Document:

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                                                                   Exhibit 10.6

                             STOCK PLEDGE AGREEMENT

         THIS STOCK PLEDGE AGREEMENT (this "Agreement") dated as of December 22,
2000 by _______________, an individual residing at _______________ (the
"Pledgor"), for the benefit of WATTAGE MONITOR INC., a Nevada corporation (the
"Pledgee").

                              W I T N E S S E T H:
                              - - - - - - - - - -

         WHEREAS, pursuant to that certain Stock Purchase Agreement among
Wattage Monitor Inc., Gerald R. Alderson, Vicki Center, Robert Forrest dated as
of the date hereof (the "Stock Purchase Agreement"), Pledgor has acquired
__________ shares of the Pledgee's common stock, par value of $.01 per share
(the "Securities").

         WHEREAS, as consideration for the acquisition of the Pledged
Securities, the Pledgor has executed and delivered to the Pledgee, a secured
promissory note in the principal amount of ____________ Dollars ($______), dated
as of the date hereof (the "Promissory Note"); and

         WHEREAS, the Pledgee requires, and the Pledgor is willing as a
condition to the consummation of the transaction contemplated by the Stock
Purchase Agreement and the Promissory Note to pledge to the Pledgee the
Securities (the "Pledged Securities") as security for the payment and
performance by Pledgor of all of Pledgor's obligations under the Promissory Note
(the "Obligations") by executing and delivering this Agreement.

         NOW, THEREFORE, in consideration of the premises, and in order to
induce the Pledgee to accept the Promissory Note, the Pledgor does hereby agree
as follows:

         Section 1. PLEDGE. The Pledgor hereby irrevocably and unconditionally
pledges to the Pledgee, and grants to the Pledgee a security interest in the
Pledged Securities.

         Section 2. SECURITY FOR OBLIGATIONS. This Agreement secures the
Obligations and all obligations of the Pledgor now or hereafter existing under
this Agreement (all such obligations of the Pledgor being the "Obligations").

         Section 3. DELIVERY OF PLEDGED SECURITIES. The Pledgor shall take all
necessary actions to ensure that all certificates or instruments representing or
evidencing the Pledged Securities shall be delivered to and held by the Pledgee
pursuant hereto and shall be in suitable form for transfer by delivery, or shall
be accompanied by duly executed, notarized instruments of transfer or assignment
in blank, all in form and substance

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satisfactory to the Pledgee. The Pledgee shall have the right, effective
immediately upon failure by the Pledgor to perform the Obligations, in its
discretion and without notice to the Pledgor, to transfer to or to register in
the name of the Pledgee or any of its nominees any or all of the Pledged
Securities. In addition, the Pledgee shall have the right at any time to
exchange certificates or instruments representing or evidencing Pledged
Securities for certificates or instruments of smaller or larger denominations.

         Section 4. REPRESENTATIONS AND WARRANTIES. The Pledgor represents and
warrants that:

                  (a) the pledge of the Pledged Securities pursuant to this
Agreement and delivery of certificates for the Pledged Securities creates a
valid and perfected first priority security interest in the Pledged Securities,
securing the Obligations;

                  (b) no authorization, approval, or other action by, and no
notice to or filing with, any governmental authority or regulatory body is
required either (i) for the pledge by the Pledgor of the Pledged Securities
pursuant to this Agreement or for the execution, delivery or performance of this
Agreement by the Pledgor or (ii) for the remedies in respect of the Pledged
Securities pursuant to this Agreement;

                  (c) the execution, delivery and performance of this Agreement
do not contravene any legal or contractual restriction binding on or affecting
the Pledgor or the Pledged Securities; and

                  (d) this Agreement has been duly executed and delivered by the
Pledgor and constitutes the legal, valid and binding obligation of the Pledgor,
enforceable against the Pledgor in accordance with its terms, subject to the
qualification, however, that the enforcement of the rights and remedies herein
is subject to bankruptcy and other similar laws of general application affecting
rights and remedies of creditors and that the remedy of specific performance or
of injunctive relief is subject to the discretion of the court before which any
proceedings therefor may be brought.

         Section 5. FURTHER ASSURANCES. The Pledgor agrees that at any time and
from time to time, at the expense of the Pledgor, the Pledgor will promptly
execute and deliver all further instruments and documents, and take all further
action, that may be necessary or desirable, or that the Pledgee may request, in
order to perfect and protect any security interest granted or purported to be
granted hereby or to enable the Pledgee to exercise and enforce its rights and
remedies hereunder with respect to any Pledged Securities.

         Section 6.  VOTING RIGHTS, DIVIDENDS, ETC.

