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                                                                     EXHIBIT 4.9

                                    WARRANT

THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS, AND HAS 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,
REASONABLY SATISFACTORY TO THE COMPANY, THAT SUCH REGISTRATION IS NOT REQUIRED
UNDER THE SECURITIES ACT.

Warrant No.:EMP-101                                   Number of Shares:200,000

Date of Issuance:


                                GERON CORPORATION

                         COMMON STOCK WARRANT AGREEMENT


Geron Corporation (the "Company"), for value received, hereby certifies that Eve
M. Patton or her registered assigns (in accordance with Section 3 below) (the
"Registered Holder"), is entitled, subject to the terms set forth below, to
purchase from the Company, at any time after the date hereof and on or before
the Expiration Date (as defined in Section 6 below), up to 200,000 shares of
Common Stock of the Company, as adjusted from time to time pursuant to the terms
of this Common Stock Warrant Agreement ("Warrant"), at a purchase price of
$67.09 per share. The shares purchasable upon exercise of this Warrant are
hereinafter referred to as the "Warrant Stock." The exercise price per share of
Warrant Stock is hereinafter referred to as the "Purchase Price."

      1.    EXERCISE.

            (a)   MANNER OF EXERCISE. This Warrant may be exercised by the
Registered Holder, in whole or in part, provided that in no event shall partial
exercise be for less than 20,000 Warrant Shares, by surrendering this Warrant,
with the purchase form appended hereto as EXHIBIT A duly executed by such
Registered Holder or by such Registered Holder's duly authorized
attorney-in-fact, at the principal office of the Company, or at such other
office or agency as the Company may designate, accompanied by payment in full by
cash, check or wire transfer of the Purchase Price payable in respect of the
number of shares of Warrant Stock purchased upon such exercise.

            (b)   EFFECTIVE TIME OF EXERCISE. The exercise of this Warrant shall
be deemed to have been effected immediately prior to the close of business on
the day on which this Warrant shall have been surrendered to the Company, with
payment of the



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applicable Purchase Price, as provided in Section 1(a) above. At such time, the
person or persons in whose name or names any certificates for Warrant Stock
shall be issuable upon such exercise as provided in Section 1(c) below shall be
deemed to have become the holder or holders of record of the Warrant Stock
represented by such certificates.

            (c)   DELIVERY TO REGISTERED HOLDER. As soon as practicable after
the exercise of this Warrant, and in any event within ten (10) business days
thereafter, the Company at its expense will cause to be issued in the name of,
and delivered to, the Registered Holder, or as such Registered Holder (upon
payment by such Registered Holder of any applicable transfer taxes) may direct,
a certificate or certificates for the number of shares of Warrant Stock to which
such Registered Holder shall be entitled.

      2.    CERTAIN ADJUSTMENTS.

            (a)   MERGERS AND CONSOLIDATIONS. If at any time there shall be a
merger or consolidation of the Company with another corporation, then, as a part
of such merger or consolidation, lawful provision shall be made so that the
Registered Holder shall thereafter be entitled to receive upon exercise of this
Warrant during the period specified in this Warrant and upon payment of the
Purchase Price, the number of shares of stock or other securities or property of
the Company or the successor corporation resulting from such merger or
consolidation, to which a holder of the Common Stock deliverable upon exercise
of this Warrant would have been entitled under the provisions of the agreement
in such merger or consolidation if this Warrant had been exercised immediately
before that merger or consolidation. In any such case, appropriate adjustment
(as determined in good faith by the Company's Board of Directors) shall be made
in the application of the provisions of this Warrant with respect to the rights
and interests of the Registered Holder after the merger or consolidation to the
end that the provisions of this Warrant (including adjustment of the Purchase
Price then in effect and the number of shares of Warrant Stock) shall be
applicable after that event, as near as reasonably may be, in relation to any
shares or other property deliverable after that event upon exercise of this
Warrant.

