<PAGE>


                                                                    EXHIBIT 10.1









                               DNA SCIENCES, INC.


                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT


                                DECEMBER 22, 2000




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                                TABLE OF CONTENTS

                                                                        PAGE


SECTION 1   DEFINITIONS; AMENDMENT AND WAIVER.............................2

     1.1    "Commission"..................................................2
     1.2    "Common Stock"................................................2
     1.3    "Exchange Act"................................................2
     1.4    "Holder"......................................................2
     1.5    "Initiating Holders"..........................................2
     1.6    "Preferred"...................................................2
     1.7    "Registrable Securities"......................................2
     1.8    The terms "register," "registered" and "registration".........3
     1.9    "Registration Expenses".......................................3
     1.10   "Securities"..................................................3
     1.11   "Securities Act"..............................................3
     1.12   "Selling Expenses"............................................3
     1.13   Amendment of Prior Rights Agreement;
               Waiver of Right of First Offer.............................3

SECTION 2   INFORMATION RIGHTS............................................3
     2.1    Financial Information.........................................3
     2.2    Assignment of Rights..........................................4
     2.3    Termination...................................................4

SECTION 3   RIGHTS OF FIRST OFFER ON NEW ISSUANCES........................4
     3.1    Rights of First Offer.........................................4
     3.2    Termination...................................................6

SECTION 4   REGISTRATION RIGHTS...........................................6
     4.1    Requested Registration........................................6
     4.2    Company Registration..........................................8
     4.3    Registration on Form S-3......................................9
     4.4    Limitations on Subsequent Registration Rights.................9
     4.5    Expenses of Registration.....................................10
     4.6    Registration Procedures......................................10
     4.7    Indemnification..............................................11
     4.8    Information by Holder........................................13


                                       i.

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                                TABLE OF CONTENTS
                                   (CONTINUED)

                                                                        PAGE



     4.9    Rule 144 Reporting...........................................13
     4.10   Transfer of Registration Rights..............................14
     4.11   Termination..................................................14
     4.12   Lockup Agreement.............................................14

SECTION 5   LEGENDS......................................................14
     5.1    Legends......................................................14

SECTION 6   MISCELLANEOUS................................................15
     6.1    Governing Law................................................15
     6.2    Entire Agreement; Amendment..................................15
     6.3    Aggregation..................................................15
     6.4    Notices, etc.................................................15
     6.5    Additional Purchasers........................................16
     6.6    Severability.................................................16
     6.7    Counterparts.................................................16




                                       ii.


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                               DNA SCIENCES, INC.
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

     THIS AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT (this "AGREEMENT") is
made as of this 22nd day of December, 2000 by and among DNA Sciences, Inc., a
Delaware corporation (the "COMPANY"), the holders of the Company's Series A
Preferred Stock set forth on Exhibit A hereto (the "SERIES A HOLDERS"), the
holders of the Company's Series B Preferred Stock set forth on Exhibit A hereto
(the "SERIES B HOLDERS"), the holders of the Company's Series C Preferred Stock
set forth on Exhibit A hereto (the "SERIES C HOLDERS"), the holders of the
Company's Series C-1 Preferred Stock set forth on Exhibit A hereto (the "Series
C-1 Holders") and the holders of the Company's Series D Preferred Stock set
forth on Exhibit A hereto (the "SERIES D HOLDERS"). The Series A Holders, the
Series B Holders, the Series C Holders, the Series C-1 Holders and the Series D
Holders shall be referred to hereinafter individually as an "INVESTOR" and
collectively as the "INVESTORS."


                                    RECITALS

     A. The Company, the Series A Holders, the Series B Holders and certain of
the Series C Holders have previously entered into that certain Amended and
Restated Investor Rights Agreement dated as of December 15, 2000 (the "PRIOR
RIGHTS AGREEMENT"), pursuant to which the Company granted the Series A Holders,
the Series B Holders and the Series C Holders certain rights;

     B. The Company and PPGx, Inc., a Delaware corporation ("PPGx"), entered
into that certain Agreement and Plan of Merger and Reorganization, by and among
the Company, PIPO Acquisition Corp., a Delaware corporation and a wholly owned
subsidiary of the Company ("MERGER SUB"), and PPGx, dated as of December 17,
2000 (the "REORGANIZATION AGREEMENT"), pursuant to which Merger Sub was merged
with and into PPGx and PPGx became the surviving corporation and a wholly owned
subsidiary of the Company;

     C. Pursuant to the Reorganization Agreement, the Company issued two million
nine hundred and fifty-seven thousand one hundred (2,957,100) shares of its
Series D Preferred to the Series D Holders;

     D. A condition to the Series D Holders' obligations under the
Reorganization Agreement is that the Company extend to them certain information
and registration rights and other rights with respect to the Company's Series D
Preferred as set forth below, and

     E. The Series A Holders, the Series B Holders and certain of the Series C
Holders are holders of at least a majority of the Registrable Securities of the
Company (as defined in the Prior Rights Agreement), and desire to amend and
restate the Prior Rights Agreement in its entirety and accept the rights created
pursuant to this Agreement in lieu of the rights granted to them under the Prior
Rights Agreement.

     NOW, THEREFORE, in consideration of the mutual promises, representations,
warranties, covenants and conditions set forth in this Agreement and in the
Reorganization Agreement, the parties mutually agree as follows:


                                       1.
<PAGE>


                                    SECTION 1

                        DEFINITIONS; AMENDMENT AND WAIVER

     As used in this Agreement, the following terms shall have the following
respective meanings:

     1.1 "COMMISSION" shall mean the Securities and Exchange Commission of the
United States or any other U.S. federal agency at the time administering the
Securities Act.

     1.2 "COMMON STOCK" shall mean shares of the Company's Common Stock, par
value $.001 per share.

     1.3 "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934, as
amended.

     1.4 "HOLDER" shall mean each of the Investors (and their transferees as
permitted by Section 4.10) holding Registrable Securities or securities
convertible into Registrable Securities.

     1.5 "INITIATING HOLDERS" shall mean Holders who in the aggregate hold
greater than fifty percent (50%) of the Preferred.

     1.6 "PREFERRED" shall mean shares of the Company's Series A preferred
stock, par value $.001 per share (the "SERIES A PREFERRED"), the Company's
Series B preferred stock, par value $.001 per share (the "SERIES B Preferred"),
including shares of Series B PREFERRED issuable upon exercise of: (i) that
certain warrant entered into by and between the Company and Cooley Godward LLP
on March 16, 2000; (ii) that certain warrant entered into by and between the
Company and GATX Ventures, Inc. on October 6, 2000 (the "GATX WARRANT"); and
(iii) that certain warrant entered into by and between the Company and TBCC
Funding Trust II on October 6, 2000 (the "TBCC WARRANT"), the Company's Series C
preferred stock, par value $.001 per share (the "SERIES C PREFERRED"), the
Company's Series C-1 preferred stock, par value $.001 per share (the "SERIES C-1
PREFERRED") and the Company's Series D preferred stock, par value $.001 per
share (the "SERIES D PREFERRED").