                  (a) Unless the Pledgor has failed to perform any of the
Obligations:

                           (i) the Pledgor shall be entitled to exercise any and
                  all voting and other consensual rights pertaining to the
                  Pledged Securities or any part

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                  thereof for any purpose not inconsistent with this Agreement;
                  PROVIDED, HOWEVER, that, the Pledgor shall not exercise or
                  shall refrain from exercising any such right if, in the
                  Pledgee's judgment, such action would be inconsistent with or
                  violate any provisions of this Agreement;

                           (ii) the Pledgee shall exercise and deliver (or cause
                  to be executed or delivered) to the Pledgor all such proxies
                  and other instruments as the Pledgor may reasonably request
                  for the purpose of enabling the Pledgor to exercise the voting
                  and other rights which it is entitled to exercise pursuant to
                  subsection (i) above; and

                           (iii) the Pledgor shall be entitled to receive and
                  retain dividends, distributions or any other payments in
                  respect of the Pledged Securities; PROVIDED, HOWEVER, that,
                  any such dividend, distribution or other payment shall be
                  applied to any balance remaining due under the Promissory
                  Note.

                  (b) Upon the failure of the Pledgor to perform any of the
Obligations, all rights of the Pledgor to exercise the voting and other
consensual rights which it would otherwise be entitled to exercise pursuant to
Section 6(a)(i) hereof shall cease, and the Pledgor shall thereupon have no
further right to exercise such voting and other consensual rights.

         Section 7. TRANSFERS AND OTHER LIENS; ADDITIONAL SHARES. Without
concurrently satisfying all the Obligations, the Pledgor agrees that it will not
(a) sell or otherwise dispose of, or grant any option with respect to, any of
the Pledged Securities, or (b) create or permit to exist any lien, security
interest, or other charge or encumbrance upon or with respect to any of the
Pledged Securities except for the security interest under this Agreement.

         Section 8.  PLEDGEE MAY PERFORM.

                  (a) If the Pledgor fails to perform any agreement contained
herein, the Pledgee may itself perform, or cause performance of, such agreement
and the expenses of the Pledgee incurred in connection therewith shall be
payable by the Pledgor under Section 10 hereof.

                  (b) The Pledgee shall have no responsibility for (i)
ascertaining or taking action with respect to conversions, exchanges, tenders or
other matters relative to any Pledged Securities, whether or not the Pledgee has
or is deemed to have knowledge of such matters, or (ii) taking any necessary
steps to preserve rights against any parties with respect to any Pledged
Securities.

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         Section 9.  REMEDIES UPON FAILURE TO PERFORM THE OBLIGATION.

                  (a) If the Pledgor shall have failed to perform any of the
Obligations, the Pledgee may exercise in respect of the Pledged Securities, in
addition to other rights and remedies provided for herein or otherwise available
to it, all the rights and remedies of a secured party upon default under the
Uniform Commercial Code in effect at that time, and the Pledgee may also,
without notice except as specified below, cancel the shares representing Pledged
Securities or sell the Pledged Securities at public or private sale, at any
exchange, broker's board or elsewhere, for cash, on credit or for future
delivery, and upon such other terms as the Pledgee may deem commercially
reasonable. The Pledgor agrees that, to the extent notice of sale shall be
required by law, at least ten days' notice to the Pledgor of the time and place
of any public sale or the time after which any private sale is to be made shall
constitute reasonable notification. The Pledgee shall not be obligated to make
any sale of Pledged Securities regardless of notice of sale having been given.
The Pledgee may adjourn any public or private sale from time to time by
announcement at the time and place fixed therefor, and such sale may, without
further notice, be made at the time and place to which it was so adjourned.

                  (b) The Pledgor acknowledges that the Pledgee may be unable to
effect a public sale of some or all the Pledged Securities by reason of certain
prohibitions contained in the Securities Act of 1933, as amended (the
"Securities Act") and applicable state securities laws, and may be compelled to
resort to one or more private sales thereof to a restricted group of purchasers
who will be obliged to agree, among other things, to acquire such securities for
their own account for investment and not with a view to the distribution and
resale thereof. The Pledgor acknowledges and agrees that any such private sale
may result in prices and other terms less favorable to the Pledgee than if such
sale were a public sale and, notwithstanding such circumstances, agrees that any
such private sale shall be deemed to have been made in a commercially reasonable
manner. The Pledgee shall be under no obligation to delay a sale of any of the
Pledged Securities for the period of time necessary to permit the registration
of such securities for public sale under the Securities Act, or under applicable
state securities laws, or to cause such registration for public sale to occur.

