Document:

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                                                                   EXHIBIT 10.3

                              AMENDED AND RESTATED
                            ACLARA BIOSCIENCES, INC.
                                 1997 STOCK PLAN

        1. Purposes of the Plan. The purposes of this 1997 Stock Plan are:

           -   to attract and retain the best available personnel for positions
               of substantial responsibility,

           -   to provide additional incentive to Employees, Consultants and
               Directors, and

           -   to promote the success of the Company's business.

Options granted under the Plan may be Incentive Stock Options or Nonstatutory
Stock Options, as determined by the Administrator at the time of grant. Stock
Purchase Rights may also be granted under the Plan.

        2. Definitions. As used herein, the following definitions shall apply:

           (a) "Administrator" means the Board or any of its Committees as shall
be administering the Plan, in accordance with Section 4 of the Plan.

           (b) "Applicable Laws" means the legal requirements relating to the
administration of stock option plans under U.S. state corporate laws, U.S.
federal and state securities laws, the Code, any stock exchange or quotation
system on which the Common Stock is listed or quoted and the applicable laws of
any foreign country or jurisdiction where Options or Stock Purchase Rights are
granted under the Plan.

           (c) "Board" means the Board of Directors of the Company.

           (d) "Code" means the Internal Revenue Code of 1986, as amended.

           (e) "Committee" means a Committee appointed by the Board in
accordance with Section 4 of the Plan.

           (f) "Common Stock" means the Common Stock of the Company.

           (g) "Company" means ACLARA BioSciences, Inc., a Delaware corporation.

           (h) "Consultant" means any consultant or adviser if: (i) the
consultant or adviser renders bona fide services to the Company; (ii) the
services rendered by the consultant or adviser are not in connection with the
offer or sale of securities in a capital-raising transaction and do not directly
or indirectly promote or maintain a market for the Company's securities; and
(iii) the consultant or adviser is a natural person who has contracted directly
with the Company to render such services.

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           (i) "Continuous Status as an Employee or Consultant" means that the
employment or consulting relationship with the Company, any Parent, or
Subsidiary, is not interrupted or terminated. Continuous Status as an Employee
or Consultant shall not be considered interrupted in the case of (i) any leave
of absence approved by the Company or (ii) transfers between locations of the
Company or between the Company, its Parent, any Subsidiary, or any successor. A
leave of absence approved by the Company shall include sick leave, military
leave, or any other personal leave approved by an authorized representative of
the Company. For purposes of Incentive Stock Options, no such leave may exceed
ninety (90) days, unless reemployment upon expiration of such leave is
guaranteed by statute or contract. If reemployment upon expiration of a leave of
absence approved by the Company is not so guaranteed, on the 181st day of such
leave any incentive Stock Option held by the Optionee shall cease to be treated
as an Incentive Stock Option and shall be treated for tax purposes as a
Nonstatutory Stock Option.

           (j) "Director" means a member of the Board.

           (k) "Disability" means total disability as defined in Section
22(e)(3) of the Code.

           (l) "Employee" means any person, including Officers and Directors,
employed by the Company or any Parent or Subsidiary of the Company. Neither
service as a Director nor payment of a director's fee by the Company shall be
sufficient to constitute "employment" by the Company.

           (m) "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

           (n) "Fair Market Value" means, as of any date, the value of Common
Stock determined as follows:

               (i) If the Common Stock is listed on any established stock
exchange or a national market system, including without limitation the Nasdaq
National Market of the National Association of Securities Dealers, Inc.
Automated Quotation ("Nasdaq") System, the Fair Market Value of a Share of
Common Stock shall be the closing sales price for such stock (or the closing
bid, if no sales were reported) as quoted on such system or exchange (or the
exchange with the greatest volume of trading in Common Stock) on the last market
trading day prior to the day of determination, as reported in The Wall Street
Journal or such other source as the Administrator deems reliable;

               (ii) If the Common Stock is quoted on the Nasdaq System (but not
on the Nasdaq National Market thereof) or is regularly quoted by a recognized
securities dealer but selling prices are not reported, the Fair Market Value of
a Share of Common Stock shall be the mean between the high bid and low asked
prices for the Common Stock on the last market trading day prior to the day of
determination, as reported in The Wall Street Journal or such other source as
the Administrator deems reliable;

               (iii) In the absence of an established market for the Common
Stock, the Fair Market Value shall be determined in good faith by the
Administrator.

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           (o) "Incentive Stock Option" means an Option intended to qualify as
an incentive stock option within the meaning of Section 422 of the Code and the
regulations promulgated thereunder and which is designated as an Incentive Stock
Option by the Administrator.

           (p) "Independent Director" means a Director who is not an Employee of
the Company.

           (q) "Nonstatutory Stock Option" means an Option not intended to
qualify as an Incentive Stock Option and which is not designated as an Incentive
Stock Option by the Administrator.

           (r) "Notice of Grant" means a written notice evidencing certain terms
and conditions of an individual Option or Stock Purchase Right grant. The Notice
of Grant is part of the Option Agreement in the case of an Option and is
accompanied by a Restricted Stock Purchase Agreement in the case of a Stock
Purchase Right.

           (s) "Officer" means a person who is an officer of the Company within
the meaning of Section 16 of the Exchange Act and the rules and regulations
promulgated thereunder.

           (t) "Option" means a stock option granted pursuant to the Plan.

           (u) "Option Agreement" means a written agreement between the Company
and an Optionee evidencing the terms and conditions of an individual Option
grant. The Option Agreement is subject to the terms and conditions of the Plan.

           (v) "Option Exchange Program" means a program whereby outstanding
options are surrendered in exchange for options with a lower exercise price.

           (w) "Optioned Stock" means the Common Stock subject to an Option or
Stock Purchase Right.

           (x) "Optionee" means an Employee or Consultant who holds an
outstanding Option or Stock Purchase Right.

           (y) "Parent" means a "parent corporation," whether now or hereafter
existing, as defined in Section 424(e) of the Code.

           (z) "Permanent Disability" means permanent disability as defined
under Section 10(c) below.

           (aa) "Plan" means this Amended and Restated ACLARA BioSciences, Inc.
1997 Stock Plan.

