Document:

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                                                                   EXHIBIT 10.18

    [CONFIDENTIAL TREATMENT REQUESTED. CONFIDENTIAL PORTIONS OF THIS AGREEMENT
    HAVE BEEN REDACTED AND HAVE BEEN SEPARATELY FILED WITH THE COMMISSION.]

                              TECHNOLOGY AGREEMENT

                      GENERATION OF KNOCKOUT MOUSE STRAINS

                                     BETWEEN

                                 DELTAGEN, INC.
                                1031 Bing Street
                              San Carlos, CA 94070

                                       and

                                   PFIZER INC.
                                235 East 42nd St.
                            New York, New York 10017

WHEREAS, Deltagen, Inc. ("Deltagen") and Pfizer Inc. ("Pfizer"), (collectively,
"Parties") seek to collaborate in scientific research related to generation of
Knockout mouse strains;

WHEREAS, Deltagen has knowledge and experience in research and generation of
Knockout mice; and

WHEREAS, Pfizer wishes to obtain Knockout mice generated by Deltagen according
to specifications agreed by the Parties.

1.       DEFINITIONS

As used in this Agreement the following terms shall have the meanings as
specified:

         1.1      "Pfizer Affiliate" shall mean (i) any corporation or business
entity of which fifty percent (50%) or more of the securities or other ownership
interest representing the equity, the voting stock or general partnership
interest are owned, controlled or held, directly or indirectly, by Pfizer; or
(ii) any corporation or business entity which, directly or indirectly, owns,
controls, or holds 50 percent (50%) (or the maximum ownership permitted by law)
or more of the securities or other ownership interest representing the equity,
the voting stock or, if applicable, the general partnership interest, of Pfizer.

         1.2      "Effective Date" shall mean the date of the signature of the
representative of the last of the Parties to execute this Agreement.

         1.3      * * *.

         1.4      * * *.

         1.5      * * *.

* * *  Confidential material redacted and separately filed with the Commission.

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         1.6      "Knockout Mouse Project" shall mean the creation, testing and
generation, by Deltagen, of Knockout mice.

         1.7      * * *.

         1.8      * * *.

         1.9      * * *.

         1.10     * * *.

         1.11     "Milestone Payments" shall mean those payments set forth at
Appendix A attached hereto.

         1.12     * * *.

         1.13     * * *.

         1.14     "Standard Procedure" shall mean the set of procedures
described in Appendix A, with respect to "Milestone 1" through "Milestone 5 ."

2.       RESEARCH AND WORK TO BE CONDUCTED

         2.1      Deltagen shall conduct one or more Knockout Mouse Projects at
the request of Pfizer on the terms and conditions of this Agreement. Pfizer will
request Deltagen in writing to begin work on each Knockout mouse project to be
conducted under this Agreement, such written notice to be provided to Deltagen
by an authorized representative of Pfizer in the form set forth in Appendix B.
Deltagen shall have the right to evaluate such request and the information
provided to Deltagen by Pfizer under Section 2.3 below, to determine whether
such requested Knockout mouse project is feasible. If, after good faith
discussion with Pfizer, Deltagen reasonably determines that such project is not
technically feasible, within the parameters of Appendix A, Deltagen shall so
advise Pfizer in writing and shall not be required to undertake such project.

* * *  Confidential material redacted and separately filed with the Commission.

                                       2
<PAGE>

         2.2      For each Knockout Mouse Project, Deltagen will use reasonable
efforts to complete each Milestone in a timely fashion, as defined in Appendix
A.

         2.3      Deltagen shall undertake up to * * * Knockout Mice Projects
according to the terms and conditions set forth in this Agreement. To initiate
each Knockout mouse project the parties agree to undertake, Deltagen and Pfizer
will establish a timetable for each project Milestone, and Pfizer shall:

                  2.3.1    Identify to Deltagen in writing each Knockout Mouse
Project to be initiated;

                  2.3.2    Disclose in writing to Deltagen any * * * necessary
for Deltagen * * * useful in completing Milestone 1 with respect to each
Knockout Mouse Project, as defined at Appendix A;

                  2.3.3    Consult with Deltagen to * * * for such Knockout
Mouse Project;

                  2.3.4    Transfer to Deltagen any * * * Pfizer deems
appropriate to transfer and which may be suitable for * * *; and

                  2.3.5    Identify and notify Deltagen in writing of the * * *
for each Knockout Mouse Project for which Deltagen is requested by Pfizer to
produce a Knockout Mouse. * * *.

         2.4      For purposes of the schedule set forth in Appendix A, each
Knockout Mouse Project conducted hereunder shall commence fifteen (15) days
after Deltagen's receipt from Pfizer of all information and materials set forth
in Section 2.3 relating to such Knockout Mouse Project.

         2.5      Each Knockout Mouse Project shall be deemed complete upon
Deltagen's completion of Milestone 5 (see Appendix A) and Deltagen's delivery
after the birth of the first generation of Knockout mice of at least * * * and *
* * which are * * *. Deltagen, or a period of six (6) months following the
completion of each Milestone 5 for each Knockout Mouse Project, shall retain a
small backup colony of * * * of Knockout mice * * * from such project consisting
of * * * for each Knockout Mouse Project). With respect to such backup colonies
of Knockout Mice, Pfizer shall for a period not to exceed six (6) months
following completion of Milestone 5 pay to Deltagen * * *. At Pfizer's request,
Deltagen will transfer the mice to Pfizer. All reasonable transportation and
transfer costs shall be paid by Pfizer. If Pfizer does not request transfer
within the six month period, Deltagen, following Deltagen's written notification
to Pfizer, shall dispose of the mice in accordance with all applicable laws and
regulations.

         2.6      Deltagen shall use reasonable efforts to * * * and to generate
Knockout mice under each Knockout mouse project according to the specification
of Pfizer as set forth in Section 2.3 above.

         2.7      Deltagen shall, at all times in its animal care and handling
activities related to this Agreement, comply with all applicable Federal, State
and local laws and

* * *  Confidential material redacted and separately filed with the Commission.

                                       3
<PAGE>

regulations, and assure that Deltagen animal facilities meet or exceed minimum
accreditation standards * * *.

3.       PAYMENTS

         3.1      Within thirty (30) days after the Effective Date and receipt
of invoice, Pfizer shall pay to Deltagen * * * of the total estimated cost for
the * * * Knockout mouse projects * * * as calculated in accordance with
Appendix A. Such payment shall be non-non-readable and shall be credited against
Milestones as set forth in Appendix A. Deltagen will provide invoices to Pfizer
for all payments due under this agreement. Invoices received by Pfizer shall be
paid within thirty (30) days of receipt.

