Agreement; or 5) otherwise use the Probe Arrays delivered
         hereunder outside of Deltagen's Area of Interest; or 6) reuse the Probe
         Arrays; or 7) use Probe Arrays in diagnostic or other similar settings
         requiring FDA or other comparable regulatory agency approval unless
         Deltagen obtains such approval and such Probe Arrays are to be used in
         a clinical trial (and such Probe Arrays are not for microbial or
         pathogenic organisms). Deltagen will allow Affymetrix reasonable,
         periodic (but not more than once per year unless Deltagen has failed to
         comply with the prohibition against reuse) access to the Systems during
         regular business hours and with advance written notice solely to ensure
         compliance with the prohibition against reuse and, in the case of an
         audit conducted by an Affymetrix employee, without access to or
         retention of any expression analysis or other information or data of
         Deltagen or any of its Affiliates and Research Partners or its or their
         customers, licensors or licensees; if Affymetrix utilizes an
         independent auditor, such auditor shall have access to such information
         as reasonably necessary to perform the audit provided that such auditor
         shall not disclose the contents of such information to Affymetrix or
         its Affiliates. Any auditor shall be under reasonable obligations of
         confidentiality.

3.9      All Databases (excluding those provided on a Service basis) transferred
         to a third

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -12-
<PAGE>

         party by Deltagen pursuant to this Agreement will be GATC Compliant ***
         that it is *** to use the GATC standard. Deltagen will bear its
         internal costs of such GATC compliance.

3.10     Deltagen may not sell or license the Databases through a distributor or
         agent except pursuant to written agreement(s) consistent with this
         Agreement.

3.11     Affymetrix will provide to Deltagen all standard System and Probe Array
         information, documentation and manuals and, in any event, sufficient
         genetic information to identify all the Genes on each Probe Array. If
         Affymetrix updates its Probe Arrays to include additional or different
         genetic sequence information, Affymetrix shall provide such information
         to Deltagen promptly, and in any event not later than *** after
         Affymetrix first makes such information *** .

3.12     Upon either Party's request, Deltagen and Affymetrix may reasonably
         cooperate in joint promotional activities of the Databases generated
         hereunder as mutually agreed. Each Party may use the other Party's
         trademarks, logos and tradenames ("Marks")as mutually agreed upon by
         the Parties , provided that the use by a Party of any of the other
         Party's Marks shall be subject to approval by such other Party, which
         approval shall not be unreasonably withheld or delayed. Each Party
         acknowledges the ownership by the other Party of its respective Marks.
         Each Party will maintain a high quality standard in connection with
         products and services promoted in connection with the other Party's
         Marks. If, in either Party's sole discretion, the other Party's use of
         the first Party's Marks does not meet the first Party's trademark usage
         policy as (i) actually complied with by the first Party and (ii) as
         communicated to the second Party in writing, then the first Party may,
         at its option, terminate the second Party's right to use the Marks
         pursuant to this Section 3.11. The parties agree to negotiate in good
         faith joint marketing activities where mutually deemed applicable.

3.13     Deltagen will issue by *** purchase order(s) for the System(s) and
         Software specified on Exhibit B. Promptly upon its receipt of
         Deltagen's purchase order, Affymetrix will *** install and set-up
         (including configuration, testing and certification) the Systems
         ordered hereunder at Deltagen's facility in accordance with Affymetrix'
         standard installation procedures ("Installation"). The Parties will
         cooperate and use all commercially reasonable efforts to complete
         Installation by not later than a date to be mutually agreed upon within
         seven (7) days after execution of this Agreement.

3.14     In the event that Affymetrix makes ***, the Specifications or any other
         material probe array specification(s) such that Deltagen reasonably
         will have to undergo *** or other *** to effectively incorporate
         Datapoints from Probe Arrays incorporating such change into a Database
         or to maintain *** Databases or Datapoints generated before and after
         the change, and Affymetrix provides

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -13-
<PAGE>

         assistance intended to help ameliorate such situation to any other
         of its un-affiliated third party customers, then Affymetrix shall
         offer Deltagen at least the same or materially similar type(s) and
         level(s) of assistance on terms not less favorable, taken as a
         whole, than the most favorable of those offered to such other
         un-affiliated third party customers. Affymetrix shall use its
         commercially reasonable efforts to ensure *** when designing updates
         or changes to Probe Arrays. If Affymetrix is unable to maintain a
         commercially reasonable level of Forward Compatibility in a
         subsequent version of a Probe Array Chipset purchased by Deltagen
         such that Deltagen's ability (and/or associated costs) to generate,
         populate or maintain its expression database products or services
         are materially and adversely affected, then notwithstanding anything
         herein to the contrary, Affymetrix shall *** (subject to the same
         per *** set forth in Section 5) or, alternatively, Deltagen may
         within 60 days of Affymetrix discontinuing of the then previous
         Probe Array Chipset as a standard product offering in its catalogue
         elect to terminate this Agreement on six (6) months prior written
         notice.

4        AFFYMETRIX PROPRIETARY RIGHTS

4.1      Until the end of the Term, Deltagen will not buy probe arrays of
         diverse nucleic acids on solid supports from a third party when such
         third party arrays materially infringes the patent or copyright
         rights (or would materially infringe an allowed but as of then
         unissued patent claim) of Affymetrix or its Affiliates. In order to
         enforce this provision Affymetrix must provide Deltagen a)
         reasonable and prompt written notice of such infringement upon
         Affymetrix becoming aware of such infringement, b) reasonable
         evidence of such infringement, with which counsel for Deltagen
         reasonably concurs, c) reimburses Deltagen for the reasonable costs
         and expenses of counsel incurred in the review contemplated by
         clause b) preceding, and d) agrees in its notice to settle or defend
         any suit or proceeding brought against Deltagen and its affiliates
         to the extent based on a breach of contract or similar claim and to
         pay all damages and costs finally awarded against Deltagen for such
         claim and other reasonable related costs and expenses (including
         reasonable attorneys fees) arising out of Deltagen's compliance with
         this section 4.1. In order to avail itself of the benefits of (c)
         and (d) above, Deltagen shall (i) provide the notice described in
         (a) above to Deltagen's counsel within a reasonable period of time
         after receipt of such notice from Affymetrix (reasonably sufficient
         for (b) above to occur) and prior to entering into any new agreement
         or other binding commitment (ie., an agreement or commitment not
         existing as of the date of Deltagen's receipt of Affymetrix's
         notice) obligating Deltagen to buy any probe arrays of diverse
         nucleic acids on solid supports from a third party where Deltagen
         foresees or could reasonably foresee that such third party arrays
         materially infringe the patent or copyright rights (or would
         materially infringe an allowed but as of then unissued patent claim)
         of Affymetrix or its Affiliates that are described in such notice,
         and (ii) promptly, upon the occurrence of (b) above, cease all
         negotiations and other interactions with such third party with
         respect to such infringing arrays, provided that if (b) above does
         occur, including if Deltagen subsequent to (a) above has entered
         into a new agreement or other binding commitment after having
         allowed reasonably sufficient time for (b) above to occur, then
         Deltagen shall terminate

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -14-
<PAGE>

         such agreement or commitment as soon as contractually and legally
         permissible and use its best efforts to abide by all contractual and
         legal requirements applicable to such termination. This Section 4.1,
         PER se, shall not confer on Deltagen or any third party any rights
         under the patent rights of Affymetrix not already licensed as set forth
         in Section 4.2.