           (bb) "Public Trading Date" means the first date upon which Common
Stock of the Company is listed (or approved for listing) upon notice of issuance
on any securities exchange or designated (or approved for designation) upon
notice of issuance as a national market security on an interdealer quotation
system.

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           (cc) "Restricted Stock" means shares of Common Stock acquired
pursuant to a grant of Stock Purchase Rights under Section 13 below.

           (dd) "Restricted Stock Purchase Agreement" means a written agreement
between the Company and the Optionee evidencing the terms and restrictions
applying to Common Stock purchased under a Stock Purchase Right. The Restricted
Stock Purchase Agreement is subject to the terms and conditions of the Plan and
the Notice of Grant.

           (ee) "Rule 16b-3" means Rule 16b-3 of the Exchange Act or any
successor to Rule 16b-3, as in effect when discretion is being exercised with
respect to the Plan.

           (ff) "Share" means a share of the Common Stock, as adjusted in
accordance with Section 16 of the Plan.

           (gg) "Stock Purchase Right" means the right to purchase Common Stock
pursuant to Section 13 of the Plan, as evidenced by a Notice of Grant.

           (hh) "Subsidiary" means a "subsidiary corporation," whether now or
hereafter existing, as defined in Section 424(f) of the Code.

        3. Stock Subject to the Plan. Subject to the provisions of Section 16 of
the Plan, the maximum aggregate number of Shares which may be sold or optioned
and sold under the Plan is 3,340,522 Shares; provided, however, that, during
the term of the Plan, on each anniversary of the date of the Plan's adoption by
the Board (commencing with the first such anniversary), such maximum aggregate
number of Shares shall be increased by 750,000 Shares. The Shares may be
authorized, but unissued, or reacquired Common Stock.

           If an Option or Stock Purchase Right expires or becomes unexercisable
without having been exercised in full, or is surrendered pursuant to an Option
Exchange Program, the unpurchased Shares which were subject thereto shall become
available for future grant or sale under the Plan (unless the Plan has
terminated); provided, however, that Shares that have actually been issued under
the Plan, whether upon exercise of an Option or Right, shall not be returned to
the Plan and shall not become available for future distribution under the Plan,
except that if Shares of Restricted Stock are repurchased by the Company at
their original purchase price, and the original purchaser of such Shares did not
receive any benefits of ownership of such Shares, such Shares shall become
available for future grant under the Plan. For purposes of the preceding
sentence, voting rights shall not be considered a benefit of Share ownership.

        4. Administration of the Plan.

           (a) Procedure.

               (i) Multiple Administrative Bodies. If permitted by Rule 16b-3,
the Plan may be administered by different bodies with respect to Directors,
Officers who are not Directors, and Employees who are neither Directors nor
Officers.

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               (ii) Administration With Respect to Directors and Officers
Subject to Section 16(b). With respect to Option or Stock Purchase Right grants
made to Employees who are also Officers or Directors subject to Section 16(b) of
the Exchange Act, the Plan shall be administered by (A) the Board, if the Board
may administer the Plan in compliance with the rules governing a plan intended
to qualify as a discretionary plan under Rule 16b-3, or (B) a committee
designated by the Board to administer the Plan, which committee shall be
constituted to comply with the rules governing a plan intended to qualify as a
discretionary plan under Rule 16b-3. Once appointed, such Committee shall
continue to serve in its designated capacity until otherwise directed by the
Board. From time to time the Board may increase the size of the Committee and
appoint additional members, remove members (with or without cause) and
substitute new members, fill vacancies (however caused), and remove all members
of the Committee and thereafter directly administer the Plan, all to the extent
permitted by the rules governing a plan intended to qualify as a discretionary
plan under Rule 16b-3.

               (iii) Administration With Respect to Other Persons. With respect
to Option or Stock Purchase Right grants made to Employees or Consultants who
are neither Directors nor Officers of the Company, the Plan shall be
administered by (A) the Board or (B) a committee designated by the Board, which
committee shall be constituted to satisfy Applicable Laws. Once appointed, such
Committee shall serve in its designated capacity until otherwise directed by the
Board. The Board may increase the size of the Committee and appoint additional
members, remove members (with or without cause) and substitute new members, fill
vacancies (however caused), and remove all members of the Committee and
thereafter directly administer the Plan, all to the extent permitted by
Applicable Laws.

           (b) Powers of the Administrator. Subject to the provisions of the
Plan, and in the case of a Committee, subject to the specific duties delegated
by the Board to such Committee, the Administrator shall have the authority, in
its discretion:

               (i) to determine the Fair Market Value of the Common Stock, in
accordance with Section 2(n) of the Plan;

               (ii) to select the Consultant, Directors and Employees to whom
Options and Stock Purchase Rights may be granted hereunder;

               (iii) to determine whether and to what extent Options and Stock
Purchase Rights or any combination thereof, are granted hereunder;

               (iv) to determine the number of shares of Common Stock to be
covered by each Option and Stock Purchase Right granted hereunder;

               (v) to approve forms of agreement for use under the Plan;

               (vi) to determine the terms and conditions, not inconsistent with
the terms of the Plan, of any award granted hereunder. Such terms and conditions
include, but are not limited to, the exercise price, the time or times when
Options or Stock Purchase Rights may be exercised (which may be based on
performance criteria), any vesting acceleration or waiver of forfeiture
restrictions, and any restriction or limitation regarding any Option or Stock
Purchase

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Right or the shares of Common Stock relating thereto, based in each case on such
factors as the Administrator, in its sole discretion, shall determine;

               (vii) to reduce the exercise price of any Option or Stock
Purchase Right to the then current Fair Market Value if the Fair Market Value of
the Common Stock covered by such Option or Stock Purchase Right shall have
declined since the date the Option or Stock Purchase Right was granted;

               (viii) to construe and interpret the terms of the Plan and awards
granted pursuant to the Plan;

               (ix) to prescribe, amend and rescind rules and regulations
relating to the Plan, including rules and regulations relating to sub-plans
established for the purpose of qualifying for preferred tax treatment under
foreign tax laws;

               (x) to modify or amend each Option or Stock Purchase Right
(subject to Section 18(c) of the Plan), including the discretionary authority to
extend the post-termination exercisability period of Options longer than is
otherwise provided for in the Plan:

               (xi) to authorize any person to execute on behalf of the Company
any instrument required to effect the grant of an Option or Stock Purchase Right
previously granted by the Administrator;

               (xii) to institute an Option Exchange Program;

               (xiii) to determine the terms and restrictions applicable to
Options and Stock Purchase Rights and any Restricted Stock; and

               (xiv) to make all other determinations deemed necessary or
advisable for administering the Plan.