                  (c) All cash proceeds received by the Pledgee in respect of
any sale of, collection from, or other realization upon all or any part of the
Pledged Securities may, in the discretion of the Pledgee, be held by the Pledgee
as collateral for, and/or then or at any time thereafter applied (after payment
of any amounts payable to the Pledgee pursuant to Section 10 hereof) in whole or
in part by the Pledgee to the payment of the Promissory Note. Any surplus of
such cash or cash proceeds held by the Pledgee and remaining after payment in
full of the Promissory Note shall be paid over to the Pledgor or to whomsoever
may be lawfully entitled to receive such surplus.

         Section 10. EXPENSES. The Pledgor shall indemnify and hold harmless the
Pledgee from and against all claims, damages, liabilities and expenses, and will
upon demand pay to the Pledgee the amount of any and all reasonable expenses,
including the

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reasonable fees and expenses of its counsel and of any experts and agents, which
the Pledgee may incur in connection with (a) the administration or enforcement
of this Agreement, (b) the custody or preservation of, or the sale of,
collection from, or other realization upon, any of the Pledged Securities (c)
the exercise or enforcement of any of the rights of the Pledgee hereunder, or
(d) the failure by the Pledgor to perform or observe any of the provisions
hereof; provided that the Pledgor shall only indemnify and hold harmless the
Pledgee under this Section 10 to the extent such claims, damages, liabilities
and expenses are incurred due to Pledgor's gross negligence, bad faith or
willful misconduct.

         Section 11.  ADDRESSES FOR NOTICES.

                  Any notice, request or other communication under or with
respect to this Agreement shall be in writing and shall be deemed effective upon
receipt if delivered personally (including by fax if a confirmation copy of such
notice is delivered promptly by mail) or sent by registered or certified mail,
return receipt requested, postage prepaid, to either party at its address set
forth below:

                  If to Pledgor:       __________________

                                       __________________

                                       __________________

                  If to Pledgee:       Wattage Monitor Inc.
                                       1100 Kietzke Lane
                                       Reno, Nevada 89502
                                       Attention:

                                       with a copy to:

                                       Willie E. Dennis, Esq.
                                       Akin, Gump, Strauss, Hauer & Feld, L.L.P.
                                       590 Madison Avenue
                                       New York, New York 10022

         Section 12.  CONTINUING SECURITY INTEREST.

                  (a) Notwithstanding anything to the contrary herein contained,
this Agreement, the Obligations and the security interest granted hereunder
shall continue to be effective or reinstated, as the case may be, if at any time
any payment, or any part thereof, of any or all of the Obligations is rescinded,
invalidated, declared to be fraudulent or preferential or otherwise required to
be restored or returned by the Pledgee in connection with any bankruptcy,
reorganization or similar proceeding involving the Pledgor, if the proceeds of
any Pledged Securities are required to be returned by the Pledgee under any such
circumstances, or if the Pledgor elects to return any such payment

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or proceeds or any part thereof in its sole discretion, all as though such
payment had not been made or such proceeds not been received. Without limiting
the generality of the foregoing, if prior to any such rescission, invalidation,
declaration, restoration or return, this Agreement shall have been canceled or
surrendered or the security interest granted hereunder or any Pledged Securities
shall have been released or terminated in connection with such cancellation or
surrender, this Agreement, the security interest and Pledged Securities shall be
reinstated in full force and effect, and such prior cancellation or surrender
shall not diminish, discharge or otherwise affect the obligations of the Pledgor
in respect of the amount of the affected payment or application of proceeds, the
security interest or such Pledged Securities.

                  (b) This Agreement shall create a continuing security interest
in the Pledged Securities and, except as provided below, the security interest
granted hereunder and all agreements, made herein shall survive until, and this
Agreement shall terminate only upon, the indefeasible payment and performance in
full of the Obligations. Upon the indefeasible payment and performance of all of
the Obligations, the Pledgee shall deliver executed termination statements in
appropriate form and any other documents reasonably requested by the Pledgor to
evidence the termination of the security interest in the Pledged Securities. Any
purported termination of this Agreement shall not affect this Agreement in
relation to (i) any Obligation that was incurred or arose prior to the effective
time of such indefeasible payment and performance, (ii) any Obligation incurred
or arising after such effective time where such Obligation is incurred or arises
either pursuant to commitments existing at such effective time or incurred for
the purpose of protecting or enforcing rights against the Pledgor or any other
security given for the Obligations or any portion thereof or (iii) any renewals,
extensions, readvances, modifications or rearrangements of any of the foregoing.

         Section 13.  SECURITY INTEREST ABSOLUTE.