     1.7 "REGISTRABLE SECURITIES" shall mean any shares of Common Stock issued
or issuable (i) on conversion of the Preferred, (ii) upon exercise by the
Investors of their preemptive rights as provided in Section 3 of this Agreement,
(iii) upon exercise by the Investors of their right of first offer rights
pursuant to the Amended and Restated Right of First Refusal and Co-Sale
Agreement of even date herewith, and (iv) any shares of Common Stock issued or
issuable in respect of such Common Stock upon any stock



                                       2.
<PAGE>


split, stock dividend, recapitalization or similar event. Shares of Common Stock
or other securities shall only be treated as Registrable Securities if they have
not been sold to or through a broker or dealer or underwriter in a public
distribution or a public securities transaction. Solely for the purposes of
Section 4.2 of this Agreement, the Company shall treat the Warrant Shares, as
defined in the GATX Warrant and the TBCC Warrant, as Registrable Securities.

     1.8 THE TERMS "REGISTER," "REGISTERED" AND "REGISTRATION" refer to a
registration effected by preparing and filing a registration statement in
compliance with the Securities Act, and the declaration or ordering of the
effectiveness of such registration statement.

     1.9 "REGISTRATION EXPENSES" shall mean all expenses, except as otherwise
stated below, incurred by the Company in complying with Sections 4.1, 4.2, and
4.3 hereof, including, without limitation, all registration, qualification and
filing fees, printing expenses, escrow fees, fees and disbursements of counsel
for the Company (and fees and disbursements of one special counsel for Holders,
if any), blue sky fees and expenses and the expense of any special audits
incident to or required by any such registration (but excluding the compensation
of regular employees of the Company, which shall be paid in any event by the
Company).

     1.10 "SECURITIES" shall mean Common Stock or Preferred.

     1.11 "SECURITIES ACT" shall mean the Securities Act of 1933, as amended, or
any similar United States federal statute and the rules and regulations of the
Commission thereunder, all as the same, which shall be in effect at the time.

     1.12 "SELLING EXPENSES" shall mean all underwriting discounts, selling
commissions and stock transfer taxes applicable to the securities registered by
the Holders.

     1.13 AMENDMENT OF PRIOR RIGHTS AGREEMENT; WAIVER OF RIGHT OF FIRST OFFER.
Effective and contingent upon execution of this Agreement by the Company and the
holders of a majority of the Registrable Securities, as that term is defined in
the Prior Rights Agreement, and upon closing of the transactions contemplated by
the Reorganization Agreement, the Prior Rights Agreement is hereby amended and
restated in its entirety to read as set forth in this Agreement, and the Company
and the Investors hereby agree to be bound by the provisions hereof as the sole
agreement of the Company and the Investors with respect to registration rights
of the Company's securities and certain other rights, as set forth herein. The
Series A Holders, the Series B Holders and the Series C Holders hereby waive the
right of first offer, including the notice requirements, set forth in the Prior
Rights Agreement with respect to the issuance of Series D Preferred, except to
the extent that a Series A Holder, a Series B Holder or a Series C Holder is
receiving Series D Preferred, as set forth in the Reorganization Agreement.



                                       3.
<PAGE>

                                   SECTION 2

                               INFORMATION RIGHTS

     2.1 FINANCIAL INFORMATION. The Company will provide each Investor the
following reports for so long as the Investor is a holder of a minimum of ten
thousand (10,000) shares of Registrable Securities (as adjusted for stock splits
and combinations):

          (a) As soon as practicable after the end of each fiscal year, and in
any event within one hundred twenty (120) days thereafter, consolidated balance
sheets of the Company and its subsidiaries, if any, as of the end of such fiscal
year, and consolidated statements of income, stockholders' equity and cash flows
of the Company and its subsidiaries, if any, for such year, prepared in
accordance with generally accepted accounting principles and setting forth in
each case in comparative form the figures for the previous fiscal year, and all
in reasonable detail and audited by independent public accountants of national
standing selected by the Company.

          (b) As soon as practicable after the end of each month and fiscal
quarter, and in any event within thirty (30) days and forty-five (45) days,
respectively, thereafter, a consolidated balance sheet of the Company and its
subsidiaries, if any, as of the end of each such period, consolidated statements
of income, consolidated statements of changes in financial condition, a
consolidated statement of cash flow of the Company and its subsidiaries and a
statement of stockholders' equity for such period and for the current fiscal
year to date, and setting forth in each case in comparative form the figures for
corresponding periods in the previous fiscal year, and setting forth in
comparative form the budgeted figures, prepared in accordance with generally
accepted accounting principles (other than for accompanying notes), subject to
changes resulting from year-end audit adjustments, all in reasonable detail and
signed by the principal financial or accounting officer of the Company.

          (c) As soon as practicable after its adoption by the Board of
Directors of the Company (the "BOARD OF DIRECTORS"), a copy of the annual
operating plan of the Company for the next fiscal year and an annual budget for
the next fiscal year of the Company containing profit and loss projections, cash
flow projections and capital expenditures, all on a monthly basis.

     2.2 ASSIGNMENT OF RIGHTS. The rights granted pursuant to Section 2.1 may be
assigned or otherwise conveyed by an Investor to a constituent partner or an
affiliate of the Investor or to a transferee who acquires (i) at least ten
thousand (10,000) shares of Preferred (as adjusted for stock splits and
combinations), or (ii) all shares of Preferred held by such transferor.
Notwithstanding the foregoing, the rights granted pursuant to Section 2.1 may
not be assigned or otherwise conveyed to a competitor of the Company, as
reasonably determined by the Board of Directors excluding any director with an
interest in such transferee. The Investor shall provide the Company with written
notice of any assignment or conveyance of the rights granted pursuant to Section
2.1.

     2.3 TERMINATION. The provisions of Sections 2 and 3, including information
rights, rights of first offer and miscellaneous covenants, shall terminate upon
the closing of a firmly underwritten public offering pursuant to an effective
registration statement under the Securities Act covering any securities of the
Company.

                                       4.
<PAGE>


                                   SECTION 3

                     RIGHTS OF FIRST OFFER ON NEW ISSUANCES

     3.1 RIGHTS OF FIRST OFFER. The Company hereby grants to each Investor the
right of first offer to purchase such Investor's pro rata portion of New
Securities (as defined in Section 3.1(a)) that the Company may, from time to
time, propose to sell and issue. Such Investor's pro rata portion, for purposes
of this right of first offer, is the ratio of the number of shares of Common
Stock held by such Investor (including Common Stock issuable upon conversion of
securities convertible into Common Stock held by such Investor, including the
Preferred) bears to the total number of shares of Common Stock outstanding at
the time of issuance of such New Securities (including Common Stock issuable
upon conversion of all outstanding securities convertible into Common Stock,
including the Preferred). This right of first offer shall be subject to the
following provisions:

          (a) "NEW SECURITIES" shall mean any Common Stock, whether now
authorized or not, any rights, options, or warrants to purchase said Common
Stock and securities of any type whatsoever that are, or may become, convertible
into Common Stock; PROVIDED, HOWEVER, that New Securities shall not include (i)
shares of Common Stock issued upon conversion of the Preferred; (ii) securities
issued pursuant to the acquisition of another corporation by the Company by
merger, purchase of substantially all of the assets or other reorganization;
(iii) up to four million five hundred thousand (4,500,000) shares of Common
Stock (or related options) issued to employees, officers, directors, consultants
or other persons performing services for the Company pursuant to any stock
offering, plan or other arrangement approved by the Board of Directors; (iv)
securities issued to financial institutions in connection with the extension of
credit to the Company or in connection with the lease of equipment and in both
cases for other than equity financing purposes; (v) securities issued to any
third party in connection with participation in a strategic bona fide alliance
or other corporate partner transaction with the Company approved by the Board of
Directors for purposes which are not primarily equity financing; (vi) securities
issued pursuant to the acquisition or license of technology, software or other
intellectual property rights; (vii) shares of Common Stock issued in connection
with any stock split, stock dividend or recapitalization by the Company; or
(viii) shares of Series D Preferred issued pursuant to the Reorganization
Agreement.