           (c) Effect of Administrator's Decision. The Administrator's
decisions, determinations and interpretations shall be final and binding on all
Optionees and any other holders of Options or Stock Purchase Rights.

        5. Eligibility. Nonstatutory Stock Options and Stock Purchase Rights may
be granted to Employees, Directors and Consultants. Incentive Stock Options may
be granted only to Employees. If otherwise eligible, an Employee, Director or
Consultant who has been granted an Option or Stock Purchase Right may be granted
additional Options or Stock Purchase Rights.

        6. Limitations.

           (a) Each Option shall be designated in the Notice of Grant as either
an Incentive Stock Option or a Nonstatutory Stock Option. However,
notwithstanding such designations, to the extent that the aggregate Fair Market
Value:

               (i) of Shares subject to an Optionee's Incentive Stock Options
granted by the Company, any Parent or Subsidiary, which

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               (ii) become exercisable for the first time during any calendar
year (under all plans of the Company or any Parent or Subsidiary) exceeds
$100,000, such excess Options shall be treated as Nonstatutory Stock Options.
For purposes of this Section 6(a), Incentive Stock Options shall be taken into
account in the order in which they were granted, and the Fair Market Value of
the Shares shall be determined as of the time of grant.

           (b) Neither the Plan nor any Option or Stock Purchase Right shall
confer upon an Optionee any right with respect to continuing the Optionee's
employment or consulting relationship with the Company, nor shall they interfere
in any way with the Optionee's right or the Company's right to terminate such
employment or consulting relationship at any time, with or without cause.

           (c) The following limitations shall apply to grants of Options and
Stock Purchase Rights to Employees:

               (i) No Employee shall be granted, in any fiscal year of the
Company, Options and Stock Purchase Rights to purchase more than 700,000 Shares;
provided, however, that the foregoing limitation shall not apply prior to the
Public Trading Date and, following the Public Trading Date, the foregoing
limitation shall not apply until the earliest of: (i) the first material
modification of the Plan (including any increase in the number of shares
reserved for issuance under the Plan in accordance with Section 3); (ii) the
issuance of all of the shares of Common Stock reserved for issuance under the
Plan; (iii) the expiration of the Plan; (iv) the first meeting of stockholders
at which Directors of the Company are to be elected that occurs after the close
of the third calendar year following the calendar year in which occurred the
first registration of an equity security of the Company under Section 12 of the
Exchange Act; or (v) such other date required by Section 162(m) of the Code and
the rules and regulations promulgated thereunder. The foregoing limitation shall
be adjusted proportionately in connection with any change in the Company's
capitalization as described in Section 16. For purposes of this Section 6(c), if
an Option is canceled in the same calendar year it was granted (other than in
connection with a transaction described in Section 16), the canceled Option will
be counted against the limit set forth in this Section 6(c). For this purpose,
if the exercise price of an Option is reduced, the transaction shall be treated
as a cancellation of the Option and the grant of a new Option.

               (ii) The foregoing limitations shall be adjusted proportionately
in connection with any change in the Company's capitalization as described in
Section 16.

               (iii) If an Option or Stock Purchase Right is canceled in the
same fiscal year of the Company in which it was granted (other than in
connection with a transaction described in Section 16), the canceled Option or
Stock Purchase Right will be counted against the limit set forth in Section
6(c)(i). For this purpose, if the exercise price of an Option or Stock Purchase
Right is reduced, the transaction will be treated as a cancellation of the
Option or Stock Purchase Right and the grant of a new Option or Stock Purchase
Right.

        7. Term of Plan. Subject to Section 22 of the Plan, the Plan shall
become effective upon the earlier to occur of its adoption by the Board or its
approval by the shareholders of the

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Company as described in Section 22 of the Plan. It shall continue in effect for
a term of ten (10) years unless terminated earlier under Section 18 of the Plan.

        8. Term of Option. The term of each Option shall be stated in the Notice
of Grant; provided, however, that in the case of an Incentive Stock Option, the
term shall be ten (10) years from the date of grant or such shorter term as may
be provided in the Notice of Grant. Moreover, in the case of an Incentive Stock
Option granted to an Optionee who, at the time the Incentive Stock Option is
granted, owns stock representing more than ten percent (10%) of the voting of
all classes of stock of the Company or any Parent or Subsidiary, the term of the
Incentive Stock Option shall be five (5) years from the date of grant or such
shorter term as may be provided in the Notice of Grant.

        9. Option Exercise Price and Consideration.

           (a) Exercise Price. The per share exercise price for the Shares to be
issued pursuant to exercise of an Option shall be determined by the
Administrator, subject to the following:

               (i) In the case of an Incentive Stock Option

                   (A) granted to an Employee who, at the time the Incentive
Stock Option is granted, owns stock representing more than ten percent (10%) of
the voting power of all classes of stock of the Company or any Parent or
Subsidiary, the per Share exercise price shall be no less than 110% of the Fair
Market Value per Share on the date of grant.

                   (B) granted to any Employee other than an Employee described
in paragraph (A) immediately above, the per Share exercise price shall be no
less than 100% of the Fair Market Value per Share on the date of grant.

               (ii) In the case of a Nonstatutory Stock Option, the per Share
exercise price shall be determined by the Administrator, but shall in no event
be less than the par value per Share.

           (b) Waiting Period and Exercise Dates. At the time an Option is
granted, the Administrator shall fix the period within which the Option may be
exercised and shall determine any conditions which must be satisfied before the
Option may be exercised. In so doing, the Administrator may specify that an
Option may not be exercised until the completion of a service period.