         3.2      Pfizer shall pay to Deltagen for each Milestone completed by
Deltagen:

                  3.2.1    The Milestone Payments set forth in Appendix A are
for all Knockout Mouse Projects wherein a * * * is requested by Pfizer under
Section 2.3 above, so long as the Project is initiated during the term of this
Agreement. The Milestone Payments for all Knockout Mouse Projects wherein * * *
is requested, shall be determined on a case-by-case basis, upon good faith
negotiations between the parties and shall be mutually agreed to in writing by
the parties.

                  3.3      Deltagen shall inform Pfizer, in writing, of its
completion of each Milestone, as defined in Appendix A. In such written notice,
Deltagen shall certify that the Knockout Mice delivered to Pfizer conform to the
Knockout Mice specifications for each Knockout Mouse Project set forth in
Appendix A, and Deltagen shall provide with each delivery of Knockout Mice to
Pfizer all of the information and data described in Appendix A for each Knockout
Mouse Project.

                  3.4      Subject to payment credit as provided in Section 3.1,
Pfizer shall pay all Milestones to Deltagen within thirty (30) days after
Pfizer's receipt of written representation from Deltagen of Deltagen's
completion of Milestones in compliance with the terms of this Agreement.

4.       ON-SITE CONSULTATION

         4.1      Pfizer may reasonably request on-site consultations by
Deltagen personnel relating directly to projects under this Agreement. Pfizer
will reimburse Deltagen for all reasonable and reasonably documented travel
expenses associated with such onsite consultations by Deltagen personnel.

         4.2      Upon reasonable notice to Deltagen and upon reasonable terms
and conditions agreed upon by Deltagen and Pfizer, Pfizer shall be entitled to
perform site visits to Deltagen facilities involved in the Knockout Mouse
Projects to inspect the facilities for compliance with generally accepted
scientific and animal care procedures including, but not limited to those set
forth in Appendix A and Section 2.7 above.

* * *  Confidential material redacted and separately filed with the Commission.

                                       4
<PAGE>

5.       TERM AND TERMINATION

         5.1      The term of this Agreement shall commence on the Effective
Date and shall remain in effect until the earlier of either (a) termination of
this Agreement pursuant to the completion by Deltagen of all Milestones under
this Agreement or (b) two (2) years from the Effective Date; provided, however,
that all applicable obligations of Deltagen and Pfizer under this Agreement
shall remain in force with respect to any Knockout Mouse Project requested by
Pfizer and initiated by Deltagen which remains ongoing prior to the date set
forth in subsection (b) of this paragraph.

         5.2      * * *. Should Pfizer at any time during the Knockout Mouse
Project terminate the development and creation or completion of a specific
Knockout Mouse Project, Pfizer shall make the next Milestone Payment
corresponding to that work being conducted by Deltagen to complete such
Milestone at the time of termination, as if Deltagen had completed the
Milestone, regardless of whether such Milestone has been reached.

         5.3      Deltagen may terminate a Knockout Mouse Project upon
Deltagen's identification of technical difficulty beyond the reasonable control
of Deltagen which would prevent Deltagen from completing the Project using
commercially reasonable efforts, provided that Deltagen has informed Pfizer, in
writing, of the details of such technical difficulty, and the parties have had
an opportunity to discuss the circumstances to attempt to resolve the technical
difficulty in a reasonable manner. Pfizer is not entitled to a refund of any
past Milestone payments paid if a project is terminated as the result of
technical difficulty beyond the control of Deltagen.

         5.4      If either of the Parties is in breach of any obligation under
this Agreement, the party complaining of said breach shall give written notice
to the breaching party to remedy such breach. If the breach is not remedied
within 60 days following the receipt of such notice, the party complaining of
breach may terminate this Agreement upon written notice to the other party at
any time and with immediate effect. Any such termination will be without
prejudice to any other rights which the party complaining of breach may have as
a result of any breach of this Agreement.

6.       CONFIDENTIALITY

         6.1      Except as otherwise provided pursuant to Section 7.2, each
party shall treat all information which has been received from the other party
as strictly confidential ("Information"), and shall not make such Information
available to any third party without the express prior written consent of the
other party and only to use such Information for the purposes expressly provided
in this Agreement. For this purpose, employees and consultants of the parties
shall be bound by obligations of confidentiality and secrecy no less strict than
those set out herein and shall not be regarded as third Parties.

         6.2      The above obligations shall not apply or cease to apply to
Information which the recipient can show:

                                    (a) has become generally available to the
public other than through violation of this undertaking;

* * *  Confidential material redacted and separately filed with the Commission.

                                       5
<PAGE>

                                    (b) was already in the recipient's
possession prior to its acquisition from the disclosing party as reasonably
demonstrated by competent written evidence of the same.

                                    (c) was independently developed without use
of information received from the disclosing party as reasonably demonstrated by
competent written proof of the same.

                                    (d) has been received from a third party,
under no obligation to maintain the Information as confidential; or

                                    (e) is required to be disclosed by law or
court order, provided that notice is promptly delivered to the other party in
order to provide an opportunity to challenge or limit such disclosure.

A statutory obligation to disclose confidential information to governmental
authorities in connection with the Food and Drug Administration product
registration procedures is not subject to this secrecy obligation.

         6.3      This obligation of confidentiality shall survive the
expiration and/or termination of this Agreement for a period * * * years.

         6.4      Upon expiration or termination of this Agreement, or at any
time upon the disclosing party's written request, the receiving party shall
destroy, or at the written request of the disclosing party, deliver to the
disclosing party any and all Information (including copies) received or
generated hereunder, except that the receiving party may, for archival purposes,
maintain one copy of the Information in its confidential legal files for the
purpose of complying with this agreement.

7.       OWNERSHIP OF RIGHTS

         7.1      * * *.

         7.2      * * *

* * *  Confidential material redacted and separately filed with the Commission.

                                       6
<PAGE>

         7.3      * * *.

         7.4      * * *.

         7.5      * * *.

* * *  Confidential material redacted and separately filed with the Commission.

                                       7
<PAGE>

         7.6      After Pfizer has made all applicable Milestone Payments, or
other payments under Section 3.2 above, and upon delivery by Deltagen to
Pfizer's designated carrier (FOB), title shall transfer to Pfizer for each
Knockout Mouse Project and * * *.