          (b) In the event that the Company proposes to issue New Securities, it
shall give each Investor at least thirty (30) days prior written notice of its
intention, describing the type of New Securities, the price and the general
terms upon which the Company proposes to issue the same. Each Investor shall
have twenty (20) days from the date of mailing of any such notice to agree to
purchase its pro rata share of such New Securities for the price and upon the
general terms specified in the notice, by giving written notice to the Company
and stating therein the quantity of New Securities to be purchased.

          (c) In the event that an Investor fails to exercise in full its right
of first refusal within said twenty (20) day period, the Company shall have
seventy-five (75) days thereafter to sell (or enter into an agreement pursuant
to which the sale of New Securities covered thereby shall be closed, if at all,
within thirty (30) days from the date of said agreement) the New Securities
respecting which the Investor's rights were not exercised, at a price and upon
general terms no more favorable to the Investors thereof than specified in the
Company's notice. In the event the Company has not sold the New Securities
within said forty-five (45) day period (or sold and issued New Securities in
accordance with the foregoing within thirty (30) days from the date of said
agreement), the Company shall not thereafter issue or sell any New Securities,
without first offering such securities to the Investors in the manner provided
above.

          (d) The Investor's failure to exercise this right of first refusal on
any issuance of New Securities shall not adversely affect the Investor's right
of first refusal to purchase subsequent issuances of New Securities.

          (e) The right of first refusal set forth in this Section 3.1 is
nonassignable, except to another Investor or another entity under common control
with an Investor.

     3.2 TERMINATION. The provisions of this Section 3 shall terminate in
accordance with the provisions of Section 2.3.


                                       5.
<PAGE>


                                   SECTION 4

                               REGISTRATION RIGHTS

     4.1 REQUESTED REGISTRATION.

          (a) Request for Registration. In case the Company shall receive from
Initiating Holders a written request that the Company effect any registration,
qualification or compliance with respect to not less than forty percent (40%) of
the Registrable Securities (or a lesser percentage of the Registrable Securities
if the reasonably anticipated aggregate price to the public thereof would exceed
Five Million dollars ($5,000,000)) the Company will:

               (i) promptly give written notice of the proposed registration,
qualification or compliance to all other Holders; and

               (ii) as soon as practicable and in any event within ninety (90)
days of the receipt of such request, use its best efforts to effect such
registration, qualification or compliance (including, without limitation,
appropriate qualification under applicable blue sky or other state securities
laws and appropriate compliance with applicable regulations issued under the
Securities Act and any other governmental requirements or regulations) as may be
so requested and as would permit or facilitate the sale and distribution of all
or such portion of such Registrable Securities as are specified in such request,
together with all or such portion of the


                                       6.
<PAGE>


Registrable Securities of any Holder or Holders joining in such request as are
specified in a written request received by the Company within twenty (20) days
after receipt of such written notice from the Company.


                    PROVIDED, HOWEVER, that the Company shall not be obligated
to take any action to effect any such registration, qualification or compliance
pursuant to this Section 4.1:

                    (A) in any particular jurisdiction in which the Company
would be required to execute a general consent to service of process in
effecting such registration, qualification or compliance unless the Company is
already subject to service in such jurisdiction and except as may be required by
the Securities Act;

                    (B) prior to the earlier to occur of (i) six (6) months
after the effective date of the Company's first registered public offering of
its stock, or (ii) December 31, 2002, provided that the Company is actually
employing in good faith all reasonable efforts to cause such registration
statement to become effective;

                    (C) during the period starting with the date sixty (60) days
prior to the Company's estimated date of filing of, and ending on the date six
(6) months immediately following the effective date of, any registration
statement pertaining to securities of the Company sold by the Company (other
than a registration of securities in a Rule 145 transaction or with respect to
an employee benefit plan), provided that the Company is actively employing in
good faith all reasonable efforts to cause such registration statement to become
effective;

                    (D) after the Company has effected two (2) registrations
pursuant to this paragraph 4.1, and such registrations have been declared or
ordered effective, provided that all Registrable Securities requested to be
included in such registrations were in fact included in the registrations;
PROVIDED, HOWEVER, that the Company, upon the approval, by vote or written
consent, of the holders of at least fifty percent (50%) of the Registrable
Securities held by the Series C Holders and the Series D Holders, voting
together as a separate class, shall effect one (1) additional registration only
with respect to such Registrable Securities held by the Series C Holders and the
Series D Holders, pursuant to this Section 4.1(a)(ii); or

                    (E) if the Company shall furnish to such Holders a
certificate signed by the President of the Company stating that in the good
faith judgment of the Board of Directors it would be seriously detrimental to
the Company or its Investors for a registration statement to be filed in the
near future, then the Company's obligation to use its best efforts to register,
qualify or comply under this Section 4 shall be deferred for a period not to
exceed ninety (90) days from the date of receipt of written request from the
Initiating Holders, PROVIDED, HOWEVER, that the Company shall not utilize this
right more than once in any twelve (12) month period.

                    Subject to the foregoing clauses (A) through (E), the
Company shall file a registration statement covering the Registrable Securities
so requested to be registered as soon as practicable after receipt of the
request or requests of the Initiating Holders.



                                       7.
<PAGE>


          (b) UNDERWRITING. In the event that a registration pursuant to this
Section 4.1 is for a registered public offering involving an underwriting, the
Initiating Holders will so advise the Company as part of the written request
given by such Initiating Holders pursuant to Section 4.1(a), and the Company
shall in turn advise the Holders as part of the notice given pursuant to Section
4.1(a)(i). In such event, the right of any Holder to registration pursuant to
this Section 4.1 shall be conditioned upon such Holder's participation in the
underwriting arrangements required by this Section 4.1, and the inclusion of
such Holder's Registrable Securities in the underwriting to the extent requested
shall be limited to the extent provided herein.

          The Company shall (together with all Holders proposing to distribute
their securities through such underwriting) enter into an underwriting agreement
in customary form with the managing underwriter selected for such underwriting
by the Company, but subject to the reasonable approval of a majority in interest
of the Initiating Holders. Notwithstanding any other provision of this Section
4.1, if the managing underwriter advises the Initiating Holders in writing that
marketing factors require a limitation of the number of shares to be
underwritten, then the Company shall so advise all Holders, and the number of
shares that may be included in the registration and underwriting shall be
allocated first among all Holders in proportion, as nearly as practicable, to
the respective amounts of Registrable Securities held by such Holders at the
time of filing the registration statement; PROVIDED, HOWEVER, that no stock
other than capital stock owned by the Company is included in such registration
statement. No Registrable Securities or other securities excluded from the
underwriting by reason of the underwriter's marketing limitation shall be
included in such registration. To facilitate the allocation of shares in
accordance with the above provisions, the Company or the underwriters may round
the number of shares allocated to any holder to the nearest one hundred (100)
shares.