4.2      Affymetrix hereby grants Deltagen and its Affiliates a non-exclusive,
         worldwide right and license, subject to Deltagen and its Affiliates
         compliance with the terms and conditions of this Agreement, to (i) use
         the Software (subject further to Deltagen's compliance with Affymetrix'
         standard software license terms and conditions (in written and/or
         "click-through" form) on the workstation(s) provided with the System(s)
         hereunder in accordance with its documentation and manuals to use and
         operate such System(s) (a copy of such license has been provided to
         Deltagen); (ii) use Probe Arrays, data, information and other materials
         provided by Affymetrix pursuant to this Agreement, derive Datapoints
         and generate Databases and Product Bundles therefrom and provide,
         distribute and sublicense Databases and Services, all subject to, and
         in accordance with, the terms and conditions of this Agreement; and
         (iii) otherwise practice and have the quiet enjoyment of the benefits
         and intents of this Agreement, as set forth herein.

5        COMPENSATION

5.1      Deltagen shall pay to Affymetrix a technology access fee of $500,000
         on the Effective Date which shall cover the period beginning on the
         Effective Date and ending on the whichever of the following occurs
         first: (i) the *** of the Effective Date or (ii) the *** by Deltagen
         of a Database that generates Net Sales (the "Beginning Period").
         Beginning on the last day of the Beginning Period and continuing
         throughout the remainder of the Term (and any Extended Term),
         Deltagen shall have a ***, exercisable by providing written notice
         to Affymetrix thirty (30) days after the first-to-occur date
         described in the first sentence, to either (a) continue under the
         terms and conditions applicable during the Beginning Period
         (including without limitation, training obligations as set forth in
         Section 3.7, Probe Array fees as set forth in Sections 5.2 and 3,
         and Database royalties as set forth in Section 5.5), in which case
         the "Beginning Period" shall be deemed by the Parties to mean, and
         all such terms and conditions shall exclusively apply during, the
         period beginning on the Effective Date and continuing throughout the
         remainder, if any, of the Term and any Extended Term as set forth in
         this Section; or (b) pay Affymetrix a technology access fee of
         $4,000,000 per year according to the following payment schedule:
         1,000,000 within 30 days after the last day of the Beginning Period
         and 1,000,000 at the end of every three (3) month period thereafter
         throughout the remainder of the Term (and

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -15-
<PAGE>

         any Extended Term). In the event Deltagen elects option (b) above,
         Deltagen may extend the Term by two (2) years by providing written
         notice to Affymetrix no later than ninety (90) days before the end of
         the Initial Term. If so extended for two (2) years, Affymetrix will
         negotiate in good faith for an additional extension of the Term of the
         Agreement under similar terms for an additional two (2) years (for a
         potential total Term of up to seven (7) years), provided that Deltagen
         must provide *** before the end of the initial Extended Term of its
         desire to negotiate in good faith for such extension.

5.2      For each expression Probe Array (excluding those Probe Arrays for use
         in internal use or Services) delivered to Deltagen or its Affiliates
         during the Beginning Period that meet the Fabrication Verification
         Criteria, Deltagen will pay a fixed fee per Probe Array of the greater
         of: *** of Affymetrix' then-current regional (relative to where the
         Probe Arrays are to be used by Deltagen) list price for that Probe
         Array, as published in Affymetrix' catalog; or, ***. After the
         Beginning Period and during the remainder of the Term (and any Extended
         Term), for each expression Probe Array (excluding those Probe Arrays
         for use in internal use or Services) delivered to Deltagen or its
         Affiliates that meet the Fabrication Verification Criteria, Deltagen
         will pay a fixed fee per Probe Array of the greater of: *** of
         Affymetrix' then-current regional (relative to where the Probe Arrays
         are to be used by Deltagen) list price for that Probe Array, as
         published in Affymetrix' catalog; or, ***. The foregoing
         notwithstanding, genetic information access fees actually paid by
         Affymetrix to a third party with respect to Proprietary Probe Array(s)
         will not be discounted and will be passed through to Deltagen without
         mark-up as part of the fee payable hereunder with respect to such
         Proprietary Probe Array(s), but only to the extent that the genetic
         information access fees are not reflected in the list price of standard
         equivalently sized Probe Arrays.

5.3      For each Probe Array to be used in Services delivered to Deltagen or
         its Affiliates that meet the Fabrication Verification Criteria,
         Deltagen shall pay *** of Affymetrix' then current local (relative to
         the country in which the Datapoints from such Service is to be used by
         the customer) list as published in its catalog or, if applicable, the
         price for the equivalent probe arrays from Affymetrix then available to
         that particular third party recipient of such Services (if lower). ***
         For each expression Probe Array to be used for Deltagen's internal use
         delivered to Deltagen or its Affiliates during the Term that meet the
         Fabrication Verification Criteria, Deltagen will pay a fixed fee per
         Probe Array of the greater of: *** of Affymetrix' then-current regional
         (relative to where the Probe Arrays are to be used by Deltagen) list
         price for that Probe Array, as published in Affymetrix' catalog; or,
         ***.

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -16-
<PAGE>

5.4      Notwithstanding the foregoing or any provision to the contrary in
         this Agreement, Deltagen will be responsible for any and all
         royalties due to third parties for Probe Arrays supplied to Deltagen
         hereunder and/or with respect to the manufacture, sale,
         reproduction, distribution or use of any Database(s) or
         Datapoint(s). If Deltagen arranges with such a third party to pay
         such a royalty directly to such party, Deltagen shall at Affymetrix'
         request provide reasonably sufficient documentation to evidence such
         direct royalty payments to such third party, provided that Deltagen
         shall not be required to breach any confidentiality obligations owed
         to such third party. In the event Deltagen is sued by a third party
         based on a claim that Deltagen's use of the Probe Arrays, System(s)
         or Software provided hereunder infringes such third party's
         intellectual property rights, Deltagen may terminate this Agreement
         on fifteen (15) days prior written notice provided that if Deltagen
         so terminates, Affymetrix' indemnity obligations, if any, arising
         from such suit pursuant to Section 10.1 shall be limited to
         Deltagen's liability arising out of events occurring before the date
         of such termination; continued use of Probe Arrays after such
         termination shall be at its own risk.

5.5      At the time and in the manner hereinafter provided, Deltagen shall pay
         to Affymetrix a royalty at the applicable rate according to the table
         below times the Net Sales recognized by Deltagen in accordance with
         GAAP during the applicable royalty reporting period.