           (c) Form of Consideration. The Administrator shall determine the
acceptable form of consideration for exercising an Option, including the method
of payment. In the case of an Incentive Stock Option, the Administrator shall
determine the acceptable form of consideration at the time of grant. Such
consideration may consist entirely of:

               (i) cash;

               (ii) check;

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               (iii) money order;

               (iv) promissory note;

               (v) other Shares which (A) in the case of Shares acquired upon
exercise of an option, have been owned by the Optionee for more than six (6)
months on the date of surrender, and (B) have a Fair Market Value on the date of
surrender equal to the aggregate exercise price of the Shares as to which said
Option shall be exercised;

               (vi) delivery of a properly executed exercise notice together
with such other documentation as the Administrator and the broker, if
applicable, shall require to effect an exercise of the Option and delivery to
the Company of the sale or loan proceeds required to pay the exercise price;

               (vii) a reduction in the amount of any Company liability to the
Optionee, including any liability attributable to the Optionee's participation
in any Company-sponsored deferred compensation program or arrangement;

               (viii) any combination of the foregoing methods of payment; or

               (ix) such other consideration and method of payment for the
issuance of Shares to the extent permitted by Applicable Laws.

        10. Exercise of Option.

            (a) Procedure for Exercise: Rights as a Stockholder. Any Option
granted hereunder shall be exercisable according to the terms of the Plan and at
such times and under such conditions as determined by the Administrator and set
forth in the Option Agreement.

                  An Option may not be exercised for a fraction of a Share.

                  An Option shall be deemed exercised when the Company receives:
(i) written notice of exercise (in accordance with the Option Agreement) from
the person entitled to exercise the Option, and (ii) full payment for the Shares
with respect to which the Option is exercised. Full payment may consist of any
consideration and method of payment authorized by the Administrator and
permitted by the Option Agreement and the Plan. Shares issued upon exercise of
an Option shall be issued in the name of the Optionee or, if requested by the
Optionee, in the name of the Optionee and his or her spouse. Until the stock
certificate evidencing such Shares is issued (as evidenced by the appropriate
entry on the books of the Company or of a duly authorized transfer agent of the
Company), no right to vote or receive dividends or any other rights as a
shareholder shall exist with respect to the Optioned Stock, notwithstanding the
exercise of the Option. The Company shall issue (or cause to be issued) such
stock certificate promptly after the Option is exercised. No adjustment will be
made for a dividend or other right for which the record date is prior to the
date the stock certificate is issued, except as provided in Section 16 of the
Plan.

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                  Exercising an Option in any manner shall decrease the number
of Shares thereafter available, both for purposes of the Plan and for sale under
the Option, by the number of Shares as to which the Option is exercised.

           (b) Termination of Employment, Directorship or Consulting
Relationship. Upon termination of an Optionee's Continuous Status as an
Employee, Director or Consultant (but not in the event of a change of status
from Employee to Consultant (in which case an Employee's Incentive Stock Option
shall automatically convert to a Nonstatutory Stock Option on the ninety-first
(91st) day following such change of status) or from Consultant to Employee),
other than upon the Optionee's death or Disability, the Optionee may exercise
his or her Option, but only within such period of time as is specified in the
Notice of Grant, and only to the extent that the Optionee was entitled to
exercise it at the date of termination (but in no event later than the
expiration of the term of such Option as set forth in the Notice of Grant). In
the absence of a specified time in the Notice of Grant, the Option shall remain
exercisable for thirty (30) days following the Optionee's termination of
Continuous Status as an Employee, Director or Consultant. In the case of an
Incentive Stock Option, such period of time shall not exceed ninety (90) days
from the date of termination. If, at the date of termination, the Optionee is
not entitled to exercise his or her entire Option, the Shares covered by the
unexercisable portion of the Option shall revert to the Plan. If, after
termination, the Optionee does not exercise his or her Option within the time
specified, the Option shall terminate, and the Shares covered by such Option
shall revert to the Plan.

           (c) Disability of Optionee. Notwithstanding the provisions of Section
10(b) above, in the event of termination of an Optionee's Consulting
relationship or Continuous Status as an Employee or Director as a result of his
Disability then the period during which each outstanding option held by the
Optionee is to remain exercisable shall be limited to the six (6)-month period
following the date of such cessation of service. However, should such Disability
be deemed to constitute Permanent Disability, then the period during which each
outstanding option held by the Optionee is to remain exercisable shall be
extended by an additional six (6) months so that the exercise period shall be
limited to the twelve (12)-month period following the date of the Optionee's
cessation of Service by reason of such Permanent Disability. For the purposes of
the Plan, Disability shall be determined by the Administrator on the basis of
such medical evidence as the Administrator deems warranted under the
circumstances. For purposes of the Plan, Disability shall be deemed to
constitute Permanent Disability in the event that such Disability is expected to
result in death or has lasted or can be expected to last for a continuous period
of not less than twelve (12) months.

           (d) Death of Optionee. In the event of the death of an Optionee, the
Option may be exercised at any time within twelve (12) months (or such other
period of time as is determined by the Administrator, with such determination in
the case of an Incentive Stock Option being made at the time of grant of the
Option) following the date of death (but in no event later than the expiration
of the term of such Option as set forth in the Notice of Grant), by the
Optionee's estate or by a person who acquired the right to exercise the Option
by bequest or inheritance, but only to the extent that the Optionee was entitled
to exercise the Option at the date of death. If, at the time of death, the
Optionee was not entitled to exercise his or her entire Option, the Shares
covered by the unexercisable portion of the Option shall immediately revert to
the Plan. If, after death, the Optionee's estate or a person who acquired the
right to exercise

<PAGE>   11

the Option by bequest or inheritance does not exercise the Option within the
time specified herein, the Option shall terminate, and the Shares covered by
such Option shall revert to the Plan.

           (e) Rule 16b-3. Options granted to individuals subject to Section 16
of the Exchange Act ("Insiders") must comply with the applicable provisions of
Rule 16b-3 and shall contain such additional conditions or restrictions as may
be required thereunder to qualify for the maximum exemption from Section 16 of
the Exchange Act with respect to Plan transactions.

           (f) Buyout Provisions. The Administrator may at any time offer to buy
out for a payment in cash or Shares, an Option previously granted, based on such
terms and conditions as the Administrator shall establish and communicate to the
Optionee at the time that such offer is made.