                  (a) All rights of the Pledgee and security interests
hereunder, and all obligations of the Pledgor hereunder, shall be absolute and
unconditional irrespective of:

                           (i)   any lack of validity or enforceability of the
                  Promissory Note or any other agreement or instrument relating
                  thereto; or

                           (ii)  any change in the time, manner or place of
                  payment of, or in any other term of, all or any of the
                  Promissory Note; or any other amendment or waiver of or any
                  consent to any departure from the Promissory Note or any other
                  agreement or instrument relating thereto; or

                           (iii) any exchange, release or non-perfection of any
                  other collateral, or any release or amendment or waiver of or
                  consent to departure from all or any of the Promissory Note;
                  or

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                           (iv)  any other circumstance which might otherwise
                  constitute a defense available to, or a discharge of, a third
                  party pledgor.

                  (b)      The Pledgor hereby waives:

                           (i)   the right to require the Pledgee to proceed
                  against the Pledgor or any other person, to proceed against or
                  exhaust any other collateral or to pursue any other remedy in
                  the Pledgee's power whatsoever and the right to have the
                  property of any other person first applied to the discharge of
                  the Obligations;

                           (ii)  the benefit of any statute of limitations
                  affecting the Obligations or its liability hereunder;

                           (iii) any requirement of marshaling or any other
                  principle of election of remedies;

                           (iv)  except as otherwise specified herein, all
                  notices of any kind, including (A) notice of any action taken
                  or omitted by the Pledgee in reliance hereon, and (B) notice
                  of any action against the Pledgor, or any enforcement or other
                  action with respect to any Pledged Securities or other
                  collateral, or the assertion of any right of the Pledgee; and

                           (v)   all defenses that at any time may be available
                  to the Pledgor by virtue of any valuation, stay, moratorium
                  or other law now or hereafter in effect.

         Section 14. GOVERNING LAW. This Agreement shall be governed by, and
construed in accordance with, the laws of the State of New York without regard
to principles of conflicts of law.

         Section 15. WAIVER. No failure or delay on the part of the Pledgee in
exercising any right, power or privilege under this Agreement and no course of
dealing between the Pledgor and the Pledgee shall operate as a waiver thereof;
nor shall any single or partial exercise of any right, power or privilege
hereunder preclude any other or further notice or demand in similar or other
circumstances or constitute a waiver of the right of the Pledgee to any other or
further action in any circumstances without notice or demand.

         Section 16. DESCRIPTIVE HEADINGS. The descriptive headings of the
several sections of this Agreement are inserted for convenience only and shall
not be deemed to affect the meaning or construction of any of the provisions
hereof.

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         IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed and delivered as of the date first above written.

                                            PLEDGOR

                                            ____________________________
                                            Name:

                                            PLEDGEE

                                            WATTAGE MONITOR INC.

                                            By: ____________________________
                                                   Name:
                                                   Title:

                                       8<PAGE>

                                                                     EXHIBIT 4.2

                                                                     NO. PW-____

         THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR
INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED OR ANY STATE SECURITIES LAWS. SUCH SECURITIES MAY NOT BE SOLD OR
TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN EXEMPTION THEREFROM UNDER
SAID ACT AND ANY APPLICABLE STATE SECURITIES LAWS.

                      WARRANT TO PURCHASE __________ SHARES
                         OF SERIES B PREFERRED STOCK OF
                               DNA SCIENCES, INC.
                           (VOID AFTER APRIL __, 2004)

         This certifies that ______________ or its assigns (the "Holder"), for
value received, is entitled to purchase from DNA Sciences, Inc., a Delaware
corporation (the "Company"), having a place of business at 2375 Garcia Avenue,
Mountain View, CA 94043, a maximum of __________ fully paid and nonassessable
shares of the Company's Series B Preferred Stock (the "Series B Preferred") for
cash at a price of _________ per share (the "Exercise Price") at any time or
from time to time up to and including 5:00 p.m. (Pacific time) four (4) years
from the date of this Warrant, such day being referred to herein as the
"Expiration Date," upon surrender to the Company at its principal office (or at
such other location as the Company may advise the Holder in writing) of this
Warrant properly endorsed with the Form of Subscription attached hereto duly
filled in and signed and, if applicable, upon payment in cash or by check of the
aggregate Exercise Price for the number of shares for which this Warrant is
being exercised determined in accordance with the provisions hereof. The
Exercise Price and the number of shares purchasable hereunder are subject to
adjustment as provided in Section 3 of this Warrant.