          If any Holder of Registrable Securities disapproves of the terms of
the underwriting, such person may elect to withdraw therefrom by written notice
to the Company, the managing underwriter and the Initiating Holders. The
Registrable Securities and/or other securities so withdrawn shall also be
withdrawn from registration.

     4.2 COMPANY REGISTRATION.

          (a) NOTICE OF REGISTRATION. If at any time, or from time to time, the
Company shall determine to register any of its securities, either for its own
account or the account of a security holder or holders, other than (i) a
registration relating solely to employee benefit plans, or (ii) a registration
relating solely to a Commission Rule 145 transaction, the Company will:

               (i) promptly give to each Holder written notice thereof; and

               (ii) include in such registration (and any related qualification
under blue sky laws or other compliance), and in any underwriting involved
therein, all the Registrable Securities specified in a written request or
requests made, within twenty (20) days after receipt of such written notice from
the Company, by any Holder.

          (b) UNDERWRITING. If the registration of which the Company gives
notice is for a registered public offering involving an underwriting, the
Company shall so advise the Holders as a part of the written notice given
pursuant to Section 4.2(a)(i). In such event the right



                                       8.
<PAGE>

of any Holder to registration pursuant to this Section 4.2 shall be conditioned
upon such Holder's participation in such underwriting and the inclusion of
Registrable Securities in the underwriting to the extent provided herein. All
Holders proposing to distribute their securities through such underwriting
shall, together with the Company, enter into an underwriting agreement in
customary form with the managing underwriter selected for such underwriting by
the Company. Notwithstanding any other provision of this Section 4.2, if the
managing underwriter determines that marketing factors require a limitation of
the number of shares to be underwritten, the managing underwriter may limit the
number of shares of Registrable Securities to be included in such registration
without requiring any limitation in the number of shares to be registered on
behalf of the Company, provided that if such underwriting is other than an
initial public offering, (i) the number of shares of Registrable Securities to
be included in such registration shall not be limited to less than thirty
percent (30%) of the total number of shares to be included in such registration,
and (ii) no shares owned by a person or entity who is not a party to this
Agreement, or entitled to the benefits hereof pursuant to Section 4.10, shall be
included in such registration. The Company shall so advise all Holders and the
number of shares that may be included in the registration and underwriting by
all Holders shall be allocated among the Holders of Registrable Securities in
proportion to the respective amounts of Registrable Securities held by such
Holders at the time of filing of the registration statement. To facilitate the
allocation of shares in accordance with the above provisions, the Company may
round the number of shares allocated to any Holder to the nearest one hundred
(100) shares. If any Holder disapproves of the terms of any such underwriting,
such holder may elect to withdraw therefrom by written notice to the Company and
the managing underwriter. Any securities excluded or withdrawn from such
underwriting shall be withdrawn from such registration.

          (c) RIGHT TO TERMINATE REGISTRATION. The Company shall have the right
to terminate or withdraw any registration initiated by it under this Section 4.2
prior to the effectiveness of such registration whether or not any Holder has
elected to include Registrable Securities in such registration.

     4.3 REGISTRATION ON FORM S-3.

          (a) REQUEST FOR REGISTRATION. If any Holder or Holders request that
the Company file a registration statement on Form S-3 (or any successor form to
Form S-3) for a public offering of shares of the Registrable Securities the
reasonably anticipated aggregate price to the public of which would exceed Three
Million dollars ($3,000,000), and the Company is a registrant entitled to use
Form S-3 to register the Registrable Securities for such an offering, the
Company shall use its best efforts to cause such Registrable Securities to be
registered for the offering on such form and to cause such Registrable
Securities to be qualified in such jurisdictions as the Holder or Holders may
reasonably request. The substantive provisions of Section 4.1(a)(i) and (ii)
(not including the proviso immediately following paragraph (ii) and of Section
4.1(b) shall be applicable to each registration initiated under this Section
4.3.

          (b) LIMITATIONS. Notwithstanding the foregoing, the Company shall not
be obligated to take any action pursuant to this Section 4.3: (i) in any
particular jurisdiction in which the Company would be required to execute a
general consent to service of process in effecting such registration,
qualification or compliance unless the Company is already subject to service in
such jurisdiction and except as may be required by the Securities Act; (ii)
during the



                                       9.
<PAGE>

period starting with the date sixty (60) days prior to the Company's estimated
date of filing of, and ending on the date six (6) months immediately following,
the effective date of any registration statement pertaining to securities of the
Company (other than a registration of securities in a Rule 145 transaction or
with respect to an employee benefit plan), provided that the Company is actively
employing in good faith all reasonable efforts to cause such registration
statement to become effective; or (iii) if the Company shall furnish to such
Holder a certificate signed by the President of the Company stating that in the
good faith judgment of the Board of Directors it would be seriously detrimental
to the Company or the Investors as a whole for registration statements to be
filed in the near future, then the Company's obligation to use its best efforts
to file a registration statement shall be deferred for a period not to exceed
ninety (90) days from the receipt of the request to file such registration by
such Holder, PROVIDED, HOWEVER, that the Company shall not utilize this right
more than once in any twelve (12) month period.

     4.4 LIMITATIONS ON SUBSEQUENT REGISTRATION RIGHTS. From and after the date
hereof, the Company will not, without the prior written consent of the holders
of a majority of the voting power of the then outstanding Registrable
Securities, enter into any agreement with any holder or prospective holder of
any securities of the Company which allows such holder or prospective holder of
any securities of the Company to include such securities in any registration
filed under Sections 4.1, 4.2 or 4.3 hereof, unless, under the terms of such
agreement, such holder or prospective holder may include such securities in any
such registration only to the extent that the inclusion of such securities will
not diminish the amount of Registrable Securities which are included. However,
the Company may by agreement grant such holder or prospective holder a
registration right analogous to that set forth in Section 4.1 provided that (i)
such holder or prospective holder may not demand a registration analogous to
that set forth in Section 4.1 at any time earlier than the Holders first have
such right or within one hundred twenty (120) days of the effective date of any
registration effected pursuant to Section 4.1, and (ii) that the Registrable
Securities may be included in any such registration demanded by such holders to
the extent such inclusion will not diminish the amount of securities of such
holders which are included.

     4.5 EXPENSES OF REGISTRATION.

          (a) REGISTRATION EXPENSES. The Company shall bear all Registration
Expenses incurred in connection with all registrations pursuant to Section 4.1,
Section 4.2 and Section 4.3 hereof, including the expense of one special counsel
to the selling Holders, not to exceed Twenty-Five Thousand dollars ($25,000).

          (b) SELLING EXPENSES. All Selling Expenses relating to securities
registered on behalf of the Holders shall be borne by the Holders pro rata on
the basis of the number of shares so registered.