<TABLE>
<CAPTION>
        --------------------------------------------------------- ----- ---------------------------------------------
                              TIME PERIOD                                               ROYALTY RATE
        --------------------------------------------------------- ----- ---------------------------------------------
        <S>                                                             <C>
                        During Beginning Period                                             ***
        --------------------------------------------------------- ----- ---------------------------------------------
                         During first year ***                                              ***
        --------------------------------------------------------- ----- ---------------------------------------------
                            Second year ***                                                 ***
        --------------------------------------------------------- ----- ---------------------------------------------
              Third and each subsequent year ***                                            ***
        --------------------------------------------------------- ----- ---------------------------------------------
           After termination of this Agreement (until last to                               ***
        expire Affymetrix patent rights that would otherwise be
                      infringed by such Database)
        --------------------------------------------------------- ----- ---------------------------------------------
</TABLE>

         During the *** of the Beginning Period, and during the period beginning
         on termination of the Agreement and ***, the one-time minimum royalty
         payable by Deltagen per customer/licensee per Database shall be
         calculated according to the following schedule:

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -17-
<PAGE>

<TABLE>
<CAPTION>
         ------------------------------------------------------------------------
                              For Databases Comprised of *
         --------------------------------- ------- ------------------------------ ----------------------------------
         More Than                          But    No More Than                        Minimum Annual Royalty
         --------------------------------- ------- ------------------------------ ----------------------------------
         <S>                               <C>     <C>                            <C>
         *** Datapoints                            The then  applicable  maximum                                ***
                                                   number  of  Datapoints  for a
                                                   Demonstration Database
         --------------------------------- ------- ------------------------------ ----------------------------------
         The  then   applicable   maximum          *** Datapoints                                               ***
         number  of   Datapoints   for  a
         Demonstration Database
         --------------------------------- ------- ------------------------------ ----------------------------------
         *** Datapoints                            *** Datapoints                                               ***
         --------------------------------- ------- ------------------------------ ----------------------------------
         *** Datapoints                            *** Datapoints                                               ***
         --------------------------------- ------- ------------------------------ ----------------------------------
         *** Datapoints                            *** Datapoints                                               ***
         --------------------------------- ------- ------------------------------ ----------------------------------
         *** Datapoints                            *** Datapoints                                               ***
         --------------------------------- ------- ------------------------------ ----------------------------------
         *** Datapoints                            *** Datapoints                                               ***
         --------------------------------- ------- ------------------------------ ----------------------------------
         ***                                                                      Datapoints For Databases comprised
                                                                                  of more than *** Datapoints, the
                                                                                  Parties shall negotiate in good
                                                                                  faith a minimum annual royalty.
         --------------------------------- ------- ------------------------------ ----------------------------------
</TABLE>

         *For purposes of calculating the minimum annual royalty, the size of
         the Database will be measured by the number of Datapoints contractually
         accessible to a customer by way of a contract at inception of the
         applicable contract. It is understood that such licenses are not
         intended to allow license of multiple Demonstration Databases to a
         single customer of the same species that can be combined into a larger
         Database.

         Royalties will be reported and paid quarterly as specified in Section
         5.7. The amount payable per quarter will be calculated according to the
         following formula:

         ***

         Notwithstanding the foregoing, Net Sales otherwise subject to royalties
         accruing pursuant to this Section 5.5 shall be subject to a ***, which
         shall apply to the first *** in Net Sales recognized by Deltagen in
         accordance with GAAP during the term of this Agreement so that,
         notwithstanding the foregoing provisions, ***

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -18-
<PAGE>

         such time as the aggregate ***. However, if this Agreement is
         terminated during the period beginning on the Effective Date and ending
         *** after the Effective Date such *** shall not apply to any Net Sales
         accruing after such termination of the Agreement (even if aggregate Net
         Sales have not exceeded *** as of such termination date).

5.6      Except as to royalty payments, all amounts referred to in this Section
         5 will be invoiced by Affymetrix when due (Affymetrix will invoice for
         Systems and Probe Arrays upon shipment in accordance with Section 3.5).
         Royalty payments will be due as specified in Section 5.7. All payments
         will be made to Affymetrix thirty (30) days from the date of invoicing
         by Affymetrix. Late payments shall bear interest at the rate of ***
         per month. All payments in this Agreement will be made in the form of a
         check or wire transfer to Affymetrix in U. S. Dollars.

5.7      Deltagen shall deliver to Affymetrix, within sixty (60) days after the
         end of each calendar quarter, a written report showing its computation
         of royalty payments due under Section 5.5 of this Agreement, including
         any Net Sales of licenses of Databases by Deltagen or its Affiliates
         during such calendar quarter. All Net Sales shall be segmented in each
         such on a country by country basis, including the rates of exchange
         used to convert such royalties to U. S. Dollars from the currency in
         which the licenses were made. For the purposes of this Agreement, the
         methods and rates of exchange to be used for converting Net Sales in
         foreign currencies into U. S. Dollars for royalty payment purposes
         shall be the same as those used by Deltagen for its financial reporting
         in accordance with GAAP. Simultaneously with the delivery of each such
         report, Deltagen shall tender payment in U. S. Dollars of all royalties
         shown to be due therein. Where royalties are due for licenses of
         Databases in a country where, by reason of currency regulations or
         other legal constraints it is impossible or illegal for Deltagen or its
         Affiliates to transfer royalty payments to Affymetrix, such royalties
         shall be deposited in whatever currency is allowable in a bank in that
         country that is reasonably acceptable to Affymetrix. Any and all income
         or similar taxes imposed or levied on account of the receipt of
         royalties payable under this Agreement which are required to be
         withheld by Deltagen shall be paid or remitted by Deltagen on behalf of
         Affymetrix to the proper taxing authority. Proof of payment or
         remittance shall be secured and sent to Affymetrix as evidence of such
         payment or remittance in such form as required by the tax authorities
         having jurisdiction over Deltagen or its Affiliates. Such withholding
         taxes shall be deducted from the royalty that would otherwise be paid
         by Deltagen or its Affiliates to Affymetrix hereunder.

5.8      Except as provided in Section 5.9, hardware, custom designs, and other
         software, if any, may be acquired/ licensed by Deltagen and its
         Affiliates at Affymetrix'

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -19-
<PAGE>

         regional list prices with discounts and terms no less favorable when
         taken as a whole than granted to other similarly situated un-Affiliated
         licensees or customers of Affymetrix under similar terms and conditions
         (taking into consideration applicable subscription, design and other
         fees payable to Affymetrix by such third parties).

5.9      During the Beginning Period, Deltagen shall purchase the Systems and
         the Software specified on Exhibit B, and may purchase Affymetrix'
         Laboratory Information Management System ("LIMS") and Expression Data
         Management Tool ("EDMT") software at a discount rate of *** from
         Affymetrix' then current regional list prices as published in its
         catalog. After the Beginning Period and during the remainder of the
         Term (and any Extended Term), Deltagen may purchase LIMS and EDMT at a
         discount rate of *** from Affymetrix' then current regional list prices
         as published in its catalog. ***.