        11. Granting of Options to Independent Directors. During the term of the
Plan, a person who is an Independent Director as of the Public Trading Date (an
"IPO Independent Director") and has not previously received an Option grant
automatically shall be granted an Option to purchase 24,000 shares of Common
Stock on the date of such consummation (an "IPO Option"). IPO Independent
Directors and a person who becomes an Independent Director after the Public
Trading Date automatically shall be granted an Option to purchase 8000 shares of
Common Stock (subject to adjustment as provided in Section 16) on the date of
each annual meeting of stockholders after the Public Trading Date (a "Post-IPO
Option"). Members of the Board who are employees of the Company who subsequently
retire from the Company and remain on the Board will not receive an IPO Option
grant, but to the extent they are otherwise eligible, will receive, after
retirement from employment with the Company, Post-IPO Options. All the foregoing
Option grants authorized by this Section 11 are subject to stockholder approval
of the Plan.

        12. Terms of Options Granted to Independent Directors. The per Share
price of each Option granted to an Independent Director shall equal 100% of the
Fair Market Value of a share of Common Stock on the date the Option is granted;
provided, however, that the per Share price of each Option granted to an
Independent Director on the date of the initial public offering of Common Stock
shall equal the initial public offering price per Share (as determined by the
Pricing Committee of the Board in its sole and absolute discretion. IPO Options
(as defined in Section 11) granted to Independent Directors shall become
exercisable in cumulative quarterly installments of 1/12 of the Shares subject
to such option on each of the quarterly anniversaries of the date of IPO Option
grant, commencing with the first such quarterly anniversary, such that each IPO
Option shall be one hundred percent (100%) vested on the third anniversary of
its date of grant. Post-IPO Options (as defined in Section 11) granted to
Independent Directors shall become vested in cumulative quarterly installments
of 1/4 of the Shares subject to such Option on each of the quarterly
anniversaries of the date of Post-IPO Option grant, commencing with the ninth
quarterly anniversary of such date of Post-IPO Option grant, such that each
Post-IPO Option shall be one hundred percent (100%) vested on the third
anniversary of the date of Post-IPO Option grant. Subject to Section 10, the
term of each Option granted to an Independent Director shall be ten (10) years
from the date the Option is granted. No portion of an Option which is
unexercisable at the time of an Independent Director's termination of membership
on the Board shall thereafter become exercisable.

<PAGE>   12

        13. Stock Purchase Rights.

            (a) Rights to Purchase. Stock Purchase Rights may be issued either
alone, in addition to, or in tandem with other awards granted under the Plan.
After the Administrator determines that it will offer Stock Purchase Rights
under the Plan, it shall advise the offeree in writing, by means of a Notice of
Grant, of the terms, conditions and restrictions related to the offer, including
the number of Shares that the offeree shall be entitled to purchase, the price
to be paid, and the time within which the offeree must accept such offer, which
shall in no event exceed thirty (30) days from the date upon which the
Administrator made the determination to grant the Stock Purchase Right. The
offer shall be accepted by execution of a Restricted Stock Purchase Agreement in
the form determined by the Administrator.

            (b) Repurchase Option. Unless the Administrator determines
otherwise, the Restricted Stock Purchase Agreement shall grant the Company a
repurchase option exercisable upon the voluntary or involuntary termination of
the purchaser's Continuous Status as an Employee, Director or Consultant with
the Company for any reason (including death or Disability). The purchase price
for Shares repurchased pursuant to the Restricted Stock purchase agreement shall
be the original price paid by the purchaser and may be paid by cancellation of
any indebtedness of the purchaser to the Company. The repurchase option shall
lapse at a rate determined by the Administrator.

            (c) Rule 16b-3. Stock Purchase Rights granted to Insiders, and
Shares purchased by Insiders in connection with Stock Purchase Rights, shall be
subject to any restrictions applicable thereto in compliance with Rule 16b-3. An
Insider may only purchase Shares pursuant to the grant of a Stock Purchase
Right, and may only sell Shares purchased pursuant to the grant of a Stock
Purchase Right, during such time or times as are permitted by Rule 16b-3.

            (d) Other Provisions. The Restricted Stock Purchase Agreement shall
contain such other terms, provisions and conditions not inconsistent with the
Plan as may be determined by the Administrator in its sole discretion including
but not limited to the per Share purchase price, which shall in no event be less
than the par value per Share. In addition, the provisions of Restricted Stock
Purchase Agreements need not be the same with respect to each purchaser.

            (e) Rights as a Stockholder. Once the Stock Purchase Right is
exercised, the purchaser shall have the rights equivalent to those of a
shareholder, and shall be a shareholder when his or her purchase is entered upon
the records of the duly authorized transfer agent of the Company. No adjustment
will be made for a dividend or other right for which the record date is prior to
the date the Stock Purchase Right is exercised, except as provided in Section 16
of the Plan.

        14. Stock Withholding to Satisfy Withholding Tax Obligations. At the
discretion of the Administrator, Optionees may satisfy withholding obligations
as provided in this paragraph. When an Optionee incurs tax liability in
connection with an Option or Stock Purchase Right, which tax liability is
subject to tax withholding under applicable tax laws, and the Optionee is
obligated to pay the Company an amount required to be withheld under applicable
tax laws, the Optionee may satisfy the withholding tax obligation by electing to
have the Company withhold

<PAGE>   13

from the Shares to be issued in connection with the Stock Purchase Right, if
any, that number of Shares having a Fair Market Value equal to the amount
required to be withheld. The Fair Market Value of the Shares to be withheld
shall be determined on the date that the amount of tax to be withheld is to be
determined (the "Tax Date").

        All elections by an Optionee to have Shares withheld for this purpose
shall be made in writing in a form acceptable to the Administrator and shall be
subject to the following restrictions:

           (a) the election must be made on or prior to the applicable Tax Date;

           (b) once made, the election shall be irrevocable as to the particular
Shares of the Option or Right as to which the election is made;

           (c) all elections shall be subject to the consent or disapproval of
the Administrator;

           (d) if the Optionee is subject to Rule 16b-3, the election must
comply with the applicable provisions of Rule 16b-3 and shall be subject to such
additional conditions or restrictions as may be required thereunder to qualify
for the maximum exemption from Section 16 of the Exchange Act with respect to
Plan transactions.