     4.6 REGISTRATION PROCEDURES. In the case of each registration,
qualification or compliance effected by the Company pursuant to this Agreement,
the Company will:

          (a) keep each Holder advised in writing as to the initiation of each
registration, qualification and compliance and as to the completion thereof;



                                      10.
<PAGE>

         (b) as soon as practicable, prepare and file with the Commission a
registration statement with respect to such securities and use its best efforts
to cause such registration statement to become and remain effective until the
earlier of (i) one hundred twenty (120) days, or (ii) the distribution described
in the Registration Statement has been completed; PROVIDED, HOWEVER, that (i)
such one hundred twenty (120) day period shall be extended for a period of time
equal to the period the Holder refrains from selling any securities included in
such registration at the request of an underwriter of Common Stock (or other
securities) of the Company, and (ii) in the case of any registration of
Registrable Securities on Form S-3 which are intended to be offered on a
continuous or delayed basis, such one hundred twenty (120) day period shall be
extended, if necessary, to keep the registration statement effective until all
such Registrable Securities are sold, provided that Rule 415, or any successor
rule under the Securities Act, permits an offering on a continuous or delayed
basis, and, provided further, that applicable rules under the Securities Act
governing the obligation to file a post-effective amendment permit, in lieu of
filing a post-effective amendment, which (I) includes any prospectus required by
Section 10(a)(3) of the Securities Act, or (II) reflects facts or events
representing a material or fundamental change in the information set forth in
the registration statement, the incorporation by reference of information
required to be included in (I) and (II) above to be contained in periodic
reports filed pursuant to Section 13 or 15(d) of the Exchange Act in the
registration statement;

         (c) furnish to the Holders participating in such registration and to
the underwriters of the securities being registered such reasonable number of
copies of the registration statement, preliminary prospectus, final prospectus
and such other documents as such underwriters may reasonably request in order to
facilitate the public offering of such securities;

         (d) prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in connection
with such registration statement as may be necessary to comply with the
provisions of the Securities Act with respect to the disposition of all
securities covered by such registration statement;

         (e) in the event of an underwritten public offering, enter into and
perform its obligations under an underwriting agreement, in usual and customary
form, with the managing underwriter of such offering. Each Holder participating
in such underwriting shall also enter into and perform its obligations under
such an agreement;

         (f) notify each Holder of Registrable Securities covered by such
registration statement at any time when a prospectus relating thereto is
required to be delivered under the Securities Act of the happening of any event
as a result of which the prospectus included in such registration statement, as
then in effect, includes an untrue statement of material fact or omits to state
a material fact required to be stated therein or necessary to make the
statements made therein not misleading in the light of the circumstances then
existing; and

         (g) provide a transfer agent and registrar for all Registrable
Securities registered pursuant hereunder and a CUSIP number for all such
Registrable Securities, in each case not later than the effective date of such
registration.


                                       11
<PAGE>




     4.7 INDEMNIFICATION.

         (a) BY COMPANY. The Company will indemnify each Holder, each of its
officers and directors and partners and each person controlling such Holder
within the meaning of Section 15 of the Securities Act, with respect to which
registration, qualification or compliance has been effected pursuant to this
Agreement, each underwriter, if any, and each person who controls any
underwriter within the meaning of Section 15 of the Securities Act and each
Investor and its officers, directors and partners and each person controlling
such Investor within the meaning of Section 15 of the Securities Act, against
all expenses, claims, losses, damages or liabilities, joint or several, (or
actions in respect thereof), including any of the foregoing incurred in
settlement of any litigation, commenced or threatened, arising out of or based
on any untrue statement (or alleged untrue statement) of a material fact
contained in any registration statement, prospectus, offering circular or other
document, or any amendment or supplement thereto, incident to any such
registration, qualification or compliance or based on any omission (or alleged
omission) to state therein a material fact required to be stated therein or
necessary to make the statements therein, in light of the circumstances in which
they were made, not misleading or any violation by the Company of the Securities
Act, the Exchange Act or any state or federal securities law, or any rule or
regulation promulgated under such Acts or law applicable to the Company in
connection with any such registration, qualification or compliance, and the
Company will reimburse each such Holder, each of its officers, directors and
partners, and each person controlling such Holder, each such underwriter and
each person who controls any such underwriter, each Investor, each of its
officers, directors and partners and each person controlling such Investor, for
any legal and any other expenses reasonably incurred in connection with
investigating, preparing or defending any such claim, loss, damage, liability or
action, provided that the Company will not be liable in any such case to the
extent that any such claim, loss, damage, liability or expense arises out of or
is based on any untrue statement or omission or alleged untrue statement or
omission, made in reliance upon and in conformity with written information
furnished to the Company by an instrument duly executed by such Holder,
controlling person, underwriter or Investor and stated to be specifically for
use therein. If the Holders and Investors are represented by counsel other than
counsel for the Company, the Company will not be obligated under this Section
4.7(a) to reimburse legal fees and expenses of more than one separate counsel
for all Holders and Investors.

         (b) BY HOLDERS. Each Holder will, if Registrable Securities held by
such Holder are included in the securities as to which such registration,
qualification or compliance is being effected, indemnify the Company, each of
its directors, each of its officers, each underwriter, if any, of the Company's
securities covered by such a registration statement, each person who controls
the Company or such underwriter within the meaning of Section 15 of the
Securities Act, and each other such Holder, each of its officers and directors
and each person controlling such Holder within the meaning of Section 15 of the
Securities Act, against all claims, losses, damages and liabilities (or actions
in respect thereof) arising out of or based on any untrue statement (or alleged
untrue statement) of a material fact contained in any such registration
statement, prospectus, offering circular or other document, or any omission (or
alleged omission) to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, and will reimburse
the Company, such Holders, such directors, officers, persons, underwriters or
control persons for any legal or any other expenses reasonably incurred in
connection with investigating or defending any such claim, loss, damage,


                                       12
<PAGE>


liability or action, in each case to the extent, but only to the extent, that
such untrue statement (or alleged untrue statement) or omission (or alleged
omission) is made in such registration statement, prospectus, offering circular
or other document in reliance upon and in conformity with written information
furnished to the Company by an instrument duly executed by such Holder and
stated to be specifically for use therein. Notwithstanding the foregoing, the
liability of each Holder under this subsection (b) shall be limited in an amount
equal to the public offering price of the shares sold by such Holder, unless
such liability arises out of or is based on willful misconduct by such Holder.

         (c) PROCEDURES. Each party entitled to indemnification under this
Section 4.7 (the "INDEMNIFIED PARTY") shall give notice to the party required to
provide indemnification (the "INDEMNIFYING PARTY") promptly after such
Indemnified Party has actual knowledge of any claim as to which indemnity may be
sought, and shall permit the Indemnifying Party to assume the defense of any
such claim or any litigation resulting therefrom, provided that counsel for the
Indemnifying Party, who shall conduct the defense of such claim or litigation,
shall be approved by the Indemnified Party (whose approval shall not
unreasonably be withheld), and the Indemnified Party may participate in such
defense at such party's expense, and provided further that the failure of any
Indemnified Party to give notice as provided herein shall not relieve the
Indemnifying Party of its obligations under this Agreement unless the failure to
give such notice is materially prejudicial to an Indemnifying Party's ability to
defend such action and provided further, that the Indemnifying Party shall not
assume the defense for matters as to which there is a conflict of interest or
separate and different defenses. No Indemnifying Party, in the defense of any
such claim or litigation, shall, except with the consent of each Indemnified
Party, consent to entry of any judgment or enter into any settlement which does
not include as an unconditional term thereof the giving by the claimant or
plaintiff to such Indemnified Party of a release from all liability in respect
to such claim or litigation.