            (b)   SPLITS, SUBDIVISIONS AND DIVIDENDS. In the event the Company
should at any time or from time to time fix a record date for the effectuation
of a split or subdivision of the outstanding shares of Common Stock or the
determination of the holders of Common Stock entitled to receive a dividend or
other distribution payable in additional shares of Common Stock or other
securities or rights convertible into, or entitling the holder thereof to
receive directly or indirectly, additional shares of Common Stock (hereinafter
referred to as the "Common Stock Equivalents") without payment of any
consideration by such holder for the additional shares of Common Stock or Common
Stock Equivalents (including the additional shares of Common Stock issuable upon
conversion or exercise thereof), then, as of such record date (or the date of
such distribution, split or subdivision if no record date is fixed), the per
share Purchase Price shall be appropriately decreased and the number of shares
of Warrant Stock shall be appropriately increased in proportion to such increase
(or potential increase) of outstanding shares.



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            (c)   COMBINATION OF SHARES. If the number of shares of Common Stock
outstanding at any time after the date hereof is decreased by a combination of
the outstanding shares of Common Stock, the per share Purchase Price shall be
appropriately increased and the number of shares of Warrant Stock shall be
appropriately decreased in proportion to such decrease in outstanding shares.

            (d)   ADJUSTMENT CERTIFICATE. When any adjustment is required to be
made in the securities issuable upon exercise of this Warrant, the Company shall
mail to the Registered Holder a certificate setting forth a statement of the
facts requiring such adjustment. Such certificate shall also set forth the kind
and amount of stock or other securities or property into which this Warrant
shall be exercisable following the occurrence of any of the events specified in
this Section 2.

      3.    TRANSFER RESTRICTIONS; REPRESENTATIONS.

            (a)   The Registered Holder acknowledges that this Warrant and the
Warrant Stock have not been registered under the Securities Act, and agrees not
to sell, pledge, distribute, offer for sale, transfer or otherwise dispose of
this Warrant or any Warrant Stock issued upon its exercise in the absence of an
opinion of counsel, reasonably satisfactory to the Company, that registration
and qualification are not required. Subject to the foregoing, the Company hereby
consents to transfer by the Registered Holder to (i) Noel Thomas Patton, (ii)
the immediate family members (i.e. parents, siblings or children, thereof) of
the Registered Holder or Noel Thomas Patton, or (iii) entities controlled by the
Registered Holder or Noel Thomas Patton or their immediate family members,
provided that the transferee certifies to the Company that it is an "accredited
investor" as defined in Rule 501 under the Securities Act and agrees to be bound
by the terms of this Warrant. It is understood and agreed that this provision
does not apply to, or limit the sale, pledge, distribution, offers for sale,
transfer or other disposition of Warrant Stock after any exercise thereof
pursuant to Section 1 hereof.

            (b)   The Registered Holder hereby further represents and warrants
to the Company with respect to the issuance of the Warrant and the purchase of
the Warrant Stock as follows:

                  (i)   PURCHASE ENTIRELY FOR OWN ACCOUNT. This Warrant is
issued to the Registered Holder in reliance upon such Registered Holder's
representation to the Company, which by such Registered Holder's execution of
this Warrant such Registered Holder hereby confirms, that the Warrant and the
Warrant Stock will be acquired for investment for such Registered Holder's own
account, not as a nominee or agent, and not with a view to the resale or
distribution of any part thereof, and that such Registered Holder has no present
intention of selling, granting any participation in, or otherwise distributing
the same.

                  (ii)  KNOWLEDGE AND EXPERIENCE; ABILITY TO BEAR ECONOMIC
RISKS. The Registered Holder has such knowledge and experience in financial and



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business matters that it is capable of evaluating the merits and risks of the
investment contemplated by this Warrant and such party is able to bear the
economic risk of its investment in the Company (including a complete loss of its
investment). The Registered Holder is and will continue to be an "accredited
investor" as defined by Rule 501 of the Securities Act.

                  (iii) RESALE. The Registered Holder understands that the
Warrant being issued hereunder and the Warrant Stock to be purchased hereunder
are characterized as "restricted securities" under the federal securities laws
inasmuch as they are being acquired from the Company in a transaction not
involving a public offering and that under such laws and applicable regulations,
such securities may be resold without registration under the Securities Act only
in certain circumstances. In this regard, the Registered Holder represents that
she is familiar with Rule 144 under the Securities Act, and understands the
resale limitations imposed thereby and by the Securities Act.