        In the event the election to have Shares withheld is made by an Optionee
and the Tax Date is deferred under Section 83 of the Code because no election is
filed under Section 83(b) of the Code, the Optionee shall receive the full
number of Shares with respect to which the Option or Stock Purchase Right is
exercised but such Optionee shall be unconditionally obligated to tender back to
the Company the proper number of Shares on the Tax Date.

        15. Non-Transferability of Options and Stock Purchase Rights. An Option
or Stock Purchase Right may not be sold, pledged, assigned, hypothecated,
transferred, or disposed of in any manner other than by will or by the laws of
descent or distribution and may be exercised, during the lifetime of the
Optionee, only by the Optionee.

        16. Adjustments Upon Changes in Capitalization, Dissolution, Merger or
Asset Sale.

            (a) Changes in Capitalization. Subject to any required action by the
shareholders of the Company, the number of shares of Common Stock covered by
each outstanding Option and Stock Purchase Right, and the number of shares of
Common Stock which have been authorized for issuance under the Plan but as to
which no Options or Stock Purchase Rights have yet been granted or which have
been returned to the Plan upon cancellation or expiration of an Option or Stock
Purchase Right, as well as the price per share of Common Stock covered by each
such outstanding Option or Stock Purchase Right, shall be proportionately
adjusted for any increase or decrease in the number of issued shares of Common
Stock resulting from a stock split, reverse stock split, stock dividend,
combination or reclassification of the Common Stock, or any other increase or
decrease in the number of issued shares of Common Stock effected without receipt
of consideration by the Company; provided, however, that conversion of any
convertible securities of the Company shall not be deemed to have been effected
without receipt of consideration. Such adjustment shall be made by the Board,
whose

<PAGE>   14

determination in that respect shall be final, binding and conclusive. Except as
expressly provided herein, no issuance by the Company of shares of stock of any
class, or securities convertible into shares of stock of any class, shall
affect, and no adjustment by reason thereof shall be made with respect to, the
number or price of shares of Common Stock subject to an Option or Stock Purchase
Right.

            (b) Dissolution or Liquidation. In the event of the proposed
dissolution or liquidation of the Company, the Board shall notify the Optionee
at least fifteen (15) days prior to such proposed action. To the extent it has
not been previously exercised, the Option or Stock Purchase Right will terminate
immediately prior to the consummation of such proposed action.

            (c) Merger or Asset Sale. In the event of a merger of the Company
with or into another corporation, or the sale of substantially all of the assets
of the Company, each outstanding Option and Stock Purchase Right may be assumed
or an equivalent option or right may be substituted by the successor corporation
or a Parent or Subsidiary of the successor corporation. The Administrator may,
in lieu of such assumption or substitution, provide for the Optionee to have the
right to exercise the Option or Stock Purchase Right as to all or a portion of
the Optioned Stock, including Shares as to which it would not otherwise be
exercisable. If the Administrator makes an Option or Stock Purchase Right
exercisable in lieu of assumption or substitution in the event of a merger or
sale of assets, the Administrator shall notify the Optionee that the Option or
Stock Purchase Right shall be fully exercisable for a period of fifteen (15)
days from the date of such notice, and the Option or Stock Purchase Right will
terminate upon the expiration of such period. For the purposes of this
paragraph, the Option or Stock Purchase Right shall be considered assumed if,
following the merger or sale of assets, the option or right confers the right to
purchase, for each Share of Optioned Stock subject to the Option or Stock
Purchase Right immediately prior to the merger or sale of assets, the
consideration (whether stock, cash, or other securities or property) received in
the merger or sale of assets by holders of Common Stock for each Share held on
the effective date of the transaction (and if holders were offered a choice of
consideration, the type of consideration chosen by the holders of a majority of
the outstanding Shares); provided, however, that if such consideration received
in the merger or sale of assets was not solely common stock of the successor
corporation or its Parent, the Administrator may, with the consent of the
successor corporation, provide for the consideration to be received upon the
exercise of the Option or Stock Purchase Right, for each Share of Optioned Stock
subject to the Option or Stock Purchase Right, to be solely common stock of the
successor corporation or its Parent equal in fair market value to the per share
consideration received by holders of Common Stock in the merger or sale of
assets.

        17. Date of Grant. The date of grant of an Option or Stock Purchase
Right shall be, for all purposes, the date on which the Administrator makes the
determination granting such Option or Stock Purchase Right, or such other later
date as is determined by the Administrator. Notice of the determination shall be
provided to each Optionee within a reasonable time after the date of such grant.

        18. Amendment and Termination of the Plan.

            (a) Amendment and Termination. The Board may at any time amend,
alter, suspend or terminate the Plan.

<PAGE>   15

            (b) Stockholder Approval. The Company shall obtain shareholder
approval of any Plan amendment to the extent necessary and desirable to comply
with Rule 16b-3 or with Section 422 of the Code (or any successor rule or
statute or other applicable law, rule or regulation, including the requirements
of any exchange or quotation system on which the Common Stock is listed or
quoted). Such shareholder approval, if required, shall be obtained in such a
manner and to such a degree as is required by the applicable law, rule or
regulation.

            (c) Effect of Amendment or Termination. No amendment, alteration,
suspension or termination of the Plan shall impair the rights of any Optionee,
unless mutually agreed otherwise between the Optionee and the Administrator,
which agreement must be in writing and signed by the Optionee and the Company.

        19. Conditions Upon Issuance of Shares.

            (a) Legal Compliance. Shares shall not be issued pursuant to the
exercise of an Option or Stock Purchase Right unless the exercise of such Option
or Stock Purchase Right and the issuance and delivery of such Shares shall
comply with all relevant provisions of law, including, without limitation, the
Securities Act of 1933, as amended, the Exchange Act, the rules and regulations
promulgated thereunder, and Applicable Laws, and shall be further subject to the
approval of counsel for the Company with respect to such compliance.

            (b) Investment Representations. As a condition to the exercise of an
Option or Stock Purchase Right, the Company may require the person exercising
such Option or Stock Purchase Right to represent and warrant at the time of any
such exercise that the Shares are being purchased only for investment and
without any present intention to sell or distribute such Shares if, in the
opinion of counsel for the Company, such a representation is required.