         This Warrant is subject to the following terms and conditions:

         1. EXERCISE; ISSUANCE OF CERTIFICATES; PAYMENT FOR SHARES.

              1.1 GENERAL. This Warrant is exercisable at the option of the
holder of record hereof, at any time or from time to time, up to the Expiration
Date for all or any part of the shares of Series B Preferred (but not for a
fraction of a share) which may be purchased hereunder. The Company agrees that
the shares of Series B Preferred purchased under this Warrant shall be and are
deemed to be issued to the Holder hereof as the record owner of such shares as
of the close of business on the date on which this Warrant shall have been
surrendered, properly endorsed, the completed, executed Form of Subscription
delivered and payment made for such shares. Certificates for the shares of
Series B Preferred so purchased, together with any other securities or property
to which the Holder hereof is entitled upon such exercise, shall be delivered to
the Holder hereof by the Company at the Company's expense within a reasonable
time after the rights represented by this Warrant have been so exercised. In
case of a purchase of less than all the shares which may be purchased under this
Warrant, the Company shall cancel this Warrant and execute and deliver a new
Warrant or Warrants of like tenor for the balance of the shares purchasable
under the Warrant surrendered upon such purchase to the Holder hereof
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within a reasonable time. Each Series B Preferred certificate so delivered shall
be in such denominations of Series B Preferred as may be requested by the Holder
hereof and shall be registered in the name of such Holder.

              1.2 NET ISSUE EXERCISE. Notwithstanding any provisions herein to
the contrary, if the fair market value of one share of Series B Preferred is
greater than the Exercise Price (at the date of calculation as set forth below)
in lieu of exercising this Warrant for cash, the Holder may elect to receive
shares equal to the value (as determined below) of this Warrant (or the portion
thereof being canceled) by surrender of this Warrant at the principal office of
the Company together with notice of such election, in which event the Company
shall issue to the Holder a number of shares of Series B Preferred computed
using the following formula:

                  X = Y (A - B)
                      ---------
                         A

                                    Where X = the number of shares of Series B
                                    Preferred to be issued to the Holder

                                              Y = the number of shares of Series
                                    B Preferred purchasable under the Warrant
                                    or, if only a portion of the Warrant is
                                    being exercised, the number of shares of
                                    Series B Preferred purchased under the
                                    Warrant being canceled (at the date of such
                                    calculation)

                                              A = the fair market value of one
                                    share of the Company's Series B Preferred
                                    Stock (at the date of such calculation, as
                                    provided below)

                                              B = Exercise Price (as adjusted to
                                    the date of such calculation)

         For purposes of the above calculation, the fair market value of one
share of Series B Preferred shall be determined by the Company's Board of
Directors in good faith; PROVIDED, HOWEVER, that where there is a public market
for the Company's Common Stock and the Company's Series B Preferred Stock has
converted into such Common Stock, the fair market value per share shall be the
product of (i) the average of the closing prices (or bid prices if there are no
such closing prices) of the Company's Common Stock quoted in the
Over-The-Counter Market Summary or the closing price quoted on The Nasdaq
National Market System or on the primary national securities exchange on which
the Common Stock is then listed, whichever is applicable, as published in the
Western Edition of the Wall Street Journal (or, if not so reported, as otherwise
reported by The Nasdaq System) for the ten (10) trading days prior to the date
of determination of fair market value and (ii) the number of shares of Common
Stock into which each share of Series B Preferred is convertible at the time of
such exercise.

         2. SHARES TO BE FULLY PAID; RESERVATION OF SHARES. The Company
covenants and agrees that all shares of Series B Preferred which may be issued
upon the exercise of the rights represented by this Warrant will, upon issuance,
be duly authorized, validly issued, fully paid and nonassessable and free from
all preemptive rights of any shareholder and free of all

                                       2.
<PAGE>

taxes, liens and charges with respect to the issue thereof. The Company further
covenants and agrees that, during the period within which the rights represented
by this Warrant may be exercised, the Company will at all times have authorized
and reserved, for the purpose of issue or transfer upon exercise of the
subscription rights evidenced by this Warrant, a sufficient number of shares of
authorized but unissued Series B Preferred, or other securities and property,
when and as required to provide for the exercise of the rights represented by
this Warrant. The Company will take all such action as may be necessary to
assure that such shares of Series B Preferred may be issued as provided herein
without violation of any applicable law or regulation, or of any requirements of
any domestic securities exchange upon which the Series B Preferred may be
listed; provided, however, that the Company shall not be required to effect a
registration under Federal or State securities laws with respect to such
exercise. The Company will not take any action which would result in any
adjustment of the Exercise Price (as set forth in Section 3 hereof) (i) if the
total number of shares of Series B Preferred issuable after such action upon
exercise of all outstanding warrants, together with all shares of Series B
Preferred then outstanding and all shares of Series B Preferred then issuable
upon exercise of all options and upon the conversion of all convertible
securities then outstanding, would exceed the total number of shares of Series B
Preferred then authorized by the Company's Restated Certificate of
Incorporation, or (ii) if the total number of shares of Series B Preferred
issuable after such action upon the conversion of all such shares of Series B
Preferred, together with all shares of Common Series B Preferred then issuable
upon exercise of all options and upon the conversion of all such shares of
Series B Preferred, together with all shares of Common stock then outstanding
and all shares of Common Stock then issuable upon exercise of all options and
upon the conversion of all convertible securities then outstanding would exceed
the total number of shares of Common Stock then authorized by the Company's
Restated Certificate of Incorporation.