                  (iv)  LEGENDS. The Registered Holder acknowledges that all
stock certificates representing shares of stock issued to the Registered Holder
upon exercise of this Warrant may, if such Warrant Stock is not registered under
the Securities Act, have affixed thereto a legend substantially in the following
form:

                        (x)   "THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE
SECURITIES LAWS. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, HYPOTHECATED
OR OTHERWISE TRANSFERRED IN THE ABSENCE OF A REGISTRATION STATEMENT IN EFFECT
WITH RESPECT TO THE SECURITIES UNDER SUCH SECURITIES ACT OR AN OPINION OF
COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED OR
UNLESS SOLD PURSUANT TO AN EXEMPTION TO SUCH SECURITIES ACT."

                        (y)   Any legend required by the laws of any state in
which the securities will be issued.

            (c)   Subject to the provisions of Section 3(a) hereof, this Warrant
and all rights hereunder are transferable in whole or in part upon surrender of
the Warrant with a properly executed assignment (in the form of EXHIBIT B
hereto) at the principal office of the Company, provided that in no event shall
such transfer be for less than 20,000 Warrant Shares.

            (d)   The Company will maintain a register containing the names and
addresses of the Registered Holders of this Warrant. Any Registered Holder may
change such Registered Holder's address as shown on the warrant register by
written notice to the Company requesting such change.

            (f)   The Company hereby represents and warrants to the Registered
Holder as follows:



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                  (i)   The Company is a corporation validly existing and in
good standing under the laws of the State of Delaware.

                  (ii)  The Company has requisite corporate right, power and
authority (including the due authorization by all necessary corporate action) to
enter into this Warrant and to perform its obligations hereunder without the
need for the consent of any other person; and this Warrant has been duly
authorized, executed and delivered and constitutes legal, valid and binding
obligations of the Company enforceable against it in accordance with the terms
hereof. The execution, delivery and performance of this Warrant by the Company
do not contravene or violate any laws, rules or regulations applicable to it.

                  (iii) The Company has taken such corporate action as is
necessary or appropriate to enable it to perform its obligations hereunder,
including, but not limited to, the issuance, sale and delivery of the Warrant.

                  (iv)  The Warrant Stock, when issued and paid for in
compliance with the provisions of this Warrant, will be validly issued, fully
paid and non-assessable.

      4.    NO IMPAIRMENT. The Company will not, by amendment of its charter or
through reorganization, consolidation, merger, dissolution, sale of assets or
any other voluntary action, avoid or seek to avoid the observance or performance
of any of the terms of this Warrant, but will assist in the carrying out of all
such terms and in the taking of all such action as may be necessary or
appropriate in order to fulfill its obligations hereunder.

      5.    TERMINATION. This Warrant (and the right to purchase securities upon
exercise hereof) shall terminate upon the tenth anniversary of the Date of
Issuance (the "Expiration Date").

      6.    NOTICES OF CERTAIN TRANSACTIONS. In the event that:

            (a)   the Company shall take a record of the holders of its Common
Stock (or other stock or securities at the time deliverable upon the exercise of
this Warrant) for the purpose of entitling or enabling them to receive any
dividend or other distribution, or any right to subscribe for, purchase or
otherwise acquire any shares of stock of any class or any other securities or
property, or to receive any other right; or

            (b)   the Company shall effect any consolidation or merger of the
Company with or into another corporation (other than a consolidation or merger
in which the Company is the surviving entity), or any transfer of all or
substantially all of the assets of the Company, or

            (c)   the Company voluntarily or involuntarily dissolves, liquidates
or winds-up its business or affairs,



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then, and in each such case, the Company will mail or cause to be mailed to the
Registered Holder of this Warrant a notice specifying, as the case may be, (i)
the date on which a record is to be taken for the purpose of such dividend,
distribution or right, and stating the amount and character of such dividend,
distribution or right, and (ii) the effective date on which such reorganization,
reclassification, consolidation, merger, transfer, dissolution, liquidation or
winding-up is expected to take place, and the record date for determining
shareholders entitled to vote thereon. Such notice shall be mailed at least ten
(10) calendar days prior to the record date or effective date for the event
specified in such notice.

      7.    RESERVATION OF STOCK. The Company shall at all times reserve and
keep available, solely for the issuance and delivery upon the exercise of this
Warrant, such shares of Warrant Stock or other stock or securities, as from time
to time shall be issuable upon the exercise of this Warrant.