        20. Liability of Company.

            (a) Inability to Obtain Authority. The inability of the Company to
obtain authority from any regulatory body having jurisdiction, which authority
is deemed by the Company's counsel to be necessary to the lawful issuance and
sale of any Shares hereunder, shall relieve the Company of any liability in
respect of the failure to issue or sell such Shares as to which such requisite
authority shall not have been obtained.

            (b) Grants Exceeding Allotted Shares. If the Optioned Stock covered
by an Option or Stock Purchase Right exceeds, as of the date of grant, the
number of Shares which may be issued under the Plan without additional
shareholder approval, such Option or Stock Purchase Right shall be void with
respect to such excess Optioned Stock, unless shareholder approval of an
amendment sufficiently increasing the number of Shares subject to the Plan is
timely obtained in accordance with Section 18(b) of the Plan.

        21. Reservation of Shares. The Company, during the term of this Plan,
will at all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan.

        22. Stockholder Approval. Continuance of the Plan shall be subject to
approval by the shareholders of the Company within twelve (12) months before or
after the date the Plan is

<PAGE>   16

adopted. Such shareholder approval shall be obtained in the manner and to the
degree required under applicable federal and state law.

        23. Governing Law. The validity and enforceability of this Plan shall be
governed by and construed in accordance with the laws of the State of Delaware
without regard to otherwise governing principles of conflicts of law.<PAGE>   1

                                                                   EXHIBIT 10.16

                            ACLARA BIOSCIENCES, INC.

                          EMPLOYEE STOCK PURCHASE PLAN

<PAGE>   2

                            ACLARA BIOSCIENCES, INC.

                          EMPLOYEE STOCK PURCHASE PLAN

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                           PAGE
                                                                                           ----
<S>     <C>                                                                                 <C>
1.      Definitions..........................................................................1
2.      Stock Subject to the Plan............................................................3
3.      Grant of Options.....................................................................3
4.      Exercise of Options; Option Price....................................................5
5.      Withdrawal from the Plan.............................................................6
6.      Termination of Employment............................................................7
7.      Restriction upon Assignment..........................................................7
8.      No Rights of Stockholders until Shares Issued........................................7
9.      Changes in the Stock and Corporate Events; Adjustment of Options.....................8
10.     Use of Funds; No Interest Paid.......................................................9
11.     Dividends............................................................................9
12.     Amendment, Suspension or Termination of the Plan....................................10
13.     Administration by Committee; Rules and Regulations..................................10
14.     Designation of Subsidiary Corporations..............................................11
15.     No Rights as an Employee............................................................11
16.     Term; Approval by Stockholders......................................................11
17.     Effect upon Other Plans.............................................................11
18.     Conditions to Issuance of Stock Certificates........................................12
19.     Notification of Disposition.........................................................12
20.     Notices.............................................................................12
21.     Headings............................................................................13
</TABLE>

                                       i

<PAGE>   3

                            ACLARA BIOSCIENCES, INC.

                          EMPLOYEE STOCK PURCHASE PLAN

        ACLARA BioSciences, Inc., a Delaware corporation (the "Company"), hereby
adopts the ACLARA BioSciences, Inc. Employee Stock Purchase Plan (the "Plan"),
effective as of _____________, 2000.

        The purposes of the Plan are as follows:

                (1) To assist eligible employees of the Company and its
        Designated Subsidiary Corporations (as defined below) in acquiring stock
        ownership in the Company pursuant to a plan which is intended to qualify
        as an "employee stock purchase plan", within the meaning of Section
        423(b) of the Code (as defined below).

                (2) To help such employees provide for their future security and
        to encourage them to remain in the employment of the Company and its
        Subsidiary Corporations.

        1. DEFINITIONS. Whenever any of the following terms is used in the Plan
with the first letter or letters capitalized, it shall have the following
meaning unless context clearly indicates to the contrary (such definitions to be
equally applicable to both the singular and the plural forms of the terms
defined):

           (a) "Account" shall mean the account established for an Eligible
Employee under the Plan with respect to an Offering Period.

           (b) "Agent" shall mean the brokerage firm, bank or other financial
institution, entity or person(s) engaged, retained, appointed or authorized to
act as the agent of the Company or an Employee with regard to the Plan.

           (c) "Authorization" shall mean an Eligible Employee's payroll
deduction authorization with respect to an Offering Period provided by such
Eligible Employee in accordance with Section 3(b).

           (d) "Base Compensation" of an Eligible Employee shall mean the gross
base compensation received by such Eligible Employee on each Payday as
compensation for services to the Company or any Designated Subsidiary
Corporation, excluding overtime payments, sales commissions, incentive
compensation, bonuses, expense reimbursements, fringe benefits and other
special-payments.

           (e) "Board" means the Board of Directors of the Company.

           (f) "Code" means the Internal Revenue Code of 1986, as amended.

           (g) "Committee" means the committee of the Board appointed to
administer the Plan pursuant to Section 13.

<PAGE>   4

           (h) "Company" means ACLARA BioSciences, Inc., a Delaware corporation.

           (i) "Date of Exercise" of any Option means the date on which such
Option is exercised, which shall be the last day of the Offering Period with
respect to which the Option was granted, in accordance with Section 4(a) (except
as provided in Section 9).

           (j) "Date of Grant" of any Option means the date on which such Option
is granted, which shall be the first day of the Offering Period with respect to
which the Option was granted, in accordance with Section 3(a).

           (k) "Designated Subsidiary Corporation" means any Subsidiary
Corporation designated by the Board in accordance with Section 14.

           (l) "Effective Date" means the first day of the first Offering
Period, which shall be the date immediately preceding the first date on which a
share of Stock is traded on an exchange or quoted on Nasdaq or a successor
quotation system.