5.10     After the Beginning Period, Affymetrix will provide early access to new
         product releases to Deltagen in a manner consistent with its ***
         customers.

5.11     Following Deltagen's request, Affymetrix agrees to consider reasonable
         proposals made by Deltagen in good faith under financial terms
         acceptable to Affymetrix for supply to Deltagen during the Term of
         custom Probe Arrays to be used by Deltagen in generating Databases;
         provided that Affymetrix shall have no obligation hereunder with
         respect to any such proposal and Affymetrix shall be free to reject any
         such proposal for any reason or no reason in Affymetrix' sole absolute
         discretion.

5.12     The parties shall mutually agree upon provisions to be added by written
         amendment to this Agreement concerning Custom Probe Arrays.

6        INTELLECTUAL PROPERTY

6.1      Any invention made during the course of and as part of this Agreement
         shall be owned according to inventorship of the relevant applications.
         Deltagen shall be the owner of all Datapoints and Databases. However,
         Deltagen (and its Affiliates) agree to assign to Affymetrix at
         Affymetrix' cost all Chip Improvement Inventions. Deltagen agrees to
         communicate periodically all technology improvements and developments
         that Deltagen reasonably believes are Chip Improvement Inventions to
         the Committee.

6.2      All Chip Improvement Inventions made available to Affymetrix hereunder
         shall be on an as-is basis. DELTAGEN DISCLAIMS ALL OTHER
         REPRESENTATIONS AND WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, BUT NOT
         LIMITED TO, THE IMPLIED WARRANTIES RELATING TO INTELLECTUAL PROPERTY,
         MERCHANTABILITY, AND

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -20-
<PAGE>

         FITNESS FOR A PARTICULAR PURPOSE. Deltagen makes no warranty that it
         will ever develop any Chip Improvement Invention. Deltagen shall have
         no liability under any theory of strict liability, negligence, whether
         active or passive, or products liability on account of the manufacture,
         use, license, or sale of Chip Improvement Inventions or products or
         Probe Arrays that contain or make use of any Chip Improvement
         Invention.

6.3      Subject to any prior rights of and Deltagen's contractual obligations
         and commitments to third parties (including prior rights and
         contractual obligations and commitments that arise after the Effective
         Date), in the event Deltagen or its Affiliate intends to exclusively
         license a invention to an un-Affiliated third party that is directed to
         a particular *** or its use that was primarily discovered through use
         of Probe Array(s) delivered hereunder, Affymetrix shall have the right
         of first refusal to negotiate with Deltagen or its Affiliate and
         execute an exclusive license to the applicable claims of such invention
         (if any) under mutually agreeable terms and conditions solely in the
         field of manufacture and use of probe arrays and systems (fluidics
         station(s), work station(s), probe array reader(s), hybridization ovens
         and any other systems or equipment) for use therewith manufactured by
         or for Affymetrix or its Affiliate(s). In the event Affymetrix and
         Deltagen are unable to reach agreement with regard to such exclusive
         license within 120 days of Affymetrix receiving notice from Deltagen or
         its Affiliate of such invention claims, Deltagen may then offer such
         license to other un-Affiliated third parties on an exclusive or
         non-exclusive basis provided that Deltagen shall not offer such
         exclusive license to any other un-Affiliated third party on terms and
         conditions more favorable, taken as a whole, to such party than those
         last offered by Affymetrix, taken as a whole, without first offering
         Affymetrix such more favorable terms and a reasonable time period (not
         to exceed 5 business days) for Affymetrix and Deltagen to negotiate
         such license. If Deltagen determines to offer such invention claims for
         license on a non-exclusive basis, Deltagen agrees to negotiate in good
         faith for at least non-exclusive access to Affymetrix under mutually
         agreeable terms and conditions to all Deltagen (and its Affiliates)
         owned inventions that are directed to particular *** or their uses
         that were primarily discovered through use of the Probe Arrays
         delivered hereunder, and such access will only be granted in the field
         of manufacture and use of probe arrays and systems (fluidics
         station(s), work station(s), probe array reader(s), hybridization ovens
         and any other systems or equipment) for use therewith made by or for
         Affymetrix or its Affiliate(s). Such non-exclusive access will be
         negotiated to include royalty and other payments no less favorable,
         taken as a whole, than granted to other similarly situated
         un-Affiliated third party licensees, and need only be provided if
         legally licensable at the time the invention is made. Deltagen

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -21-
<PAGE>

         need not report such inventions until after publication in, for
         example, an issued patent or a patent application (depending on the
         jurisdiction).

6.4      In the event Deltagen or its Affiliate intends to exclusively
         license a invention to an un-Affiliated third party that is directed
         to (a) *** techniques (but only insofar as such *** techniques
         relate to *** or (b) software, techniques or methods for ***,
         Affymetrix shall have the right of first refusal to negotiate with
         Deltagen or its Affiliate and execute an exclusive license to the
         applicable claims of such invention (if any) under mutually
         agreeable terms and conditions solely in the field of manufacture
         and use of probe arrays and systems (fluidics station(s), work
         station(s), probe array reader(s), hybridization ovens and any other
         systems or equipment) for use therewith manufactured by or for
         Affymetrix or its Affiliate(s). In the event Affymetrix and Deltagen
         are unable to reach agreement with regard to such exclusive license
         within 120 days of Affymetrix receiving notice from Deltagen or its
         Affiliate of such invention claims, Deltagen may then offer such
         license to other un-Affiliated third parties on an exclusive or
         non-exclusive basis provided that Deltagen shall not offer such
         exclusive license to any other un-Affiliated third party on terms
         and conditions more favorable, taken as a whole, to such party than
         those last offered by Affymetrix, taken as a whole, without first
         offering Affymetrix such more favorable terms and a reasonable time
         period (not to exceed 5 business days) for Affymetrix and Deltagen
         to negotiate such license. If Deltagen determines to offer such
         invention claims for license on a non-exclusive basis, Deltagen
         agrees to negotiate in good faith for at least non-exclusive access
         to Affymetrix under mutually agreeable terms and conditions to all
         Deltagen (and its Affiliates) owned inventions that are directed to
         particular Genes or their uses that were primarily discovered
         through use of the Probe Arrays delivered hereunder, and such access
         will only be granted in the field of manufacture and use of probe
         arrays and systems (fluidics station(s), work station(s), probe
         array reader(s), hybridization ovens and any other systems or
         equipment) for use therewith made by or for Affymetrix or its
         Affiliate(s). Such non-exclusive access will be negotiated to
         include royalty and other payments no less favorable, taken as a
         whole, than granted to other similarly situated un-Affiliated third
         party licensees, and need only be provided if legally licensable at
         the time the invention is made. Deltagen need not report such
         inventions until after publication in, for example, an issued patent
         or a patent application (depending on the jurisdiction).