8.       MISCELLANEOUS

         8.1      PUBLICATION. If Pfizer publishes any information, data or
material regarding the Knockout mice contemplated under this Agreement, Pfizer
shall acknowledge within the publication, the contribution of Deltagen to the
generation of such mouse or mice.

         8.2      FORCE MAJEURE. Neither party shall be liable for its failure
to perform its obligations under this Agreement due to contingencies beyond its
reasonable control, including but not limited to strikes, riots, wars, fire,
flood, accident, labor disputes, embargoes, inability to obtain export or import
license, acts of God, or acts in compliance with any governmental or state law,
regulation or other.

         8.3      AMENDMENTS. Amendments or modifications of this Agreement may
only be made by a written Agreement executed by both Parties.

         8.4      NOTICES. All notices required or permitted hereunder shall be
given in writing and sent postage prepaid by first class certified or registered
mail, or sent by a nationally recognized express courier service, or hand
delivered at the following addresses:

                  If to Deltagen:
                  * * *

                  If to Pfizer:
                  * * *

         8.5      REPRESENTATIONS AND WARRANTIES. Each party represents and
warrants that:

* * *  Confidential material redacted and separately filed with the Commission.

                                       8
<PAGE>

                  8.5.1    It will use commercially reasonable efforts to
complete its obligations under this Agreement in compliance with any and all
applicable federal, state, or local laws, and regulations.

                  8.5.2    * * *.

         8.6      * * *.

         8.7      APPLICABLE LAW AND VENUE. This Agreement shall be governed by
and construed in accordance with the laws of the State of Delaware as though
made and performed in said state without regard to its conflict of law
revisions.

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

         8.9      U.S. EXPORT LAWS AND REGULATIONS. Without limitation, each
party shall comply with all laws and regulations of the United States relating
to the export of biological materials, products and technical information.

         8.10     ENTIRE AGREEMENT. This Agreement contains the entire
understanding of the parties with respect to the subject matter hereof. All
express or implied Agreements and understandings, either oral or written,
heretofore made are expressly superseded by this Agreement.

         8.11     INDEPENDENT CONTRACTORS. It is expressly agreed that Deltagen
and Pfizer shall be independent contractors and that the relationship between
the two parties shall not constitute a partnership, joint venture or agency.
Neither Deltagen nor Pfizer shall have the authority to make any statements,
representations or commitments or any kind, or to take any action, which shall
be binding on the other, without the prior consent of the party to do so.

         8.12     WAIVER. The waiver by either party of any right hereunder or
the failure to perform or of a breach by the other party shall not be deemed a
waiver of any other right hereunder or of any other breach or failure by said
other party whether of a similar nature or otherwise.

* * *  Confidential material redacted and separately filed with the Commission.

                                       9
<PAGE>

AGREED AND ACCEPTED:

DELTAGEN. INC.                              PFIZER INC.

By /s/ William Matthews                     By /s/  George M. Milne, Jr.
   ---------------------------              ----------------------------

NAME       William Matthews                 NAME   George M. Milne, Jr.
      ------------------------              ----------------------------

TITLE      President                        TITLE    Vice President
      ------------------------              ----------------------------

DATE      December 17, 1998                 DATE     December 22, 1998
      ------------------------              ----------------------------

* * *  Confidential material redacted and separately filed with the Commission.

                                       10
<PAGE>

                                   APPENDIX A

[Three pages of milestone descriptions redacted and separately filed with the
Commission]

                                      * * *

* * *  Confidential material redacted and separately filed with the Commission.

                                       11
<PAGE>

                                   APPENDIX B

     FORM NOTIFICATION LETTER FOR INITIATION OF A NEW KNOCKOUT MOUSE PROJECT

                               (Template follows)

* * *  Confidential material redacted and separately filed with the Commission.

                                       12
<PAGE>

                               (Pfizer letterhead)

March 3, 1998

Bill Matthews, Ph.D.
President
Deltagen, Inc.
1031 Bing Street
San Carlos, CA 94070

Dear Bill,

This letter is to provide notice to Deltagen of Pfizer's request to Deltagen to
initiate work on a Knockout Mouse Project under the terms and conditions of the
Technology Agreement between Deltagen, Inc. and Pfizer, dated __________ (the
"Agreement"), including but not limited to, the confidentiality obligations of
the Agreement.

The Knockout Mouse Project to be initiated is described as follows:

The Pfizer contact scientist for technical information regarding the project
will be:

Pfizer requests that Deltagen begin to work to develop the above described
Knockout mouse on the terms and conditions of the above-referenced Agreement.

Sincerely,

Pfizer's Signatory

Agreed,

----------
Deltagen

* * *  Confidential material redacted and separately filed with the Commission.

                                       13<PAGE>

                                                                   EXHIBIT 10.19

           [CONFIDENTIAL TREATMENT REQUESTED. CONFIDENTIAL PORTIONS
      OF THIS AGREEMENT HAVE BEEN REDACTED AND HAVE BEEN SEPARATELY FILED
                             WITH THE COMMISSION.]

                DELTASELECT-TM- COLLABORATIVE SERVICES AGREEMENT

         This DeltaSelect-TM- Collaborative Services Agreement, including all
attachments hereto, (this "Agreement") is entered into as of December 16, 1999
(the "Agreement Date"), by and between DELTAGEN, INC., a Delaware corporation
having a place of business at 1003 Hamilton Avenue, California 94025
("DELTAGEN") and SCHERING-PLOUGH RESEARCH INSTITUTE, a Delaware corporation
having an address at 2015 Galloping Hill Road, Kenilworth, New Jersey 07033-1300
("SCHERING-PLOUGH").

WHEREAS, DELTAGEN possesses knowledge and experience in the research, creation,
design and generation of Knockout Mice (defined below); and

         WHEREAS, SCHERING-PLOUGH desires to engage DELTAGEN to generate
Knockout Mice for SCHERING-PLOUGH and DELTAGEN desires to undertake the
generation of such Knockout Mice for SCHERING PLOUGH on a * * * under the terms
and conditions set forth in this agreement.

         NOW THEREFORE, in consideration of the mutual covenants set forth
below, DELTAGEN and SCHERING-PLOUGH (individually "Party" and collectively
"Parties") agree as follows:

1.       DEFINITIONS.

         1.1      "Affiliate" shall mean any individual or entity directly or
indirectly controlling, controlled by or under common control with,
SCHERING-PLOUGH or DELTAGEN, as the case may be. For purposes of this Agreement,
the direct or indirect ownership of over fifty percent (50%) of the outstanding
voting securities of an entity, or the right to receive over fifty percent (50%)
of the profits or earnings of an entity shall be deemed to constitute control.
Such other relationship as in fact results in actual control over the
management, business and affairs of an entity shall also be deemed to constitute
control.