         (d) CONTRIBUTION. If the indemnification provided for in this Section
4.7 is held by a court of competent jurisdiction to be unavailable to an
Indemnified Party with respect to any loss, liability, claim, damage or expense
referred to therein, then the indemnifying party, in lieu of indemnifying such
indemnified party hereunder, shall contribute to the amount paid or payable by
such indemnified party as a result of such loss, liability, claim, damage or
expense in such proportion as is appropriate to reflect the relative fault of
the indemnifying party on the one hand and of the indemnified party on the other
in connection with the statements or omissions that resulted in such loss,
liability, claim, damage or expense as well as any other relevant equitable
considerations. The relative fault of the indemnifying party and of the
indemnified party shall be determined by reference to, among other things,
whether the untrue or alleged untrue statement of a material fact or the
omission to state a material fact relates to information supplied by the
indemnifying party or by the indemnified party and the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
statement or omission.

         (e) CONTROLLING AGREEMENT. Notwithstanding the foregoing, to the extent
that the provisions on indemnification and contribution contained in the
underwriting agreement entered into in connection with the underwritten public
offering are in conflict with the foregoing provisions of this Section 4.7, the
provisions in the underwriting agreement shall control.



                                       13
<PAGE>



     4.8 INFORMATION BY HOLDER. The Holder or Holders of Registrable Securities
included in any registration shall furnish to the Company such information
regarding such Holder or Holders, the Registrable Securities held by them and
the distribution proposed by them as the Company may request in writing and only
as shall be necessary to enable the Company to comply with the provisions hereof
in connection with any registration, qualification or compliance referred to in
this Agreement.

     4.9 RULE 144 REPORTING. With a view to making available the benefits of
certain rules and regulations of the Commission which may at any time permit the
sale of the Registrable Securities to the public without registration, after
such time as a public market exists for the Common Stock, the Company agrees to
use its best efforts to:

         (a) Make and keep public information available, as those terms are
understood and defined in Rule 144 under the Securities Act, at all times after
the effective date that the Company becomes subject to the reporting
requirements of the Securities Act or the Exchange Act;

         (b) Use its best efforts to file with the Commission in a timely manner
all reports and other documents required of the Company under the Securities Act
and the Exchange Act (at any time after it has become subject to such reporting
requirements);

         (c) Furnish to any Holder forthwith upon request a written statement by
the Company as to its compliance with the reporting requirements of Rule 144 (at
any time after ninety (90) days from the effective date of the first
registration statement filed by the Company for an offering of its securities to
the general public), and of the Securities Act and the Exchange Act (at any time
after it has become subject to such reporting requirements), a copy of the most
recent annual or quarterly report of the Company, and such other reports and
documents of the Company and other information in the possession of or
reasonably obtainable by the Company as such Holder may reasonably request in
availing itself of any rule or regulation of the Commission allowing such Holder
to sell any such securities without registration.

     4.10 TRANSFER OF REGISTRATION RIGHTS. The rights to cause the Company to
register securities granted Holders under Sections 4.1, 4.2 and 4.3 may be
assigned in connection with any transfer or assignment by a Holder of
Registrable Securities provided that: (i) such transfer may otherwise be
effected in accordance with applicable securities laws, (ii) such transfer is
effected in compliance with the restrictions on transfer contained in this
Agreement and in any other agreement between the Company and the Holder, and
(iii) such assignee or transferee is a constituent partner of an Investor or
purchases (i) at least fifty thousand (50,000) shares of Preferred or (ii) all
shares of Preferred held by an Investor if transferred to a single entity;
PROVIDED, HOWEVER, the transferee shall agree in writing to be bound by the
terms of this Agreement. No transfer or assignment will divest a Holder or any
subsequent owner of such rights and powers unless all Registrable Shares are
transferred or assigned.

     4.11 TERMINATION. The rights granted pursuant to this Section 4 shall
terminate as to each Holder following the effective date of the Company's


                                       14
<PAGE>


first registered public offering of its stock and at such time such Holder may
sell under Rule 144, or a successor rule, in a three-month period all
Registrable Securities then held by such Holder, regardless of whether such
Holder is an affiliate of the Company.

     4.12 LOCKUP AGREEMENT. Each Holder agrees that, if, in connection with the
Company's initial public offering of the Company's securities, the Company or
the underwriters managing the offering so request, the Holder shall not sell,
make any short sale of, loan, grant any option for the purchase of or otherwise
dispose of any Registrable Securities (other than those included in the
registration) without the prior written consent of the Company or such
underwriters, as the case may be, for such period of time (not to exceed one
hundred eighty (180) days) from the effective date of such registration as may
be requested by the Company or the underwriters; provided that each officer and
director of the Company who owns stock of the Company also agrees to such
restrictions. This Section 4.12 shall be binding on all transferees or assignees
of Registrable Securities, whether or not such persons are entitled to
registration rights pursuant to Section 4.10.



                                       15
<PAGE>



                                    SECTION 5

                                     LEGENDS

     5.1 LEGENDS. Each Investor understands that the share certificates
evidencing any Registrable Securities shall be endorsed with the following
legends (in addition to any legends required under applicable state securities
laws):

         (a) "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR
INVESTMENT AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR
DISTRIBUTION THEREOF. NO SUCH SALE OR DISPOSITION MAY BE EFFECTED WITHOUT AN
EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL
SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED."

         (b) "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A LOCKUP
NOT TO EXCEED 180 DAYS FOLLOWING THE COMPANY'S INITIAL PUBLIC OFFERING, A  COPY
OF WHICH LOCKUP IS ON FILE AT THE PRINCIPAL OFFICE OF THE COMPANY."

         (c) Any legend required to be placed thereon by the California
Commissioner of Corporations or any other applicable state securities laws.



                                       16
<PAGE>



                                   SECTION 6

                                  MISCELLANEOUS

     6.1 GOVERNING LAW. This Agreement shall be governed in all respects by the
laws of the State of Delaware, as such laws are applied to agreements between
Delaware residents entered into and performed entirely in Delaware.

     6.2 ENTIRE AGREEMENT; AMENDMENT. This Agreement constitutes the full and
entire understanding and agreement between the parties with regard to the
subjects hereof and thereof. This Agreement or any term hereof may be amended,
waived, discharged or terminated by a written instrument signed by the Company
and the Holders or transferees of such Holders holding more than fifty percent
(50%) of the Registrable Securities.