6.5      Affymetrix and Deltagen will negotiate in good faith for Deltagen to
         act as a nonexclusive agent for license of Affymetrix' LIMS and EDMT
         software for use with Deltagen's database products, PROVIDED THAT
         notwithstanding anything to the contrary in this Agreement, Deltagen,
         its Affiliates, its Research Partners and its

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -22-
<PAGE>

         customers *** Affymetrix-specified *** or *** in connection with use
         of the *** or *** generated therefrom. To the extent Affymetrix
         specifies that certain *** and *** be used with *** and Deltagen
         elects not to follow such specification, then Affymetrix shall have
         no liability under this Agreement for any damage to such *** or the
         System(s), of any failure in the performance thereof that is caused
         by Deltagen's use of such non-specified ***, and Affymetrix'
         indemnity obligations under Section 10.1 shall not apply to any
         third party claim(s) of infringement caused by Deltagen's use of
         such nom-specified *** or *** (which claims of infringement shall be
         deemed "Non-Covered Claims" for purposes of Section 10.1).
         Furthermore, the foregoing statement of no contractual obligation
         shall not be construed to convey or imply any right or license under
         any intellectual property right of Affymetrix or its Affiliates.

6.6      Deltagen understands that no license is conveyed or implied for use of
         the Systems herein for probe arrays other than those manufactured or
         licensed by Affymetrix.

7        PROJECT COORDINATION

7.1      The parties will form the Committee, which shall be composed of such
         representatives of Affymetrix and Deltagen as each shall respectively
         appoint and be reasonably acceptable to the other Party. Each Party by
         its representative( s) shall cast one vote on the Committee. A quorum
         shall consist of at least one Committee representative from each Party.
         The Committee shall act only with the concurring votes of both Parties.
         A Party's representatives shall serve at the discretion of such Party
         and may be substituted for or replaced at any time by such Party. The
         Committee shall meet at least quarterly during the Term, except at such
         times as the Parties mutually believe there are no significant agenda
         items. The site of such meetings shall alternate between the offices of
         Affymetrix and Deltagen, (or any other site mutually agreed upon by the
         Parties) or be arranged by video conference. The proceedings of all
         meetings of the Committee shall be prepared alternately by the Parties,
         unless otherwise agreed, and sent to both Parties. In the event that
         the Committee is unable to reach a decision by unanimous action with
         respect to any matter and such inability continues for a period of
         forty- five (45) days after the date on which the matter is first
         submitted to the Committee, each Party shall refer the matter to the
         Chief Executive Officers of Affymetrix and Deltagen for resolution.
         Each Party shall set forth in writing a proposed solution to the
         impasse. If an acceptable resolution is not achieved, either party may
         choose to arbitrate the issue( s) in accordance with Section 12.7.

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -23-
<PAGE>

         The Parties shall use reasonable efforts to continue performance of
         this Agreement during any such dispute.

7.2      The basic purpose of the Committee shall be to aid in coordinating the
         performance of this Agreement, although each Party shall remain
         responsible for the day to day performance of its respective duties and
         obligations under and pursuant to the terms of this Agreement. The
         charter and authority of the Committee shall be mutually agreed upon by
         the Parties. In no event, however, shall the Committee have the
         authority to amend this Agreement or to waive, or waive the performance
         of, any provision hereof.

8        CONFIDENTIALITY

8.1      For a period of 5 years from disclosure to the other Party, each Party
         shall maintain the Confidential Information of the other Party in
         confidence (including the terms of this Agreement), and shall not
         knowingly disclose, divulge, or otherwise communicate such Confidential
         Information of the other, or use it for any purpose, except as
         permitted or contemplated by this Agreement, and in order to carry out
         the terms and objectives of this Agreement. The Parties will use
         reasonable precautions to prevent and restrain the unauthorized
         disclosure of such Confidential Information of the other Party. The
         provisions of this paragraph and Section 8.2 shall not apply to
         Confidential Information which:

8.1.1    was known or used by the receiving Party or its Affiliates without any
         restriction on disclosure, prior to its date of disclosure to the
         receiving Party, as evidenced by the prior written records of the
         receiving Party or its Affiliates; or

8.1.2    either before or after the date of the disclosure to the receiving
         Party is lawfully disclosed without restriction on disclosure to the
         receiving Party or its Affiliates by an independent, unaffiliated third
         party rightfully in possession of the Confidential Information,
         provided that if such Confidential Information is provided to the
         receiving Party by a third party rightfully in possession of the
         Confidential Information, but with restrictions on disclosure, the
         receiving Party may use such Confidential Information in accordance
         with such restrictions of the third party;

8.1.3    either before or after the date of the disclosure to the receiving
         Party becomes published or generally known to the public through no
         fault or omission of the receiving Party or its Affiliates;

8.1.4    is required to be disclosed by the receiving Party or its Affiliates to
         comply with applicable laws, to comply with a court order, or to comply
         with governmental regulations, provided that the receiving Party
         provides reasonable (prior, if feasible) written notice of such
         disclosure to the other Party and the receiving

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -24-
<PAGE>

         Party cooperates with the other Party, at the other Party's expense and
         upon the other Party's reasonable written request, in taking reasonable
         and lawful actions to avoid and/or minimize the degree of such
         disclosure;

8.1.5    is independently developed by the receiving Party or its Affiliates
         without reference to the Confidential Information.

8.2      Deltagen may not publish in a journal article or other publication any
         benchmark results comparing the use of the Probe Arrays with other
         competitive technologies without the prior written approval of
         Affymetrix. Affymetrix may not publish results of the use of the Probe
         Arrays that include any results derived by Deltagen without the prior
         written approval of Deltagen. Subject to the limitations of the
         foregoing and Section 3 above, Deltagen may publish the results of its
         research and/or use of the Probe Arrays at its sole discretion,
         provided that in no event shall Deltagen publish Affymetrix'
         Confidential Information or Chip Improvement Inventions without
         Affymetrix' consent. In the event that Deltagen chooses to publish such
         results, if Affymetrix scientists have contributed to such work, then
         authorship will be according to scientific input in accordance with
         applicable industry standards for such matters and Affymetrix will
         cooperate in such publications. If a Party decides to make a
         publication that requires the prior approval of the other Party
         pursuant to this Section, then the publishing Party will provide the
         other Party with draft versions of all such publications at least 60
         days prior to submission, for the other Party's approval (and, if
         approval is given, technical review), and will allow for removal of the
         other Party's Confidential Information. For purposes of this Section
         "publication" shall not mean the license of Databases or the provision
         of Services hereunder.

9        WARRANTY

9.1      Both Parties to this Agreement represent and warrant that they have the
         full right and authority to enter into and perform this Agreement.