         3. ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF SHARES. The Exercise
Price and the number of shares purchasable upon the exercise of this Warrant
shall be subject to adjustment from time to time upon the occurrence of certain
events described in this Section 3. Upon each adjustment of the Exercise Price,
the Holder of this Warrant shall thereafter be entitled to purchase, at the
Exercise Price resulting from such adjustment, the number of shares obtained by
multiplying the Exercise Price in effect immediately prior to such adjustment by
the number of shares purchasable pursuant hereto immediately prior to such
adjustment, and dividing the product thereof by the Exercise Price resulting
from such adjustment.

              3.1 SUBDIVISION OR COMBINATION OF SERIES B PREFERRED. In case the
Company shall at any time subdivide its outstanding shares of Series B Preferred
into a greater number of shares, the Exercise Price in effect immediately prior
to such subdivision shall be proportionately reduced, and conversely, in case
the outstanding shares of Series B Preferred of the Company shall be combined
into a smaller number of shares, the Exercise Price in effect immediately prior
to such combination shall be proportionately increased.

              3.2 DIVIDENDS IN SERIES B PREFERRED, OTHER STOCK, PROPERTY,
RECLASSIFICATION. If at any time or from time to time the Holders of Series B
Preferred (or any shares of stock or other securities at the time receivable
upon the exercise of this Warrant) shall have received or become entitled to
receive, without payment therefor,

                                       3.
<PAGE>

                  (a) Series B Preferred or any shares of stock or other
securities which are at any time directly or indirectly convertible into or
exchangeable for Series B Preferred, or any rights or options to subscribe for,
purchase or otherwise acquire any of the foregoing by way of dividend or other
distribution,

                  (b) any cash paid or payable otherwise than as a cash
dividend, or

                  (c) Series B Preferred or additional stock or other securities
or property (including cash) by way of spinoff, split-up, reclassification,
combination of shares or similar corporate rearrangement, (other than shares of
Series B Preferred issued as a stock split or adjustments in respect of which
shall be covered by the terms of Section 3.1 above), then and in each such case,
the Holder hereof shall, upon the exercise of this Warrant, be entitled to
receive, in addition to the number of shares of Series B Preferred receivable
thereupon, and without payment of any additional consideration therefor, the
amount of stock and other securities and property (including cash in the cases
referred to in clause (b) above and this clause (c)) which such Holder would
hold on the date of such exercise had he been the holder of record of such
Series B Preferred as of the date on which holders of Series B Preferred
received or became entitled to receive such shares or all other additional stock
and other securities and property.

              3.3 REORGANIZATION, RECLASSIFICATION, CONSOLIDATION, MERGER OR
SALE. If any recapitalization, reclassification or reorganization of the capital
stock of the Company, or any consolidation or merger of the Company with another
corporation, or the sale of all or substantially all of its assets or other
transaction shall be effected in such a way that holders of Series B Preferred
shall be entitled to receive Series B Preferred, securities, or other assets or
property (an "Organic Change"), then, as a condition of such Organic Change,
lawful and adequate provisions shall be made by the Company whereby the Holder
hereof shall thereafter have the right to purchase and receive (in lieu of the
shares of the Series B Preferred of the Company immediately theretofore
purchasable and receivable upon the exercise of the rights represented hereby)
such shares of stock, securities or other assets or property as may be issued or
payable with respect to or in exchange for a number of outstanding shares of
such Series B Preferred equal to the number of shares of such stock immediately
theretofore purchasable and receivable upon the exercise of the rights
represented hereby; provided, however, that in the event the value of the stock,
securities or other assets or property (determined in good faith by the Board of
Directors of the Company) issuable or payable with respect to one share of the
Series B Preferred of the Company immediately theretofore purchasable and
receivable upon the exercise of the rights represented hereby is in excess of
the Exercise Price hereof effective at the time of a merger and securities
received in such reorganization, if any, are publicly traded, then this Warrant
shall expire unless exercised prior to such Organic Change. In the event of any
Organic Change, appropriate provision shall be made by the Company with respect
to the rights and interests of the Holder of this Warrant to the end that the
provisions hereof (including, without limitation, provisions for adjustments of
the Exercise Price and of the number of shares purchasable and receivable upon
the exercise of this Warrant) shall thereafter be applicable, in relation to any
shares of stock, securities or assets thereafter deliverable upon the exercise
hereof. The Company will not effect any such consolidation, merger or sale
unless, prior to the consummation thereof, the successor corporation (if other
than the Company) resulting from such consolidation or the corporation
purchasing such assets shall assume, by written instrument reasonably
satisfactory in form and substance to the Holder, the obligation to deliver to
the