      8.    EXCHANGE OF WARRANTS. Upon the surrender by the Registered Holder of
any Warrant, properly endorsed, to the Company at the principal office of the
Company, the Company will, subject to the provisions of Section 3(a) hereof,
issue and deliver to permitted individuals under Section 2.1(g) of that certain
Securities Purchase Agreement, dated as of even date herewith, by and between
the Company and the Registered Holder, at the Company's expense, a new warrant
in a form substantially similar to this Warrant, in the name of such Registered
Holder or as such Registered Holder (upon payment by such Registered Holder of
any applicable transfer taxes) may direct, calling in the aggregate on the face
thereof for the number of shares of Common Stock called for on the face of the
Warrant so surrendered.

      9.    REPLACEMENT OF WARRANTS. Upon receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of loss, theft or destruction, upon delivery of an
indemnity agreement, with surety if reasonably required, in an amount reasonably
satisfactory to the Company, or, in the case of mutilation, upon surrender and
cancellation of this Warrant, the Company will issue, in lieu thereof, a new
warrant in a form substantially similar to this Warrant.

      10.   MAILING OF NOTICES. Any notice required or permitted by this Warrant
shall be in writing and shall be deemed sufficient upon receipt, when delivered
personally or by a nationally-recognized delivery service (such as Federal
Express or UPS) or confirmed facsimile, or forty-eight (48) hours after being
deposited in the U.S. mail as certified or registered mail with postage prepaid,
if such notice is addressed to the party to be notified at such party's address
or facsimile number as set forth below or as subsequently modified by written
notice.



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      11.   NO RIGHTS AS STOCKHOLDER. Until the exercise of this Warrant, the
Registered Holder of this Warrant shall not have or exercise any rights by
virtue hereof as a stockholder of the Company (including without limitation the
right to notification of stockholder meetings or the right to receive any notice
or other communication concerning the business or affairs of the Company).

      12.   AMENDMENT OR WAIVER. Any term of this Warrant may be amended or
waived only by an instrument in writing signed by the party against which
enforcement of the amendment or waiver is sought.

      13.   HEADINGS. The headings in this Warrant are for purposes of reference
only and shall not limit or otherwise affect the meaning of any provision of
this Warrant.

      14.   SUCCESSORS AND ASSIGNS. The terms and provisions of this Warrant
shall inure to the benefit of, and be binding upon, the Company and the
Registered Holder and their respective permitted successors and assigns (in the
case of the Registered Holder, in accordance with Section 3(a) hereof).

      16.   GOVERNING LAW. This Warrant shall be governed, construed and
interpreted in accordance with the laws of the State of California, without
giving effect to principles of conflicts of law thereof.



GERON CORPORATION                         REGISTERED HOLDER


By: /s/ DAVID L. GREENWOOD                Signature: /s/ EVE M. PATTON
   --------------------------------                 ---------------------------

Name: David L. Greenwood                  Name: Eve M. Patton
Title: Chief Financial Officer            Address: Penthouse 28A,
Address: Geron Corporation                Harston Tower
         230 Constitution Drive           109 Repulse Bay Road
         Menlo Park, CA 94025             Hong Kong, China


Facsimile: (650) 473-8654                 Facsimile: (011) 852-2813-1899
                                                            (Hong Kong)
Dated:  March 9, 2000                     Dated: March 9th, 2000



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                                    EXHIBIT A

                                  PURCHASE FORM


To:   GERON CORPORATION

Date: ___________________

      The undersigned, pursuant to the provisions set forth in the attached
Warrant, hereby irrevocably elects to purchase ___________ shares of the Common
Stock covered by such Warrant and herewith makes payment of $___________,
representing the full purchase price for such shares at the price per share
provided for in such Warrant.

      The undersigned hereby affirms and acknowledges the investment
representations and warranties made in the Warrant are true and correct as of
the date hereof, and accepts such shares subject to the restrictions of the
Warrant, copies of which are available from the Secretary of the Company.


Signature: __________________________

Name:

Title:

Address:



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                                    EXHIBIT B

                                 ASSIGNMENT FORM



FOR VALUE RECEIVED, ___________________ hereby sells, assigns and transfers all
of the rights of the undersigned under the attached Warrant with respect to the
number of shares of Common Stock covered thereby set forth below, unto:

<TABLE>
<CAPTION>
NAME OF ASSIGNEE                       ADDRESS                   No. OF SHARES
----------------                       -------                   -------------
<S>                                    <C>                       <C>


</TABLE>


Signature: _______________________________


Witness: _________________________________


Dated: _____________________



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