9.2      Affymetrix warrants that the Probe Arrays delivered hereunder do not
         incorporate the *** of a third party anywhere in the world or, to
         its *** (provided that such obligation to perform *** shall be fully
         satisfied by ***, for purposes of disclosure to the relevant ***
         during ***), *** of a third party in the ***. EXCEPT AS OTHERWISE
         PROVIDED HEREIN, AFFYMETRIX DISCLAIMS ALL OTHER REPRESENTATIONS AND
         WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE
         IMPLIED WARRANTIES RELATING TO MERCHANTABILITY, AND FITNESS FOR A
         PARTICULAR PURPOSE. Affymetrix shall have no liability under any
         theory of strict liability, negligence,

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -25-
<PAGE>

         whether active or passive, or products liability. Affymetrix' entire
         liability shall in no event exceed the compensation hereunder.
         Affymetrix shall have no liability under this Section for any indirect,
         consequential, incidental, or special damages. Deltagen understands
         that the risks of loss herein are reflected in the price of the Probe
         Arrays and access fees and that the terms would have been different if
         there had been a different allocation of risk.

9.3      AFFYMETRIX warrants that (i) all *** provided hereunder shall meet
         the *** and shall be ***, provided that Deltagen's sole and
         exclusive remedy and Affymetrix' sole and exclusive liability for a
         breach of this warranty in this subsection (i) shall be limited to
         those express provisions set forth in Sections 3 and 5 above and
         (ii) for one (1) year from the date of shipping, the System and the
         Software shall be free from defects in design, materials and
         workmanship; shall operate in accordance with Affymetrix' respective
         documentation, manuals and published specifications in all material
         respects; and, in the case of the Software, shall, at the time of
         shipment, constitute the most recent generally available release or
         version thereof. Support services for Software and Systems will be
         provided pursuant to Affymetrix' standard service terms. Affymetrix'
         sole and exclusive liability (and Deltagen's sole and exclusive
         remedy) under the foregoing warranty shall be to repair or replace
         Software and Systems or provide Deltagen a refund, as solely
         determined by Affymetrix. Nonconforming Systems will be serviced at
         Deltagen's facility or, at Affymetrix' option, Affymetrix' facility.
         If service is performed at Affymetrix' facility, Affymetrix will
         bear shipping costs. This warranty does not apply to any defect
         caused by failure to provide a suitable storage, use, or operating
         environment, use of non-recommended reagents, or the use of the
         Probe Arrays, Systems or Software for a purpose or in a manner other
         than that for which they were designed, modifications or repairs
         done by Deltagen, or any other abuse, misuse, or neglect of such
         products. This warranty applies only to Deltagen and its Affiliates,
         and not third parties.

10       INDEMNITY

10.1     Affymetrix will settle or defend any suit or proceeding brought
         against Deltagen and its Affiliates to the extent based on a claim
         that the Probe Arrays, System or Software delivered hereunder or
         their use in accordance with this Agreement and Affymetrix's
         standard documentation (e.g., System manuals) directly infringes an
         issued patent in the United States of America, the EPO or Japan.
         Affymetrix will settle or defend any suit or proceeding brought
         against Deltagen to the extent based on a claim that the
         manufacture, sale or license by Affymetrix or its Affiliates of
         Probe Arrays, System and/or Software delivered hereunder indirectly
         (i. e. through contributory infringement or inducement) infringes a
         patent issued in or by the United States of America, EPO and/or
         Japan. Affymetrix shall have no liability under this paragraph to
         the extent that the

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -26-
<PAGE>

         alleged infringement arises out of any addition or modification to
         the Probe Arrays or their use by Deltagen not specified by
         Affymetrix in, or not contemplated by, this Agreement or any such
         standard documentation, or Deltagen's combination of the Probe
         Arrays with other devices not specified or provided by Affymetrix.
         Patent claims that meet all of the following three criteria are
         referred to herein as "Non-Covered Claims:" (i) the claim arises
         solely out of Deltagen's use of the Probe Arrays, System or
         Software; (ii) Affymetrix does not indemnify Deltagen with respect
         to such claim under the first two sentences of this Section 10.1;
         and (iii) the claim is for infringement of a patent issued in or by
         the United States of America, the EPO and/or Japan. Deltagen will
         settle or defend any suit or proceeding arising out of Deltagen's
         specific use of Probe Arrays, which suit or proceeding is based on
         an issued patent the United States of America, the EPO or Japan
         brought against Affymetrix for Non-Covered Claims. The indemnifying
         Party shall pay all damages and costs finally awarded against the
         indemnified Party for such infringement. For this paragraph to apply
         the indemnified Party must inform the indemnifying Party within 14
         days of notice of any claim or suit being made or brought, and give
         the indemnifying Party the full authority, information, and
         assistance necessary to settle or defend such suit or proceeding.
         The indemnifying Party shall not be bound in any manner by any
         settlement made without its prior written consent. Each indemnifying
         Party's liability hereunder (except for costs of defense and with
         respect to claims of willful infringement) shall be limited to an
         amount equal to the total amount paid. In the event that the Probe
         Arrays are held to infringe and their use is enjoined as a result of
         infringement (not limited to those for which it has an obligation to
         indemnify Deltagen), Affymetrix may obtain for Deltagen the right to
         continue using such Probe Arrays, modify them to become
         noninfringing, or grant Deltagen a credit equal to the cost of all
         affected Probe Arrays that are unused, and accept the return of such
         unused Probe Arrays, or, alternatively, a credit equal to the amount
         which Deltagen is legally obliged to pay as a royalty to the third
         party for use of such Probe Arrays. This Section 10.1 states the
         entire liability for infringement of intellectual property rights
         and is in lieu of all other warranties, express or implied except as
         stated in Section 9.

11       TERM AND TERMINATION

11.1     This Agreement shall extend until the end of the Term unless terminated
         earlier by a Party for cause by written notice if the other Party (or
         its Affiliate) materially breaches any material provision of this
         Agreement and fails to substantially cure such breach within 30 days of
         written notice describing the breach and the intent of the notifying
         Party to terminate the Agreement in the event such breach is not

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -27-
<PAGE>

         substantially cured. In addition, in the event Deltagen elects
         option (b) as set forth in Section 5.1, Deltagen may terminate this
         Agreement without cause and without liability to Affymetrix on not
         less than ninety (90) days prior written notice given at any time
         within the period beginning nine (9) months after the end of the
         Beginning Period and ending fifteen (15) months after the end of the
         Beginning Period.

11.2     Upon termination of this Agreement due to expiration of the Term or for
         any reason other than a material, uncured breach by Deltagen of a
         material provision of this Agreement, Deltagen may continue in
         accordance with this Agreement (i) to use the Software, (ii) to use the
         Probe Arrays previously purchased by Deltagen within their specified
         shelf life, all subject to the warranty and return provisions provided
         in this Agreement, and (iii) to use and sublicense the Datapoints and
         Databases.