         1.2      "Budget" means the pricing and payment terms for a Knockout
Mice Project set forth in Attachment I attached hereto.

         1.3      "Confidential Information" means with respect to a Party
hereto (the "Disclosing Party"), collectively, all technical, financial and
business information of any kind whatsoever, and all tangible and intangible
embodiments thereof of any kind whatsoever, disclosed by the Disclosing Party to
the other Party hereto (the "Receiving Party") or obtained by the Receiving
Party through observation or examination of the foregoing, but only to the
extent such information or embodiment is maintained as confidential by the
Disclosing Party and is marked or otherwise identified as confidential when
disclosed to the Receiving Party or, in the case of information given verbally,
is identified as confidential in a written document provided to the Receiving
Party within thirty (30) days after verbal disclosure to the Receiving Party.

* * *  Confidential material redacted and separately filed with the Commission.

<PAGE>

         1.4      "Data" means all data or information generated under a
Knockout Mice Project under this Agreement, including but not limited to all
information, records, reports and other material(s) required to be generated,
collected or analyzed by DELTAGEN under a Knockout Mouse Project.

* * *  Confidential material redacted and separately filed with the Commission.

                                       2
<PAGE>

         1.5      * * *.

         1.6      "Effective Commencement Date" shall have the meaning set forth
in Section 2.3 below.

         1.7      * * *.

         1.8      "Knockout Mice" means mice generated under a Knockout Mice
Project pursuant to this Agreement * * *.

         1.9      "Knockout Mice Project" means a specific project to create and
generate Knockout Mice in accordance with the terms of a specific Scope of Work
under this Agreement.

         1.10     "Milestone" shall mean the milestones set forth on the Scope
of Work attached hereto.

         1.11     "Schering-Plough Representative" means the representative
identified in writing by SCHERING-PLOUG to DELTAGEN on a Scope of Work, as such
representative may be changed from time to time in writing by SCHERING-PLOUGH.

         1.12     * * *.

         1.13     "Scope of Work" means the work plan for a Knockout Mice
Project substantially in the form attached hereto as Attachment I.

         1.14     * * *.

         1.15     "Study Materials" means any samples or materials (including
chemical or biological) provided by SCHERING-PLOUGH to DELTAGEN for purposes of
a Knockout Mice Project under this Agreement.

2.       KNOCKOUT MICE PROJECTS

         2.1      INDIVIDUAL KNOCKOUT MICE PROJECTS. If SCHERING-PLOUGH wishes
to have DELTAGEN perform a Knockout Mice Project under this Agreement,
SCHERING-PLOUGH shall initiate such request for a Scope of Work by notifying
DELTAGEN in writing in the form set forth in Attachment II and providing a
description of the particular Knockout Mice Project requested as well as the
information set forth in Section 2.2 and the Scope of Work. DELTAGEN shall
evaluate each such request to determine whether such Knockout Mice Project

* * *  Confidential material redacted and separately filed with the Commission.

                                       3
<PAGE>

is feasible, if DELTAGEN requires technical or scientific modifications or if
DELTAGEN requires additional information to undertake such evaluation. If such
Knockout Mice Project in DELTAGEN's commercially reasonable discretion is not
feasible, DELTAGEN shall have the right (without penalty) to decline to
undertake such Knockout Mice Project. The terms of this Agreement, the Scope of
Work and the Budget shall form the entire agreement of the Parties with respect
to each Knockout Mice Project.

         2.2      INITIATION OF KNOCKOUT MICE PROJECTS. Prior to DELTAGEN's
initiation of each Knockout Mice Project, SCHERING-PLOUGH shall:

                  2.2.1    Identify to DELTAGEN in writing each Knockout Mice
Project to be initiated and agree in writing with DELTAGEN upon the Scope of
Work for such Knockout Mice Project;

                  2.2.2    Consult with and agree in writing with DELTAGEN
regarding the * * * for such Knockout Mice Project and any proposed
modifications to the Scope of Work for such Knockout Mice Project.
SCHERING-PLOUGH shall be solely responsible for providing to DELTAGEN the data
and information with respect to the specific gene sequence for such Knockout
Mice Project; and

                  2.2.3    Provide in writing to DELTAGEN all * * * reasonably
required by DELTAGEN to undertake such Knockout Mice Project (including
information to identify and generate probes under Milestones 1 and 2).

                  2.2.4    Transfer to DELTAGEN, to the extent possible,
any * * * to SCHERING-PLOUGH that may be suitable for DELTAGEN's screening of
mouse genomic libraries.

         2.3      COMMENCEMENT OF KNOCKOUT MICE PROJECT. Each Knockout Mice
Project conducted hereunder shall commence fifteen (15) days after written
agreement by both parties on a Scope of Work and DELTAGEN's receipt from
SCHERING-PLOUGH of all information and materials set forth in Section 2.2 above
relating to such Knockout Mice project (such date the "Effective Commencement
Date").

         2.4      PERFORMANCE. DELTAGEN shall use commercially reasonable
efforts to perform its obligations under this Agreement, provided that,
SCHERING-PLOUGH acknowledges and agrees that the performance of the Knockout
Mice Projects involves a number of technologically complex steps and that any
time periods for performance and the Scope of Work may be subject to change due
to potential technological difficulties encountered. DELTAGEN shall notify
SCHERING-PLOUGH of technical difficulties as soon as reasonably practicable
after such difficulties are encountered and the parties shall discuss and agree
in good faith upon methods to resolve such technical difficulties in a
reasonable manner.

         2.5      COMPLETION OF KNOCKOUT MICE PROJECT. Each Knockout Mice
Project shall be deemed complete upon SCHERING-PLOUGH's receipt of the Data for
such Knockout Mice Project under Section 9 below and DELTAGEN's completion of
the Milestones on the Scope of Work for such Knockout Mice Project.

* * *  Confidential material redacted and separately filed with the Commission.

                                       4
<PAGE>

         2.6      ADHERENCE TO SCOPE OF WORK. DELTAGEN shall perform those
activities described in the Scope of Work for each Knockout Mice Project.
Neither Party shall change or deviate from a Scope of Work without the prior
written consent of the other Party.

