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                                                                    EXHIBIT 10.2

                             STOCK OPTION AGREEMENT

                        (OFFICER INCENTIVE STOCK OPTION)

      THIS STOCK OPTION AGREEMENT (this "Agreement"), effective as of
______________ (the "Grant Date"), is by and between LEXICON GENETICS
INCORPORATED, a Delaware corporation (the "Company"), and ______________
("Optionee").

      To carry out the purposes of the Lexicon Genetics Incorporated 2000 Equity
Incentive Plan (the "Plan"), by providing Optionee the opportunity to purchase
shares of Common Stock, par value $0.001 per share, of the Company ("Stock"),
and in consideration of the mutual agreements and other matters set forth herein
and in the Plan, the Company and Optionee hereby agree as follows:

      1. Grant of Option. The Company hereby grants to Optionee the right and
option (the "Option") to purchase all or any part of an aggregate of ___________
shares of Stock, on the terms and conditions set forth in this Agreement and in
the Plan. The Option shall be treated as an "incentive stock option" within the
meaning of section 422(b) of the Internal Revenue Code of 1986, as amended (the
"Code"), to the maximum extent permitted under the Code, and as a non-statutory
stock option to the extent it exceeds the limitations imposed by the Code for
incentive stock options.

      2. Exercise Price. The price at which Optionee may purchase Stock upon
exercise of the Option (the "Exercise Price") shall be $_________ per share,
which has been determined to be the Fair Market Value (as defined in the Plan)
of the Stock on the Grant Date. The Exercise Price is subject to adjustment
under certain circumstances as provided in the Plan.

      3. Term. The Option shall expire on the 10th anniversary of the Grant
Date, subject to earlier termination under the circumstances specified in
Section 8 of this Agreement.

      4. Exercisability and Vesting. (a) Subject to the terms and conditions set
forth in this Agreement and the Plan, the Option may be exercised, in whole or
in part, at any time and from time to time during the term of the Option, to
purchase the number of shares of Stock that have vested and become exercisable
in accordance with this Agreement. The Option shall vest and become exercisable
with respect to (i) 25% of the total number of shares of Stock subject to the
Option on _____________ and (ii) an additional 1/48 of the total number of
shares subject to the Option each month thereafter; provided that such options
shall become vested with respect to all remaining unvested shares in the event
of a Change in Control (as defined below); and provided further, that, upon the
termination of Optionee's Continuous Service (as defined in the Plan), the
Option shall cease to vest and shall terminate with respect to all shares of
Stock that have not vested and become exercisable prior to such time.

      (b) A "Change in Control" shall be deemed to have occurred if any of the
following shall have taken place: (i) any "person" (as such term is used in
Sections 13(d) and 14(d)(2) of the Securities Exchange Act of 1934 (the
"Exchange Act")) other than Gordon Cain is or becomes the "beneficial owner" (as
defined in Rule 13d-3 under the Exchange Act, or any successor provisions
thereto), directly or indirectly, of securities of the Company representing 35%
or more of the combined voting power of the Company's then-outstanding voting
securities; (ii) the approval by the stockholders of the Company of a
reorganization, merger, or consolidation, in each case with respect to which
persons who were stockholders of the Company immediately prior to such
reorganization, merger or consolidation do not, immediately thereafter, own or
control more than 50% of the combined voting power of the reorganized, merged or
consolidated Company's then-outstanding
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securities entitled to vote generally in the election of directors in
substantially the same proportions as their ownership of the Company's
outstanding voting securities prior to such reorganization, merger or
consolidation; (iii) a liquidation or dissolution of the Company or the sale of
all or substantially all of the Company's assets; (iv) in the event any person
is elected by the stockholders of the Company to the Company's board of
directors (the "Board") who has not been nominated for election by a majority of
the Board or any duly appointed committee thereof; or (v) following the election
or removal of directors, a majority of the Board consists of individuals who
were not members of the Board two years before such election or removal, unless
the election of each director who is not a director at the beginning of such
two-year period has been approved in advance by directors representing at least
a majority of the directors then in office who were directors at the beginning
of the two-year period. The Compensation Committee of the Board, in its
discretion, may deem any other corporate event affecting the Company to be a
"Change in Control" hereunder.

      5. Procedures for Exercise. Subject to the terms and conditions set forth
in this Agreement and the Plan, the Option may be exercised by delivery to the
Company at its principal executive office of (i) written notice addressed to the
Secretary of the Company specifying the number of shares of Stock as to which
the Option is being exercised and (ii) payment in full of the Exercise Price for
such shares. The Exercise Price shall be paid in cash or in such other manner as
may be authorized by the administrator of the Plan in accordance with the terms
of the Plan. If the offering, sale and delivery of the shares of Stock issuable
upon exercise of the Option have not been registered under the Securities Act of
1933 (the "Securities Act"), the Company may require Optionee, as a condition to
Optionee's exercise of the Option, to enter into a stock purchase agreement
containing such representations and warranties as the Company may deem necessary
to permit the issuance of the Stock purchased upon exercise of the Option in
compliance with the Securities Act and applicable state securities laws.

      6. No Rights of Ownership in Stock Before Issuance. No person shall be
entitled to the rights and privileges of stock ownership with respect to any
shares of Stock issuable upon exercise of the Option until such shares have been
issued in accordance with the terms of this Agreement and the Plan.