11.3     Upon termination of this Agreement, the following provisions will
         survive: 2, 3.5, 3.6, 3.8, 3.9, 3.10, 4.2*, 5.2**, 5.3**, 5.4, 5.5***,
         5.6, 5.7, 6, 8, 9, 10, 11.2, 11.3, and 12. (* Except in the case where
         this Agreement is terminated due to a material, uncured breach by
         Deltagen of a material provision of this Agreement.) (** To the extent
         obligations are accrued prior to the termination date.) (*** For the
         avoidance of doubt, Deltagen's obligation to pay royalties for a
         Database shall survive termination of this Agreement and persist until
         the expiration of the last to expire Affymetrix patent rights that
         would otherwise be infringed by such Database.)

12       MISCELLANEOUS

12.1     Deltagen shall keep, and shall cause its Affiliates to keep, for a
         period of at least two (2) years full, accurate, and true books of
         accounts and other records containing all information and data which
         may be necessary to ascertain and verify the fees and royalties payable
         hereunder. During the Term of this Agreement and for a period of two
         (2) years following the time at which the relevant fee or payment is
         due, Affymetrix shall have the right from time to time (not to exceed
         once during a calendar year or once with respect to any given period)
         to have an independent certified public accountant reasonably
         acceptable to Deltagen audit in confidence such books, records, and
         supporting data on reasonable advance written notice and at their
         normal location. Any such audit shall be conducted so as to have the
         minimum impact on the normal conduct of Deltagen's business and
         operations and such auditor shall only disclose to Affymetrix his
         conclusion and summary information showing whether or not Deltagen has
         made correct payment of the fees and royalties payable hereunder, or,
         if not, the extent and nature of any discrepancy. In the event it is
         finally

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -28-
<PAGE>

         determined that there is a discrepancy initially revealed by an audit
         reveals greater than 5% in the relevant period, Deltagen will pay any
         reasonable audit fees.

12.2     DELTAGEN UNDERSTANDS THAT THE PROBE ARRAYS DELIVERED HEREUNDER ARE NOT
         FDA APPROVED. DELTAGEN AGREES NOT TO USE THE PROBE ARRAYS DELIVERED
         HEREUNDER IN ANY CLINICAL OR OTHER SETTING REQUIRING FDA REVIEW OR
         APPROVAL EXCEPT THAT DELTAGEN MAY USE THE PROBE ARRAYS IN CLINICAL
         TRIALS WHEN IT OBTAINS ALL REQUIRED FDA OR OTHER REGULATORY APPROVALS
         REQUIRED FOR USE IN SUCH TRIALS. DELTAGEN WILL INDEMNIFY AFFYMETRIX FOR
         ANY CLAIMS MADE BY A PATIENT ARISING FROM THE USE OF THE PROBE ARRAYS.
         THE PROBE ARRAYS AND SYSTEMS ARE NOT LICENSED EXCEPT AS SPECIFICALLY
         RECITED HEREIN UNDER ANY INTELLECTUAL PROPERTY RIGHTS OF AFFYMETRIX.

12.3     SUBJECT TO SECTION 9 AND 10, NEITHER PARTY SHALL ANY LIABILITY FOR
         PUNITIVE, EXEMPLARY, CONSEQUENTIAL, INCIDENTAL, OR SPECIAL DAMAGES.

12.4     Neither Party nor any of its Affiliates shall originate any news
         relating to this Agreement without the prior written approval of the
         other Party, which approval shall not be unreasonably withheld, or
         except as otherwise required by law.

12.5     Either Party may assign any rights or obligations of this Agreement
         to (i) an Affiliate, (ii) any third party who acquires all or
         substantially all of the relevant assets of the assigning Party by
         merger or sale of assets or otherwise or (iii) with the written
         consent of the other Party (not to be unreasonably withheld), any
         other third party. Notwithstanding the foregoing and only at
         Affymetrix' option, to be exercised by providing notice in writing
         to Deltagen within ten (10) business days of having received written
         notice of the pendency of such transaction, if Deltagen is acquired
         by or otherwise makes an assignment hereof to a company or an
         Affiliate of a company that, at the time of assignment, either (i)
         has a significant business (defined as a business whose primary
         source of gross revenue is derived from sale of nucleic acid arrays
         and such gross revenue is not less than $50,000,000 per year) in
         nucleic acid arrays (including, without limitation, if this
         provision were applicable as of the date of this Agreement, Agilent,
         Amersham Pharmacia Biotech, Bickman Coulter, Celera, Corning,
         Hitachi, Hyseq, Incyte, Motorola, Oxford Gene Technologies, PE
         Biosystems, Rosetta Impharmatics) or (ii) is a party or an Affiliate
         of a party to material litigation with Affymetrix or its Affiliate
         with respect to allegation(s) of patent infringement, then, provided
         that Affymetrix (A) refunds to the assignee or Deltagen (as Deltagen
         elects) the pro-rated portion of the payment under Section 5.1 for
         the remainder of the year in which the assignment occurs; (B) agrees
         in writing that the assignee is not obligated to make payment under
         this Agreement other than unpaid amounts (if any) due with respect
         to period(s) ending on or before the date of assignment and, subject
         to the *** set forth in Section 5.5, royalties

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -29-
<PAGE>

         accruing on Net Sales of the assignee thereafter; and (C)
         repurchases, at Deltagen's fully-loaded cost (including cost of
         capital), all of Deltagen's inventory of unused Probe Arrays on hand
         as of the date of assignment (if Deltagen so elects), then such
         assignee's rights hereunder shall be limited to commercializing
         Database(s) that make use of or include Datapoints that either
         existed prior to such assignment by Deltagen or, if Deltagen elects
         not to have Affymetrix repurchase all unused Probe Arrays pursuant
         to clause (C) preceding, are generated after such assignment from
         use of Probe Arrays in Deltagen's inventory as of the date of
         assignment, and such assignee shall not, without Affymetrix prior
         written consent which Affymetrix may withhold for any reason or no
         reason in Affymetrix' absolute sole discretion, be entitled
         hereunder to purchase additional Affymetrix products nor otherwise
         create new Datapoints.

12.6     This Agreement shall be construed according to the laws of California
         without regard to conflict of law provisions.