         2.7      CHANGES TO A KNOCKOUT MICE PROJECT. SCHERING-PLOUGH shall have
the right, from time to time, to propose modifications to the Scope of Work of a
Knockout Mice Project. If SCHERING-PLOUGH proposes to change any terms of a
Knockout Mice Project, including but not limited to the estimated time schedule
for such Knockout Mice Project, SCHERING-PLOUGH shall submit such
modification(s) in writing to DELTAGEN (the "Proposed Modification"). Such
Proposed Modification shall be implemented by the parties upon the written
agreement of both parties to such Proposed Modification (which agreement shall
not be unreasonably withheld) and a revised Budget for such Proposed
Modification. DELTAGEN shall have the right, in its commercially reasonable
discretion, to accept or reject such Proposed Modification based upon DELTAGEN's
good faith reasonable belief as to whether such proposed modifications would
alter DELTAGEN's technical, performance or financial obligations under a Scope
of Work.

         2.8      STANDARDS OF WORK AND ANIMAL CARE. With respect to each
Knockout Mice Project, DELTAGEN shall comply with all applicable IACUC standards
and good industry standards regarding the maintenance and care of the Knockout
Mice. * * * DELTAGEN shall replace any Knockout Mice that arrive at
SCHERING-PLOUGH diseased or dead (except for disease or death resulting from the
actions of SCHERING-PLOUGH's designated carrier). Upon the request of
SCHERING-PLOUGH, DELTAGEN shall promptly provide a written report to
SCHERING-PLOUGH concerning DELTAGEN's maintenance and care of the Knockout Mice.

3.       PAYMENTS AND BUDGET.

         3.1      BUDGET. SCHERING-PLOUGH shall pay to DELTAGEN the payments set
forth in the Budget for each Knockout Mice Project. Except as set forth in a
revised Budget under Section 3.2 below, such payments shall constitute full
payment for such Knockout Mice Project, including all labor, materials and
overhead and SCHERING-PLOUGH shall have no other payment obligations hereunder.

         3.2      PAYMENTS. For each Knockout Mice Project, DELTAGEN shall
submit invoices to SCHERING-PLOUGH for the payments set forth in the Scope of
Work and Budget upon DELTAGEN's completion of each Milestone set forth in the
Scope of Work and Budget (except for Milestone I - Construct Generation).
SCHERING-PLOUGH shall pay such invoices within thirty (30) days after receipt.
DELTAGEN shall include with each invoice a written representation of DELTAGEN's
completion of such Milestones and, where applicable, documentation showing such
completion.

         3.3      MILESTONE 1 - CONSTRUCT GENERATION. SCHERING-PLOUGH shall pay
to Deltagen within ten (10) days of the Agreement Date an initiation fee
of * * * (the "Initiation Fee") which shall consist of the * * * Milestone 1
payment for each of the * * * Knockout Mice Projects contemplated under this
Agreement. The Initiation Fee shall be nonrefundable, PROVIDED THAT, in the
event that this Agreement is terminated by SCHERING-PLOUGH pursuant to Section
11.4.1 due to a material breach of this Agreement by Deltagen, Deltagen shall
refund to SCHERING-

* * *  Confidential material redacted and separately filed with the Commission.

                                       5
<PAGE>

PLOUGH the Milestone I payments for each Knockout Mice Project that was not
commenced by Deltagen prior to the date of such termination.

4.       RIGHTS TO INVENTIONS.

         4.1      * * *.

         4.2      * * *.

         4.3      * * *.

         4.4      * * *.

* * *  Confidential material redacted and separately filed with the Commission.

                                       6
<PAGE>

5.       CONFIDENTIALITY.

         5.1      CONFIDENTIAL INFORMATION. Except as otherwise expressly
provided in this Agreement, each Party shall maintain in confidence the
Confidential Information of the other Party for a period of * * * years. Neither
Party shall use, disclose or grant the use of the other's Confidential
Information except on a need-to-know basis to those directors, officers,
employees, and agents, to the extent such disclosure is reasonably necessary in
connection with its activities as expressly authorized by this Agreement. To the
extent that disclosure is authorized by this Agreement, prior to such
disclosure, the Party wishing to disclose the other Party's Confidential
Information shall obtain the written agreement of any such person who is not
otherwise bound by confidentiality obligations at least as restrictive as the
obligations set forth in this Agreement, to hold in confidence and not make use
of the Confidential Information for any purpose other than those permitted by
this Agreement.

         5.2      PERMITTED DISCLOSURES. The nonuse and nondisclosure
obligations contained in this Article 5 shall not apply to the extent that (a)
the Receiving Party is required to disclose information by law, order, rule,
regulation or act of a governmental authority or agency or a court of competent
jurisdiction, PROVIDED THAT, the Receiving Party (i) shall reasonably notify the
Disclosing Party prior to any such disclosure to permit the Disclosing Party to
oppose such disclosure or to seek confidential treatment of such information and
(ii) if such disclosure is required, disclose only the minimum information
required to be disclosed in order to comply (as determined by counsel), whether
or not a protective order or other similar order is obtained by such Disclosing
Party; or (b) the Receiving Party can demonstrate that (i) the information was
public knowledge at the time of such disclosure by the Disclosing Party, or
thereafter became public knowledge, other than as a result of acts attributable
to Receiving Party in violation of this Agreement; or (ii) the information was
known by the Receiving Party (as shown by its written records) prior to the date
of disclosure to it by the Disclosing Party; or (iii) the information was
disclosed to the Receiving Party on an unrestricted basis from a third party not
under a duty of confidentiality of the Disclosing Party; or (iv) the information
was independently developed by employees or agents of the Receiving Party
without access to the Confidential Information of the

* * *  Confidential material redacted and separately filed with the Commission.

                                       7
<PAGE>

Disclosing Party.

         5.3      TERMS OF THIS AGREEMENT. Neither Party shall disclose any
terms or conditions of this Agreement (including without limitation the Budget)
to any third party without the prior consent of the other Party, except as
required by applicable law; PROVIDED HOWEVER, that either Party may disclose the
terms or conditions of this Agreement to a third party under an obligation of
confidentiality to such Party in connection with a proposed sale or in the event
of a proposed merger, change in control, consolidation, an equity investment by
such third party in such Party or other similar transaction. Notwithstanding the
foregoing, SCHERING-PLOUGH and DELTAGEN shall agree upon the substance of
information that can be used to describe the existence and/or terms of this
transaction in a press release and SCHERING-PLOUGH and DELTAGEN shall have the
right to disclose such information, as such information may be modified by
mutual agreement of the parties from time to time.