                                       4.
<PAGE>

Holder such shares of stock, securities or assets as, in accordance with the
foregoing provisions, the Holder may be entitled to purchase.

              3.4 CERTAIN EVENTS. If any change in the outstanding Series B
Preferred of the Company or any other event occurs as to which the other
provisions of this Section 3 are not strictly applicable or if strictly
applicable would not fairly protect the purchase rights of the Holder of the
Warrant in accordance with such provisions, then the Board of Directors of the
Company shall make an adjustment in the number and class of shares available
under the Warrant, the Exercise Price or the application of such provisions, so
as to protect such purchase rights as aforesaid. The adjustment shall be such as
will give the Holder of the Warrant upon exercise for the same aggregate
Exercise Price the total number, class and kind of shares as he would have owned
had the Warrant been exercised prior to the event and had he continued to hold
such shares until after the event requiring adjustment.

              3.5 NOTICES OF CHANGE.

                  (a) Immediately upon any adjustment in the number or class of
shares subject to this Warrant and of the Exercise Price, the Company shall give
written notice thereof to the Holder, setting forth in reasonable detail and
certifying the calculation of such adjustment.

                  (b) The Company shall give written notice to the Holder at
least 10 business days prior to the date on which the Company closes its books
or takes a record for determining rights to receive any dividends or
distributions.

                  (c) The Company shall also give written notice to the Holder
at least 30 business days prior to the date on which an Organic Change shall
take place.

         4. ISSUE TAX. The issuance of certificates for shares of Series B
Preferred upon the exercise of the Warrant shall be made without charge to the
Holder of the Warrant for any issue tax (other than any applicable income taxes)
in respect thereof; provided, however, that the Company shall not be required to
pay any tax which may be payable in respect of any transfer involved in the
issuance and delivery of any certificate in a name other than that of the then
Holder of the Warrant being exercised.

         5. CLOSING OF BOOKS. The Company will at no time close its transfer
books against the transfer of any warrant or of any shares of Series B Preferred
issued or issuable upon the exercise of any warrant in any manner which
interferes with the timely exercise of this Warrant.

         6. NO VOTING OR DIVIDEND RIGHTS; LIMITATION OF LIABILITY. Nothing
contained in this Warrant shall be construed as conferring upon the Holder
hereof the right to vote or to consent or to receive notice as a shareholder of
the Company or any other matters or any rights whatsoever as a shareholder of
the Company. No dividends or interest shall be payable or accrued in respect of
this Warrant or the interest represented hereby or the shares purchasable
hereunder until, and only to the extent that, this Warrant shall have been
exercised. No provisions hereof, in the absence of affirmative action by the
holder to purchase shares of Series B Preferred, and no mere enumeration herein
of the rights or privileges of the holder hereof, shall give rise to any
liability of such Holder for the Exercise Price or as a shareholder of the
Company, whether such liability is asserted by the Company or by its creditors.

                                       5.
<PAGE>

         7. WARRANTS TRANSFERABLE. Subject to compliance with applicable federal
and state securities laws, this Warrant and all rights hereunder are
transferable, in whole or in part, without charge to the holder hereof (except
for transfer taxes), upon surrender of this Warrant properly endorsed. Each
taker and holder of this Warrant, by taking or holding the same, consents and
agrees that this Warrant, when endorsed in blank, shall be deemed negotiable,
and that the holder hereof, when this Warrant shall have been so endorsed, may
be treated by the Company, at the Company's option, and all other persons
dealing with this Warrant as the absolute owner hereof for any purpose and as
the person entitled to exercise the rights represented by this Warrant, or to
the transfer hereof on the books of the Company any notice to the contrary
notwithstanding; but until such transfer on such books, the Company may treat
the registered owner hereof as the owner for all purposes.