12.7     In the event of any controversy or claim relating to, arising out of or
         in any way connected to any provision of this Agreement ("Dispute"),
         the Parties shall seek to settle their differences amicably between
         themselves. Any unresolved Dispute shall be finally resolved by final
         and binding arbitration. Whenever a Party shall decide to institute
         arbitration proceedings, it shall give written notice to that effect to
         the other Party. The Party giving such notice shall refrain from
         instituting the arbitration proceedings for a period of ten (10) days
         following such notice to allow the Parties to attempt to resolve the
         Dispute between themselves. If the Parties are still unable to resolve
         the dispute, the Party giving notice may institute the arbitration
         proceeding under the rules of the American Arbitration Association
         ("AAA Rules"). Arbitration shall be held in Palo Alto, California. The
         arbitration shall be conducted before a single arbitrator mutually
         chosen by the Parties, but if the parties have not agreed upon a single
         arbitrator within fifteen (15) days after notice of the institution of
         the arbitration proceeding, then the arbitration will be conducted by a
         panel of three arbitrators. In such case, each Party shall within
         thirty (30) days after notice of the institution of the arbitration
         proceedings appoint one arbitrator. The third and presiding arbitrator
         shall then be appointed by the AAA in accordance with AAA Rules. All
         arbitrator(s) eligible to conduct the arbitration must undertake in
         writing as a condition of service to render their opinion( s) promptly
         after the final arbitration hearing. No arbitrator (nor the panel of
         arbitrators) shall have the power to award punitive damages or any
         award of multiple damages under this Agreement and such awards are
         expressly prohibited. Decisions of the arbitrator(s) shall be final and
         binding on the Parties. Judgment on the award of the arbitrator(s) may
         be entered in any court having jurisdiction thereof. Except to the
         extent entry of judgment and any subsequent enforcement may require
         disclosure, all matters relating to the arbitration, including the
         award, shall be held in confidence by the Parties.

12.8     The waiver by either Party of a breach or a default of any provision of
         this

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -30-
<PAGE>

         Agreement by the other Party shall not be construed as a waiver of any
         succeeding breach of the same or any other provision, nor shall any
         delay or omission on the part of either Party to exercise or avail
         itself of any right power or privilege that it has or may have
         hereunder operate as a waiver of any right, power or privilege by such
         Party.

12.9     This Agreement and the documents referred to herein are the full
         understanding of the Parties with respect to the subject matter hereof
         and supersede all prior understandings and writings relating to the
         subject matter herein. No waiver alteration or modification of any of
         the provisions herein shall be binding unless in writing and signed by
         the Parties by their respective authorized representatives. In the
         event of a conflict or inconsistency between the provisions of this
         Agreement and the provisions of any license or other documentation
         provided by Affymetrix with the Systems, Software, Probe Arrays,
         reagents or any other Affymetrix product, then the provisions of this
         Agreement shall govern.

12.10    The headings in this Agreement are for convenience only and shall not
         be considered in construing this Agreement.

12.11    In the event that any provision of this Agreement is held by a court of
         competent jurisdiction to be unenforceable because it is invalid or in
         conflict with any law of any relevant jurisdiction, the validity of the
         remaining provisions shall not be affected, and the rights and
         obligations of the Parties shall be construed and enforced as if the
         Agreement did not contain the particular provision(s) held to be
         unenforceable.

12.12    This Agreement shall be binding on and inure to the benefit of the
         Parties and their successors and permitted assigns.

12.13    None of the provisions of this Agreement shall be for the benefit of or
         enforceable by any third party.

12.14    Any notice required under this Agreement shall be made by overnight
         mail or courier to the addresses below.

         If to Deltagen:

                  Deltagen, Inc.
                  1003 Hamilton Avenue
                  Menlo Park, CA 94025
                  Attn: President (with a copy to General Counsel)
                  Facsimile Number: (650) 752-0202

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -31-
<PAGE>

         If to Affymetrix:
                  Affymetrix, Inc.
                  3380 Central Expressway
                  Santa Clara, California 95051
                  Attn: General Counsel
                  Facsimile Number: (408) 481- 4709

12.15    "Force Majeure" shall mean an Act of God, flood, fire, explosion,
         earthquake, strike, lockout, casualty or accident, war, civil
         commotion, act of public enemies, blockage or embargo, or any
         injunction, law, order proclamation, regulation, ordinance, demand or
         requirement of any government or any subdivision, authority
         representative thereof, or the inability to procure or use materials,
         labor, equipment, transportation or energy sufficient to meet
         manufacturing needs without the necessity of allocation, or any other
         cause whatsoever, whether similar or dissimilar to those enumerated
         above, which are beyond the reasonable control of such Party, which the
         party affected has used its reasonable best efforts to avoid, and which
         prevent, restrict or interfere with the performance by a Party of its
         obligations hereunder. The Party affected by Force Majeure shall give
         notice to the other Party promptly in writing and whereupon shall be
         excused from those obligations hereunder, to the extent of such
         prevention, restriction or interference, provided that the affected
         Party shall use its commercially reasonable efforts to overcome, avoid
         or remove such cause(s) of non-performance and shall continue
         performance whenever such cause(s) is removed with all possible speed.
         Nothing herein shall be deemed to require any Party to settle on terms
         unsatisfactory to such Party with regard to any strike, lockout or
         other labor difficulty, any investigation or proceeding by any public
         authority or any litigation by any third party.

12.16    This Agreement may be executed in any number of counterparts, each of
         which shall be deemed an original but all of which together shall
         constitute one and the same instrument.

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -32-
<PAGE>

IN WITNESS WHEREOF, the Parties hereto have caused this Agreement to be executed
by their properly and duly authorized officers or representatives as set forth
below.

Affymetrix, Inc.

By:  /s/ Susan E. Siegel
   ---------------------------------

Name: Susan E. Siegel
     -------------------------------

Title: President
      ------------------------------

Date: 7/12/00
     -------------------------------

Deltagen, Inc.

By: /s/ William Matthews
   ---------------------------------

Name: William Matthews
     -------------------------------

Title: Chief Executive Officer
      ------------------------------

Date: July 12, 2000
     -------------------------------

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -33-
<PAGE>

                                    EXHIBIT A

                          INITIAL PROBE ARRAY FORECAST

TBD

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -34-
<PAGE>

                                    EXHIBIT B

                          SOFTWARE AND HARDWARE ORDERS

<TABLE>
<CAPTION>
ITEM NUMBER                DESCRIPTION                                 QUANTITY
--------------------------------------------------------------------------------
<S>                        <C>
                                       ***
</TABLE>

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -35-
<PAGE>

                                    EXHIBIT C

                        FABRICATION VERIFICATION CRITERIA

I.       GENE EXPRESSION ARRAY FABRICATION VERIFICATION

         -  ***

              -  ***

              -  ***

         -  ***

              -  ***

              -  ***

II.      CHIP DESIGN QUALITY CHECK

         -  ***

              -  ***

              -  ***

              -  ***

III.     QC TESTING PROCEDURE

         -  ***

              -  ***

              -  ***

         -  ***

              -  ***

              -  ***

IV.      GE ARRAY QC TESTING PROCEDURE

         -  ***

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -36-
<PAGE>



              -  ***

              -  ***

              -  ***

         -  DOP AD027

              -  Assay

                   -  ***

                   -  ***

              -  Analysis

                   -  ***

                   -  ***


V.       GE ARRAY QC TESTING CRITERIA

         1. ***

              -  ***

         2. ***

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -37-
<PAGE>

                                    EXHIBIT D

                                       RMA

[***] Confidential Treatment Requested. The confidential portions have been
filed separately with the Securities & Exchange Commission.


                                      -38-