         5.4      NO LICENSE. Except as expressly provided in this Agreement,
nothing herein shall be construed as giving either Party any license, right,
title or interest in or ownership, whether express or implied, of the other
Party's Confidential Information. Upon termination of this Agreement or a
particular Knockout Mice Project as provided in Article 11, or upon either
Party's request, each Party shall return all Confidential Information of the
other Party and/or destroy any portion of any documents, computer records, notes
and other material retained by such Party containing the Confidential
Information of the other Party. However, each Party may retain one copy of such
Confidential Information in its legal files to be used only for interpretation
of and compliance with this Agreement.

6.       REPRESENTATIONS AND WARRANTIES.

         6.1      Each Party hereby represents and warrants to the other Party
as follows:

                  6.1.1    CORPORATE EXISTENCE. Such Party is a corporation duly
organized, validly existing and in good standing under the laws of the state in
which it is incorporated.

                  6.1.2    AUTHORIZATION AND ENFORCEMENT OF OBLIGATIONS. Such
Party (a) has the corporate power and authority and the legal right to enter
into this Agreement and to perform its obligations hereunder, and (b) has taken
all necessary corporate action on its part to authorize the execution and
delivery of this Agreement and the performance of its obligations hereunder.
This Agreement has been duly executed and delivered on behalf of such Party, and
constitutes a legal, valid, binding obligation, enforceable against such Party
in accordance with its terms.

                  6.1.3    NO CONSENTS. All necessary consents, approvals and
authorizations of all governmental authorities and other persons required to be
obtained by such Party in connection with this Agreement have been obtained.

                  6.1.4    NO CONFLICT. The execution and delivery of this
Agreement and the performance of such Party's obligations hereunder (a) do not
conflict with or violate any requirement of applicable laws or regulations, and
(b) do not conflict with, result in a breach of

* * *  Confidential material redacted and separately filed with the Commission.

                                       8
<PAGE>

any of the terms and provisions of, or constitute a default under, any
contractual obligation of it, and (c) do not conflict with or result in a breach
of any of the terms and provisions of its charter or operative documents or
bylaws.

                  6.1.5    COMPLIANCE WITH LAWS. Such Party shall comply with
all applicable material laws and regulations related to its activities
contemplated under this Agreement.

         6.2      * * *.

         6.3      * * *.

         6.4      * * *.

         6.5      * * *.

* * *  Confidential material redacted and separately filed with the Commission.

                                       9
<PAGE>

7.       REPORTING.

         DELTAGEN shall deliver via overnight delivery service (or other
reasonable means agreed to by the parties) to the SCHERING-PLOUGH Representative
all reports required to be delivered in connection with a Knockout Mice Project.

8.       RECORD RETENTION, INSPECTIONS AND COOPERATION.

         8.1      At SCHERING-PLOUGH'S request, DELTAGEN shall maintain all
written Data and reports from each Knockout Mice Project for a period of one (1)
year from the date of completion of such Knockout Mice Project. At the
expiration of such one (1) year period, SCHERING-PLOUGH, at SCHERING-PLOUGH's
cost and expense, shall arrange with DELTAGEN for delivery of such Data to
SCHERING-PLOUGH or DELTAGEN may dispose of such written Data sixty (60) days
after providing written notice of the same to SCHERING-PLOUGH.

         8.2      If a federal, state or local government authority conducts or
gives notice of its intent to conduct an inspection or takes regulatory action
with respect to a Knockout Mice Project conducted under this Agreement, the
Party learning thereof shall reasonably notify in writing the other Party
thereof and each Party shall provide the other with any information reasonably
required in connection therewith.

9.       DATA.

         Notwithstanding the provisions of Section 8, for each Knockout Mice
Project, DELTAGEN shall prepare and submit to SCHERING-PLOUGH or its designee
the Data set forth under the applicable Scope of Work with respect to a
particular Knockout Mice Project within forty-five (45) days after (i) the date
of termination or completion of the Milestones on the Scope of Work for such
Knockout Mice Project or (ii) the date that SCHERING-PLOUGH requests delivery of
such Data.

10.      SUBCONTRACTING AND INDEPENDENT CONTRACTOR.

         10.1     SUBCONTRACTING. SCHERING-PLOUGH is aware that certain Knockout
Mice Projects may require DELTAGEN to subcontract to third parties portions of
the work required under a Scope of Work. SCHERING-PLOUGH shall be deemed to have
approved such subcontracting on the following terms and conditions: (i) DELTAGEN
shall not be allowed or authorized to make any representations relating to
SCHERING-PLOUGH without the prior written consent of SCHERING-PLOUGH; and (ii)
such third party subcontractor shall be subject to the terms and conditions of
this Agreement. Prior to subcontracting any work contemplated by a Knockout Mice
Project, DELTAGEN shall notify SCHERING-PLOUGH of the intended third party
subcontractor and SCHERING-PLOUGH shall be provided with fourteen (14) days in
which to object to the use of a particular subcontractor. If SCHERING-PLOUGH
does not object to the use of a particular subcontractor within such fourteen
(14) day period, DELTAGEN may subcontract such work under the Scope of Work to
such third party subcontractor. If SCHERING-PLOUGH does object to the use of a
particular subcontractor, in its sole discretion, DELTAGEN shall be prohibited
from using such subcontractor to perform work under this

* * *  Confidential material redacted and separately filed with the Commission.

                                       10
<PAGE>

Agreement.

         10.2     INDEPENDENT CONTRACTOR. DELTAGEN shall perform its obligations
under this Agreement as an independent contractor and nothing contained herein
shall be construed to be inconsistent with that relationship or status. Neither
Party, nor their officers, directors, employees or agents shall be considered
employees or agents of the other Party and shall not be entitled to participate
in any of the other Party's benefit plans, programs, employment policies, or
workers' compensation insurance. This Agreement shall not constitute, create, or
in any way be interpreted as a joint venture, partnership or business
organization of any kind. Neither Party shall have the authority to bind the
other Party to any agreement whatsoever.

11.      TERM AND TERMINATION.

         11.1     TERM. This Agreement shall commence on the Agreement Date and
remain in fall force and effect until the later of (a) two (2) years after the
Agreement Date, or (b) the completion by DELTAGEN of all Milestones under any
Knockout Mice Projects commenced under this Agreement, unless earlier terminated
as provided below in this Article 11.

         11.2     * * *.