     6.3 AGGREGATION. For the purposes of determining the number of shares of
Registrable Securities held by an Investor, Holder, transferee or assignee, the
holdings of affiliates shall be aggregated together and with the holdings of
such Investor, Holder, transferee or assignee, respectively; provided, that all
assignees and transferees who would not qualify individually for assignment of
registration rights shall have a single attorney-in-fact for the purpose of
exercising any rights, receiving notices or taking any action under Sections 2
and 4.

     6.4 NOTICES, ETC. All notices and other communications required or
permitted hereunder shall be deemed given if in writing and mailed by registered
or certified mail, postage prepaid, or otherwise delivered by hand or by
messenger, addressed (a) if to a Holder, at such Holder's address as set forth
on Exhibit A to this Agreement, or at such other address as such Holder shall
have furnished to the Company in writing, or (b) if to any other holder of any
Registrable Securities, at such address as such holder shall have furnished the
Company in writing, or, until any such holder so furnishes an address to the
Company, then to and at the address of the last holder of such Registrable
Securities who has so furnished an address to the Company, or (c) if to the
Company, at the address of its principal offices and addressed to the attention
of the Corporate Secretary and with a copy to Cooley Godward LLP, 3000 El Camino
Real, 5 Palo Alto Square, Palo Alto, California 94306, Attention: Robert L.
Jones, or at such other address as the Company shall have furnished to the
Investors.

     6.5 ADDITIONAL PURCHASERS. Notwithstanding anything to the contrary
contained herein, if the Company shall issue additional shares of its Preferred
Stock, any purchaser of such shares of Preferred Stock may become a party to
this Agreement by executing and delivering an additional counterpart signature
page to this Agreement and shall be deemed an "Investor" hereunder.

     6.6 SEVERABILITY. In the event that any provision of this Agreement becomes
or is declared by a court of competent jurisdiction to be illegal, unenforceable
or void, this Agreement shall continue in full force and effect without said
provision; provided that no such severability shall be effective if it
materially changes the economic benefit of this Agreement to any party.

     6.7 COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be enforceable against the parties actually
executing such counterparts, and all of which together shall constitute one
instrument.



                                       17
<PAGE>



The foregoing Agreement is hereby executed as of the date first above written.


THE "COMPANY"                         DNA SCIENCES, INC.
                                      a Delaware corporation


                                      By:
                                         ---------------------------
                                         Hugh Y. Rienhoff, Jr.
                                         Chairman & CEO




<PAGE>


"INVESTORS"                           AMERSHAM PHARMACIA BIOTECH, INC.


                                      By:
                                         ---------------------------

                                      Its:
                                         ---------------------------




<PAGE>




"INVESTORS"

                                       APPLE TREE PARTNERS I L.P.



                                      By:
                                         ---------------------------

                                      Its:
                                         ---------------------------




<PAGE>




"INVESTORS"

                                      BRENTWOOD ASSOCIATES VIII, L.P.

                                      By: Brentwood VIII Ventures, L.L.C.

                                      Its:  General Partner



                                      By:
                                         ---------------------------

                                      Its:
                                         ---------------------------




                                      BRENTWOOD AFFILIATES FUND II, L.P.

                                      By: Brentwood VIII Ventures, L.L.C.

                                      Its:  General Partner



                                      By:
                                         ---------------------------

                                      Its:
                                         ---------------------------



<PAGE>

"INVESTORS"


                                  -------------------------------------------
                                  WILLIAM R.  BRODY

<PAGE>

"INVESTORS"


                                  -------------------------------------------
                                  ROBERT J. CARPENTER

<PAGE>

"INVESTORS"


                                  CLSP, L.P.



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------



                                  CLSP-SBS I, L.P.


                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------



                                  CLSP-SBS II, L.P.



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------



                                  CLSP II, L.P.


                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

                                  CLSP OVERSEAS, LTD.



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  COOLEY GODWARD LLP



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  DOMAIN PARTNERS IV, L.P.



                                  By:
                                      ---------------------------------------
                                          Managing Member


                                  DP IV ASSOCIATES, L.P.

                                  By: One Palmer Square Associates IV, L.L.C.
                                      Its General Partner


                                  By:
                                     ----------------------------------------
                                       Managing Member

<PAGE>

"INVESTORS"



                                  -------------------------------------------
                                  JAY T. FLATLEY

<PAGE>

"INVESTORS"



                                  GC&H INVESTMENTS


                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  WEB MD CORPORATION


                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  -------------------------------------------
                                  RICHARD A. MATHIES

<PAGE>

"INVESTORS"



                                  MONACO PARTNERS, L.P.
                                  By: Clark Ventures, Inc.
                                      Its General Partner


                                  By:
                                      ---------------------------------------

                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  ORACLE CORPORATION



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  PEQUOT HEALTHCARE FUND, L.P.
                                  BY: PEQUOT CAPITAL MANAGEMENT, INC.
                                  AS INVESTMENT MANAGER



                                  By:
                                      ---------------------------------------
                                      David J. Malat


                                  Its:
                                      ---------------------------------------



                                  PEQUOT HEALTHCARE OFFSHORE FUND, INC.
                                  BY: PEQUOT CAPITAL MANAGEMENT, INC.,
                                  AS INVESTMENT ADVISOR



                                  By:
                                      ---------------------------------------
                                      David J. Malat


                                  Its:
                                      ---------------------------------------



                                  PEQUOT HEALTHCARE INSTITUTIONAL FUND, L.P.
                                  BY: PEQUOT CAPITAL MANAGEMENT, INC.,
                                  AS INVESTMENT ADVISOR



                                  By:
                                      ---------------------------------------
                                      David J. Malat


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  PHARMACEUTICAL PRODUCT DEVELOPMENT, INC.



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  AXYS PHARMACEUTICALS, INC.



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  QUANTUM PARTNERS LDC



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------



                                  QUANTUM INDUSTRIAL PARTNERS LDC



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------



                                  SFM DOMESTIC INVESTMENTS LLC



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  RUSSELL RANDOLPH & CYNTHIA Y. SCOTT OR
                                  THEIR SUCCESSORS IN TRUST U/T/D JUNE 22, 1998,
                                  AS MAY BE AMENDED
                                  312 COLERIDGE AVENUE
                                  PALO ALTO, CA  94301



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  -------------------------------------------
                                  FRANCIS COLSTON RIENHOFF

<PAGE>

"INVESTORS"



                                  -------------------------------------------
                                  HUGH Y. RIENHOFF, AN INDIVIDUAL

<PAGE>

"INVESTORS"



                                  JAMES M. SCHLATER AND MARILYN L. SCHLATER
                                  TRUST DATED 4/9/90



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                  -------------------------------------------
                                  GREGORY T. WENT, AN INDIVIDUAL

<PAGE>

"INVESTORS"



                                  -------------------------------------------
                                  STEVEN B. LEHRER, AN INDIVIDUAL

<PAGE>

"INVESTORS"



                                  DEUTSCHE
                                  VERMOEGENSBILDUNGSGESELLSCHAFT



                                  By:
                                      ---------------------------------------


                                  Its:
                                      ---------------------------------------

<PAGE>

"INVESTORS"



                                     DEUTSCHE ASSET MANAGEMENT (NAVAP)



                                     By:
                                        --------------------------------------


                                     Its:
                                          ------------------------------------


<PAGE>

"INVESTORS"



                                     TALLWOOD I, L.P.