         8. MARKET STAND-OFF AGREEMENT. Holder shall not sell, dispose of,
transfer, make any short sale of, grant any option for the purchase of, or enter
into any hedging or similar transaction with the same economic effect as a sale,
any Common Stock (or other securities) of the Company held by Holder, for a
period of time specified by the managing underwriter(s) (not to exceed one
hundred eighty (180) days following the effective date of a registration
statement of the Company filed under the Securities Act of 1933. Holder agrees
to execute and deliver such other agreements as may be reasonably requested by
the Company and/or the managing underwriter(s) which are consistent with the
foregoing or which are necessary to give further effect thereto. In order to
enforce the foregoing covenant, the Company may impose stop-transfer
instructions with respect to such Common Stock (or other securities) until the
end of such period.

         9. RIGHTS AND OBLIGATIONS SURVIVE EXERCISE OF WARRANT. The rights and
obligations of the Company, of the holder of this Warrant and of the holder of
shares of Series B Preferred issued upon exercise of this Warrant, shall survive
the exercise of this Warrant.

         10. MODIFICATION AND WAIVER. This Warrant and any provision hereof may
be changed, waived, discharged or terminated only by an instrument in writing
signed by the party against which enforcement of the same is sought.

         11. NOTICES. Any notice, request or other document required or
permitted to be given or delivered to the holder hereof or the Company shall be
delivered or shall be sent by certified mail, postage prepaid, to each such
holder at its address as shown on the books of the Company or to the Company at
the address indicated therefor in the first paragraph of this Warrant or such
other address as either may from time to time provide to the other.

         12. BINDING EFFECT ON SUCCESSORS. This Warrant shall be binding upon
any corporation succeeding the Company by merger, consolidation or acquisition
of all or substantially all of the Company's assets. All of the obligations of
the Company relating to the Series B Preferred issuable upon the exercise of
this Warrant shall survive the exercise and termination of this Warrant. All of
the covenants and agreements of the Company shall inure to the benefit of the
successors and assigns of the holder hereof.

         13. DESCRIPTIVE HEADINGS AND GOVERNING LAW. The description headings of
the several sections and paragraphs of this Warrant are inserted for convenience
only and do not

                                       6.
<PAGE>

constitute a part of this Warrant. This Warrant shall be construed and enforced
in accordance with, and the rights of the parties shall be governed by, the laws
of the State of California.

         14. LOST WARRANTS. The Company represents and warrants to the Holder
hereof that upon receipt of evidence reasonably satisfactory to the Company of
the loss, theft, destruction, or mutilation of this Warrant and, in the case of
any such loss, theft or destruction, upon receipt of an indemnity reasonably
satisfactory to the Company, or in the case of any such mutilation upon
surrender and cancellation of such Warrant, the Company, at its expense, will
make and deliver a new Warrant, of like tenor, in lieu of the lost, stolen,
destroyed or mutilated Warrant.

         15. FRACTIONAL SHARES. No fractional shares shall be issued upon
exercise of this Warrant. The Company shall, in lieu of issuing any fractional
share, pay the holder entitled to such fraction a sum in cash equal to such
fraction multiplied by the then effective Exercise Price.

         16. REGISTRATION RIGHTS. The shares issued upon exercise of this
Warrant shall be included as "Registrable Securities" under the terms of the
Company's Amended and Restated Investor Rights Agreement, dated
_________________ ( the "Investor Rights Agreement") and the holder of such
shares shall entitled to those rights specified in such Investor Rights
Agreement in accordance with the terms therein.

                      [THIS SPACE INTENTIONALLY LEFT BLANK]

                                       7.
<PAGE>

         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed by its officers, thereunto duly authorized this ______ day of
_________, 2000.

                                              DNA SCIENCES, INC.

                                              a Delaware corporation

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

ATTEST:

-----------------------------------

<PAGE>

                                    EXHIBIT A

                                SUBSCRIPTION FORM

                                                 Date: _________________, 20 ___

DNA Sciences, Inc.
2375 Garcia Avenue

Mountain View, CA  94043

Attn:  Chief Executive Officer

Ladies and Gentlemen:

/ /      The undersigned hereby elects to exercise the warrant issued to it by
         DNA Sciences, Inc. (the "Company") and dated ___________, 2000 Warrant
         No. PW-___ (the "Warrant") and to purchase thereunder
         __________________________________ shares of the Series B Stock of the
         Company (the "Shares") at a purchase price of __________ ($____) per
         Share or an aggregate purchase price of
         __________________________________ Dollars ($__________) (the "Purchase
         Price").

/ /      The undersigned hereby elects to convert _______________________
         percent (____%) of the value of the Warrant pursuant to the provisions
         of Section 1.2 of the Warrant.

         Pursuant to the terms of the Warrant the undersigned has delivered the
Purchase Price herewith in full in cash or by certified check or wire transfer.

                                         Very truly yours,

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

                                         Title:
                                                --------------------------------

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