         11.3     TERMINATION BY DELTAGEN. DELTAGEN shall have the right to
terminate a Knockout Mice Project upon DELTAGEN's identification of an item or
circumstance under Section 2.4 that would prevent DELTAGEN from completing such
Knockout Mice Project using commercially reasonable efforts by providing thirty
(30) days written notice to SCHERING-PLOUGH, which notice shall contain the
basis for such termination.

         11.4     TERMINATION BY EITHER PARTY.

                  11.4.1 MATERIAL DEFAULT. Except as otherwise provide in
Article 14 below, this Agreement or a Knockout Mice Project may be terminated by
either Party upon any material breach of this Agreement by the other Party,
provided that any breaching Party shall be given not less than sixty (60) days
prior written notice of such breach and the opportunity to cure such breach
during such period.

                  11.4.2 BANKRUPTCY. This Agreement or a Knockout Mice Project
may be immediately terminated by either Party if the other Party is dissolved or
liquidated, files or has filed against it a petition in bankruptcy or has a
receiver appointed for a substantial part of its assets.

         11.5     RIGHTS AND OBLIGATIONS AFTER NOTICE OF TERMINATION.

                  11.5.1 TERMINATION BY SCHERING-PLOUGH * * * OR BANKRUPTCY. If
this Agreement or a Knockout Mice Project is terminated by SCHERING-PLOUGH
pursuant to Section 11.2 or terminated by DELTAGEN pursuant to Section 11.4,
DELTAGEN shall have the right to cease further work on applicable Knockout Mice
Projects and to cancel, if permitted under the terms of applicable agreements,
any third party obligations.

* * *  Confidential material redacted and separately filed with the Commission.

                                       11
<PAGE>

Within thirty (30) days after DELTAGEN's cessation of work on such Knockout Mice
Project(s), DELTAGEN shall provide SCHERING-PLOUGH with a written statement of
all work performed by it through termination, including any non-cancelable costs
or expenses incurred by DELTAGEN prior to termination. DELTAGEN shall invoice
SCHERING-PLOUGH for all Milestones completed by DELTAGEN and for all reasonable
non-cancelable costs or expenses and if such notice is received by DELTAGEN
after work has commenced but prior to DELTAGEN's completion of work under a
Milestone, DELTAGEN shall invoice SCHERING-PLOUGH for payment of such
uncompleted Milestone as if DELTAGEN had completed such Milestone and
SCHERING-PLOUGH shall pay DELTAGEN for such uncompleted Milestone. DELTAGEN
shall deliver to SCHERING-PLOUGH all deliverables prepared or completed by
DELTAGEN at the time of such cessation of work and all unused Study Materials
and Data within sixty (60) days of DELTAGEN's notice of termination or receipt
by DELTAGEN of SCHERING-PLOUGH's notice of termination.

                  11.5.2 TERMINATION BY SCHERING-PLOUGH FOR BANKRUPTCY OF
DELTAGEN OR BY DELTAGEN FOR DELTAGEN'S INABILITY TO COMPLETE MILESTONE. If this
Agreement or a Knockout Mice Project is terminated by DELTAGEN pursuant to
Section 11.3 or by SCHERING-PLOUGH pursuant to Section 11.4.2 above, DELTAGEN
shall deliver all deliverables prepared or completed by DELTAGEN at the time of
such termination, all unused Study Materials and all Data to SCHERING-PLOUGH
within sixty (60) days of DELTAGEN'S notice of termination or receipt by
DELTAGEN of SCHERING-PLOUGH's notice of termination. DELTAGEN shall provide
SCHERING-PLOUGH with a written itemized statement of all work performed by
DELTAGEN through the date of termination (including any Milestones actually
completed by DELTAGEN) and SCHERING-PLOUGH shall pay such invoiced amount within
thirty (30) days of receipt of such statement.

                  11.5.3 TERMINATION BY SCHERING-PLOUGH FOR BREACH BY DELTAGEN.
If this Agreement or a Knockout Mice Project is terminated by SCHERING-PLOUGH
pursuant to Section 11.4.1 above, DELTAGEN shall deliver all deliverables
prepared or completed by DELTAGEN at the time of such termination, all unused
Study Materials and all Data to SCHERING-PLOUGH within sixty (60) days of
receipt by DELTAGEN of notice of termination. DELTAGEN shall provide
SCHERING-PLOUGH with a written itemized statement of all work performed by
DELTAGEN through the date of termination (including any Milestones actually
completed by DELTAGEN) and SCHERING-PLOUGH shall pay such invoiced amount (or
portion thereof that is not reasonably the subject of such breach) within thirty
(30) days of receipt of such statement.

         11.6     EFFECT OF EXPIRATION OR TERMINATION. Expiration or termination
of this Agreement shall not relieve the parties of any obligation accruing prior
to such expiration or termination. The provisions of Sections 6.4, 6.5 and
Articles 4, 5 and 12 shall survive any expiration or termination of this
Agreement.

12.      INDEMNIFICATION.

         12.1     * * *.

* * *  Confidential material redacted and separately filed with the Commission.

                                       12
<PAGE>

         12.2     * * *.

         12.3     PROCEDURE. A Party (the "Indemnified Party") which intends to
                  claim indemnification under this Article 12, shall promptly
                  notify the other Party (the "Indemnifying Party") of any Claim
                  with respect to which the Indemnified Party intends to claim
                  such indemnification. The Indemnifying Party shall have the
                  right to assume the defense of such Claim with counsel
                  selected by the Indemnifying Party; PROVIDED, HOWEVER, that
                  the Indemnified Party shall have the right to retain its own
                  counsel and the fees and expenses shall be paid by the
                  Indemnifying Party only if representation of the Indemnified
                  Party by the counsel retained by the Indemnifying Party would
                  be inappropriate due to actual or potential differing
                  interests between the Indemnified Party and any other party
                  represented by such counsel in such proceedings. The indemnity
                  obligations under this Article 12 shall not apply to amounts
                  paid in settlement of any Liability if such settlement is
                  effected without the consent of the Indemnifying Party, which
                  consent shall not be withheld unreasonably. The failure of the
                  Indemnified Party to promptly notify the Indemnifying Party of
                  a potential Claim shall not constitute a waiver of, or result
                  in the loss of, such Party's right to indemnification under
                  this Section 12.3, except to the extent that the Indemnifying
                  Party's rights and/or its ability to defend such Claim is
                  prejudiced by the Indemnified Party's failure to notify the
                  Indemnifying Party of such Claim within a reasonable time
                  after the commencement of any action. The Indemnifying Party
                  may not settle the action or otherwise consent to an adverse
                  judgment in such action that diminishes the rights or
                  interests of the Indemnified Party without the express written
                  consent of the Indemnified Party, which consent shall not be
                  withheld unreasonably. The Indemnified Party, its employees
                  and agents, shall cooperate fully with the Indemnified Party
                  and its legal representatives in the investigation of any
                  Claim covered by this indemnification.