      7. Non-Transferability. The Option may not be transferred by Optionee
otherwise than by will or the laws of descent and distribution or pursuant to a
qualified domestic relations order (as defined in Title I of the Employee
Retirement Income Security Act of 1974, as amended, or the rules thereunder).

      8. Termination of Option. If Optionee's Continuous Service is terminated
for any reason other than (i) the Disability (as defined in the Plan) or death
of Optionee or (ii) the Company's termination of Optionee's employment without
cause, the Option shall remain exercisable, with respect to the shares of Stock
that had vested under the terms of this Agreement before the date of such
termination, for a period of 90 days after the date of such termination (but in
no event later than the expiration date of the Option specified in Section 3 of
this Agreement), following which 90-day period this Agreement and Optionee's
right to exercise the Option shall terminate. If Optionee's Continuous Service
is terminated because of (i) the Disability or death of Optionee or (ii) the
Company's termination of Optionee's employment without cause, the Option shall
remain exercisable, with respect to the shares of Stock that had vested under
the terms of this Agreement before the date of such termination, for a period of
one year after the date of such termination (but in no event later than the
expiration date of the Option specified in Section 3 of this Agreement),
following which one-year period this Agreement and Optionee's right to exercise
the Option shall terminate; provided that the Option shall not be treated as an
"incentive stock option" within the meaning of the Code if the Option is
exercised more than 90 days following the termination of Optionee's Continuous
Service as a result of the Company's termination of Optionee's employment
without cause. Notwithstanding the foregoing, if the employment of Optionee by
the Company is terminated for cause, this Agreement and Optionee's right to
exercise any portion of the Option, whether or not vested, shall terminate at
the commencement of business on the date of such termination. For purposes of
this Agreement, "cause" shall mean (x) the breach of a material obligation of

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Optionee under any agreement between Optionee and the Company, (y) gross
negligence or willful or intentional wrongdoing or misconduct on the part of
Optionee, or (z) Optionee's conviction of a felony offense or a crime involving
moral turpitude.

      9. Withholding of Tax. To the extent that the Company is required under
applicable federal or state income tax laws to withhold any amount on account of
any present or future tax imposed as a result of the exercise of the Option,
Optionee shall pay the Company, at the time of such exercise, funds in an amount
sufficient to permit the Company to satisfy such withholding obligations in
full. If Optionee fails to pay such amount, the Company shall be authorized (i)
to withhold from any cash remuneration then or thereafter payable to Optionee
any tax required to be withheld or (ii) to refuse to issue or transfer any
shares otherwise required to be issued pursuant to the terms of this Agreement.

      10. Status of Stock. (a) Unless the offering, sale and delivery of the
shares of Stock issuable upon exercise of the Option have been registered under
the Securities Act, Optionee agrees that any shares of Stock purchased upon
exercise of the Option shall be acquired for investment without a view to
distribution, within the meaning of the Securities Act, and shall not be sold,
transferred, assigned, pledged or hypothecated in the absence of an effective
registration statement under the Securities Act and applicable state securities
laws or an applicable exemption from the registration requirements of the Act
and any applicable state securities laws. Optionee further agrees that the
shares of Stock which Optionee may acquire by exercising the Option will not be
sold or disposed of in any manner which would constitute a violation of any
other applicable federal or state securities laws. In addition, Optionee agrees
(i) that the certificates representing the shares of Stock issued under this
Agreement may bear such legend or legends as the administrator of the Plan deems
appropriate in order to assure compliance with applicable securities laws, and
(ii) that the Company may give instruction to its transfer agent, if any, to
stop transfer of the shares of Stock issued under this Agreement on the stock
transfer records of the Company, if such proposed transfer would, in the opinion
of counsel to the Company, constitute a violation of any applicable securities
law or any such agreements.

      (b) Optionee further agrees that the Option granted herein shall be
subject to the requirement that if at any time the administrator of the Plan
shall determine, in its discretion, that the listing, registration or
qualification of the shares of Stock subject to such Option upon any securities
exchange or market or under any state or federal law, or the consent or approval
of any governmental regulatory body, is necessary or desirable as a condition
of, or in connection with, the purchase or issuance of shares of Stock
hereunder, such Option may not be exercised in whole or in part unless such
listing, registration, qualification, consent or approval shall have been
effected or obtained free of any conditions not reasonably acceptable to the
administrator of the Plan.

      11. Stock Option Plan. The Plan, a copy of which is available for
inspection by Optionee or other persons entitled to exercise this Option at the
Company's principal executive office during business hours, is incorporated by
reference in this Agreement. The Option is subject to, and the Company and
Optionee agree to be bound by, all of the terms and conditions of the Plan. In
the event of a conflict between this Agreement and the Plan, the terms of the
Plan shall control. Subject to the terms of the Plan, the administrator of the
Plan shall have authority to construe the terms of this Agreement, and the
determinations of the administrator of the Plan shall be final and binding on
Optionee and the Company.

      12. Binding Agreement. This Agreement shall be binding upon and inure to
the benefit of any successors to the Company and all persons lawfully claiming
under Optionee.

      13. Governing Law. This Agreement and all actions taken hereunder shall be
governed by and construed in accordance with the laws of the State of Delaware.

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      IN WITNESS WHEREOF, the Company has caused this Agreement to be duly
executed and Optionee has executed this Agreement as of the day and year first
above written.

                                     LEXICON GENETICS INCORPORATED

                                     By: _______________________________________
                                           Arthur T. Sands, M.D., Ph.D.
                                           President and Chief Executive Officer

                                     OPTIONEE

                                     ___________________________________________

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