                                     By:
                                        --------------------------------------


                                     Its:
                                         -------------------------------------


<PAGE>

"INVESTORS"



                                     SPARKS PARTNERS, L.P.



                                     By:
                                        --------------------------------------


                                     Its:
                                         -------------------------------------


<PAGE>

"INVESTORS"



                                     THE UNIVERSITY OF UTAH RESEARCH FOUNDATION



                                     By:
                                        --------------------------------------


                                     Its:
                                         -------------------------------------

<PAGE>

"INVESTORS"



                                     HOGAN & HARTSON L.L.P.



                                     By:
                                        --------------------------------------


                                     Its:
                                         -------------------------------------


<PAGE>

"INVESTORS"



                                     -----------------------------------------
                                     HUGH WILLBOURN

<PAGE>

                                   EXHIBIT A

                             SCHEDULE OF INVESTORS

Name and Address of Investor


Pharmaceutical Product Development, Inc.
3151 17th Street Extension
Wilmington, NC 28412

Amersham Pharmacia Biotech, Inc.
800 Centennial Avenue 30
PO Box 1327
Piscataway, NJ  0885-1327

Apple Tree Partners I, L.P.
The Chrysler Building
405 Lexington Avenue, 45th Floor
New York, NY 10174
Attn: Seth Harrison

Atherton Properties Partnership, L.P.
2025 Garcia Avenue
Mountain View, CA 94043

Axys Pharmaceuticals, Inc.
180 Kimball Way
South San Francisco, CA 94080
Attention: William J. Newell

Brentwood Affiliates Fund II, L.P.
3000 Sand Hill Road, Bldg. 1
Suite 260
Menlo Park, CA 94025
Attn:  Brian Atwood

Brentwood Associates VIII, L.P.
3000 Sand Hill Road, Bldg. 1
Suite 260
Menlo Park, CA 94025
Attn:  Brian Atwood

                                      1.

<PAGE>

CLSP II, L.P.
230 Park Avenue 20th Floor
New York, NY  10169
Attn:  Peter Freer

CLSP Overseas, Ltd
230 Park Avenue 20th Floor
New York, NY  10169
Attn: Peter Freer

CLSP, L.P.
230 Park Avenue 20th Floor
New York, NY  10169
Attn:  Peter Freer

CLSP-SBS 1, L.P.
230 Park Avenue 20th Floor
New York, NY  10169
Attn:  Peter Freer

CLSP-SBS 11, L.P.
230 Park Avenue 20th Floor
New York, NY  10169
Attn:  Peter Freer

Cooley Godward LLP
One Maritime Plaza
20th Floor
San Francisco, CA  94111-3580

Deutsche Asset Management (NAVAP)
Mainzer Landstrasse 16
60323 Frankfurt
Germany
Attn: Herr Althoff

Deutsche Vermoegensbildungsgesellschaft
Feldbergstr 23
60323 Frankfurt
Germany
Attn: Daniel Endrikat

                                      2.

<PAGE>

Domain Partners IV, L.P.
One Palmer Square
Suite 515
Princeton, NJ  08542
Attn:  Jesse Treu

DP IV Associates, L.P.
One Palmer Square
Suite 515
Princeton, NJ  08542
Attn:  Jesse Treu

Francis Colston Rienhoff
7802 Ruxwood Road
Baltimore, MD  21204

GATX Ventures, Inc.
3678 Mountain Diablo Blvd., Suite 200
Lafayette, CA 94549
Attn: Legal Department

GC&H Investments
One Maritime Plaza, 20th Floor
San Francisco, CA  94111-3580

GC&H Investments
One Maritime Plaza, 20th Floor
San Francisco, CA 94111-3580
Attn: Jim Kindler

Gregory T. Went
DNA Sciences, Inc
6540 Kaiser Drive
Fremont, CA 94555-3613

Hogan & Hartson L.L.P.
555 Thirteenth Street, N.W.
Washington, DC 20004
Attn: Raymond Calamaro

Hugh Willbourn
Corr Willbourn R&D
1 Sail Street
London SE 116NQ

                                      3.

<PAGE>

Hugh Y. Rienhoff
DNA Sciences, Inc
6540 Kaiser Drive
Fremont, CA 94555-3613

James M. Schlater and Marilyn L.
Schlater Trust Dated 4/9/90
623 Morningside
Los Altos, CA 94022

Jay T. Flatley
Illumina, Inc.
9390 Towne Centre Drive
San Diego, CA 92121

JHC Investments 2000, LLC
2025 Garcia Avenue
Mountain View, CA 94043

Monaco Partners, L.P.
777 East William Street, Suite 200
Carson City, NV 89701-4058
Attn:  Harvey Armstrong

Oracle Corporation
500 Oracle Parkway
Redwood Shores, CA  94065

Pequot Healthcare Fund, L.P.
500 Nyala Farm Road
Westport, CT. 06880
Attn: David J. Malat

Pequot Healthcare Institutional Fund, L.P.
500 Nyala Farm Road
Westport, CT. 06880
Attn: David J. Malat
Pequot Healthcare Offshore Fund, Inc.
500 Nyala Farm Road
Westport, CT. 06880
Attn: David J. Malat

                                      4.

<PAGE>

Quantum Industrial Partners LDC
888 7th Avenue, 33rd Floor
New York, NY  10106
Attn: Richard D. Holahan, Jr.

Quantum Partners LDC
888 7th Avenue, 33rd Floor
New York, NY  10106
Attn: Richard D. Holahan, Jr.

Richard Mathies
93 Danefield Place
Moraga, CA  94556

Robert J. Carpenter
9 Lowell Road
Wellesley Hills, MA  02481

Russell Randolph & Cynthia Y. Scott Or
Their Successors In Trust U/T/D June 22, 1998, As May be Amended
312 Coleridge Avenue
Palo Alto, CA  94301

SFM Domestic Investments LLC
888 7th Avenue, 33rd Floor
New York, NY  10106
Attn: Richard D. Holahan, Jr.

Sparks Partners, L.P.
4146 Roland Avenue
Baltimore, MD 21211
Attn: John Brooks

Steven B. Lehrer
DNA Sciences, Inc
6540 Kaiser Drive
Fremont, CA 94555-3613

Tallwood I, L.P.
635 Waverly Street
Palo Alto, CA 94301
Attn: Diosdado P. Banatao

                                      5.

<PAGE>

Tallwood I, L.P.
635 Waverly Street
Palo Alto, CA 94301
Attn: Diosdado P. Banatao

TBCC Funding Trust II
Transamerica Technology Finance Division
76 Batterson Park Road
Farmington, CT 06032
Attn: Legal Department

University of Utah Research Foundation
Technology Transfer Office
615 S. Arapeen Drive, Suite 110
Salt Lake City, UT 84108
Attn: Chris Jansen, PhD.
         Director

Web MD Corporation
400 Lenox Building
3399 Peachtree Road, NW
Atlanta, GA 30326

William R. Brody
Johns Hopkins University
242 Garland Hall
3400 N. Charles Street
Baltimore, MD  21218

Woodside Ventures Limited Partnership
2025 Garcia Avenue
Mountain View, CA 94043