13.      TRADEMARKS AND PUBLICITY.

         Except as set forth in Section 5.3 above, each Party agrees not to
identify the other Party or any Affiliate of the other Party in any promotion
advertising or other promotion materials to be disseminated to the public, or to
use any trademark, service mark, trade name or symbol of the other Party or any
Affiliate of the other Party without the express written consent of the other
Party.

* * *  Confidential material redacted and separately filed with the Commission.

                                       13
<PAGE>

14.      DELAYS OR FORCE MAJEURE.

         14.1     FORCE MAJEURE. Neither Party shall be liable for the failure
or delay to perform its obligations under this Agreement or a Knockout Mice
Project if such failure or delay is caused by or results from causes beyond such
Party's reasonable control, including but not limited to strikes or other labor
disturbances, embargoes, acts of God, omissions or delays in acting by any
governmental authority or the other party, lockouts, riots, wars, fires, floods,
earthquakes or storms. A Party claiming a right to excused performance under
this Section 14.1 shall immediately notify the other Party in writing of the
extent of its inability to perform, which notice shall specify the occurrence
beyond its reasonable control that prevents such performance, and such Party
shall exert reasonable efforts to eliminate, cure and overcome any such causes
and to promptly resume performance of its obligations under this Agreement.

         14.2     DELAY. If SCHERING-PLOUGH delays in performing its obligations
under a Knockout Mice Project for any reason, the estimated date that DELTAGEN
is targeted to complete its duties and obligations as described in the
applicable Scope of Work shall be extended by the period of time corresponding
to the delay.

15.      NOTICES.

         Any notice required or permitted to be given hereunder by one of the
parties hereto to the other party shall be in writing and delivered by any
lawful means to the address of the other party set forth below or at such other
address as either Party hereto may designate in writing. If sent by facsimile
letter, notice shall be deemed given when the transmission is completed if the
sender has a confirmed transmission report. Any notice sent by facsimile must
also be sent by mail or overnight courier or delivered by hand.

IF TO DELTAGEN:

* * *

* * *  Confidential material redacted and separately filed with the Commission.

                                       14
<PAGE>

IF TO SCHERING-PLOUGH:

* * *
16.      MISCELLANEOUS

         16.1     * * *.

         16.2     AMENDMENTS, WAIVER. No provision of this Agreement, the Budget
or the Scope of Work may be amended, modified, revoked, or waived except in
writing signed and delivered by an authorized officer of each Party. Either
Party's failure to require the other Party to comply with the provisions of this
Agreement shall not be deemed a waiver of such provision or any other provision
of this Agreement.

         16.3     VALIDITY. If any clause, section or paragraph of this
Agreement is determined by a court of competent jurisdiction to be illegal,
invalid or unenforceable, it will be deemed severed from the remainder of this
Agreement and will have no effect on the legality, validity or enforceability of
the remaining provisions.

         16.4     HEADINGS. The paragraph headings of this Agreement are merely
for the convenience of the parties and are not to be construed as modifying or
changing the obligations or conditions expressed in this Agreement.

         16.5     ENTIRETY. This Agreement (including the Attachments hereto)
represents the entire understanding as of the Agreement Date hereof between the
parties with respect to the matter hereof and supersedes all prior agreements,
negotiations, understandings, representations, statements and writings between
the parties relating thereto.

         16.6     CONFLICT WITH SCOPE OF WORK OR BUDGET. If any terms of this
Agreement are in conflict with any terms of any Scope of Work or Budget, the
terms of this Agreement shall govern.

         16.7     COUNTERPARTS. This Agreement may be executed in several
counterparts, each of which shall be deemed an original but all of which shall
constitute one and the same instrument.

         16.8     GOVERNING LAW. This Agreement shall be governed by and
construed in accordance with the laws of the State of California, without regard
to its conflicts of law principles.

* * *  Confidential material redacted and separately filed with the Commission.

                                       15
<PAGE>

         16.9     FURTHER ACTIONS. Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all other acts, as may be necessary
or appropriate in order to carry out their obligations under this Agreement.

         IN WITNESS WHEREOF, the Parties hereto through each of their respective
duly authorized representatives have caused this Agreement to be executed as of
the Agreement Date.

SCHERING-PLOUGH RESEARCH INSTITUTE              DELTAGEN, INC.

By: /s/ Jonathan Spicehandler, M.D.             By: /s/ William Matthews

Name: Jonathan Spicehandler, M.D.               Name: William Matthews

Title:  President                               Title:  Chief Executive Officer

           12/16/99

* * *  Confidential material redacted and separately filed with the Commission.

                                       16
<PAGE>

                                  ATTACHMENT I

                                      * * *

 [3 pages of milestones and work descriptions redacted and filed separately
with the Commission]

* * *  Confidential material redacted and separately filed with the Commission.

                                       17
<PAGE>

                                 ATTACHMENT 11

    FORM NOTIFICATION LETTER FOR INITIATION OF A NEW KNOCKOUT MOUSE PROJECT

                               (Template follows)

* * *  Confidential material redacted and separately filed with the Commission.

                                       18
<PAGE>

                          (SCHERING-PLOUGH letterhead)

__________, __, _____

William Matthews, Ph.D.
President
Deltagen, Inc.
1003 Hamilton Avenue
Menlo Park, CA 94025

Dear Bill,

This letter is to provide notice to Deltagen of Schering-Plough's request to
Deltagen to initiate work on a Knockout Mouse Project under the terms and
conditions of the DeltaSelect-TM- Collaborative Services Agreement between
Deltagen, Inc. and Schering-Plough, dated ____________ (the "Agreement"),
including but not limited to, the confidentiality obligations of the Agreement.

The Knockout Mice Project to be initiated is described as follows:

The Schering-Plough contact scientist for technical information regarding the
project will be:

Schering-Plough requests that Deltagen begin to work to develop the above
described Knockout Mice on the terms and conditions of the above-referenced
Agreement.

Sincerely,

SCHERING-PLOUGH RESEARCH INSTITUTE'S Signatory

Agreed,

-------------------
Deltagen, Inc.

* * *  Confidential material redacted and separately filed with the Commission.

                                       19

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