           (m) "Eligible Employee" means an Employee of the Company or any
Designated Subsidiary Corporation: (i) who does not, immediately after the
Option is granted, own (directly or through attribution) stock possessing five
percent (5%) or more of the total combined voting power or value of all classes
of Stock or other stock of the Company, a Parent Corporation or a Subsidiary
Corporation (as determined under Section 423(b)(3) of the Code); (ii) whose
customary employment is for more than twenty (20) hours per week; (iii) whose
customary employment is for more than five (5) months in any calendar year; and
(iv) who has been employed by the Company, any Parent Corporation and any
Subsidiary Corporation for not less than six (6) months. For purposes of
paragraph (i) above, the rules of Section 424(d) of the Code with regard to the
attribution of stock ownership shall apply in determining the stock ownership of
an individual, and stock which an Employee may purchase under outstanding
options shall be treated as stock owned by the Employee. During a leave of
absence meeting the requirements of Treasury Regulation Section 1.421-7(h)(2),
an individual shall be treated as an Employee of the Company or Subsidiary
Corporation employing such individual immediately prior to such leave.

           (n) "Employee" shall mean an individual who renders services to the
Company or a Subsidiary Corporation in the status of an "employee", within the
meaning of Code Section 3401(c). "Employee" shall not include any director of
the Company or a Subsidiary Corporation who does not render services to the
Company or a Subsidiary Corporation in the status of an "employee", within the
meaning of Code Section 3401(c).

           (o) "Offering Period" shall mean each six-month period commencing on
any November 1 and May 1 on or after the Effective Date; provided, however, that
the first Offering Period under the Plan shall be the period commencing on the
Effective Date and ending October 31, 2000. Options shall be granted on the Date
of Grant and exercised on the Date of Exercise, as provided in Sections 3(a) and
4(a), respectively.

                                       2
<PAGE>   5

           (p) "Option" means an option to purchase shares of Stock granted
under the Plan to an Eligible Employee in accordance with Section 3(a).

           (q) "Option Price" means the option price per share of Stock
determined in accordance with Section 4(b).

           (r) "Parent Corporation" means any corporation, other than the
Company, in an unbroken chain of corporations ending with the Company if, at the
time of the granting of the Option, each of the corporations other than the
Company owns stock possessing 50% or more of the total combined voting power of
all classes of stock in one of the other corporations in such chain.

           (s) "Payday" means the regular and recurring established day for
payment of Base Compensation to an Employee of the Company or any Subsidiary
Corporation.

           (t) "Plan" means the ACLARA BioSciences, Inc. Employee Stock Purchase
Plan.

           (u) "Stock" means the shares of the Company's Common Stock, $.001 par
value.

           (v) "Subsidiary Corporation" means any corporation, other than the
Company, in an unbroken chain of corporations beginning with the Company if, at
the time of the granting of the Option, each of the corporations other than the
last corporation in an unbroken chain owns stock possessing 50% or more of the
total combined voting power of all classes of stock in one of the other
corporations in such chain.

        2. STOCK SUBJECT TO THE PLAN. Subject to the provisions of Section 9
hereof (relating to adjustments upon changes in the Stock) and Section 12 hereof
(relating to amendments of the Plan), the Stock that may be sold pursuant to
Options granted under the Plan shall not exceed in the aggregate three hundred
thousand (300,000) shares of Stock. The shares of Stock sold pursuant to Options
granted under the Plan may be unissued shares or treasury shares of Stock, or
shares of Stock bought on the New York Stock Exchange or other
nationally-recognized exchange, or other market, for purposes of the Plan.

        3. GRANT OF OPTIONS.

           (a) Option Grants. The Company shall grant Options under the Plan to
all Eligible Employees in successive Offering Periods until the earlier of: (i)
the date on which the number of shares of Stock available under the Plan have
been sold, or (ii) the date on which the Plan is suspended or terminates. Each
Employee who is an Eligible Employee on the first day of an Offering Period
shall be granted an Option with respect to such Offering Period. The Date of
Grant of such an Option shall be the first day of the Offering Period with
respect to which such Option was granted. Each Option shall expire on the Date
of Exercise immediately after the automatic exercise of the Option in accordance
with Section 4(a), unless such Option terminates earlier in accordance with
Section 5, 6 or 9. The number of shares of Stock subject to an Eligible

                                       3
<PAGE>   6
Employee's Option shall equal the cumulative payroll deductions authorized by
such Eligible Employee in accordance with subsection (b) for the Option Period
(if any), divided by the Option Price; provided, however, that the number of
shares of Stock subject to such Option shall not exceed five thousand (5,000)
shares; and, provided, further, that the number of shares of Stock subject to
such Option shall not exceed the number determined in accordance with subsection
(c). The Company shall not grant an Option with respect to an Offering Period to
any individual who is not an Eligible Employee on the first day of such Offering
Period.

           (b) Election to Participate; Payroll Deduction Authorization. Except
as provided in subsection (d), an Eligible Employee shall participate in the
Plan only by means of payroll deduction. Each Eligible Employee who elects to
participate in the Plan with respect to an Offering Period shall deliver to the
Company, not later than ten (10) days before the first day of the Offering
Period (or such shorter period as determined by the Committee in its
discretion), a completed and executed written payroll deduction authorization in
a form prepared by the Committee (the "Authorization"). An Eligible Employee's
Authorization shall give notice of such Eligible Employee's election to
participate in the Plan for the next following Offering Period (and subsequent
Offering Periods) and shall designate a whole percentage of such Eligible
Employee's Base Compensation to be withheld by the Company or the Designated
Subsidiary Corporation employing such Eligible Employee on each Payday during
the Offering Period. An Eligible Employee may designate any whole percentage of
Base Compensation which is not be less than one percent (1%) and not more than
fifteen percent (15%). An Eligible Employee's Base Compensation payable during
an Offering Period shall be reduced each Payday through payroll deduction in an
amount equal to the percentage specified in the Authorization, and such amount
shall be credited to such Eligible Employee's Account under the Plan.
Notwithstanding the preceding sentence, at the Committee's discretion payroll
deductions with respect to the Initial Offering Period under the Plan may
commence as of the second Payday following the Effective Date and not the
initial Payday following the Effective Date. An Eligible Employee may change the
percentage of Base Compensation designated in the Authorization, subject to the
limits of this subsection (b), or may suspend the Authorization, at any time
during the Offering Period, provided, that any such change or suspension shall
become effective not later than ten (10) days after receipt by the Company. Any
Authorization shall remain in effect for each subsequent Offering Period, unless
the Eligible Employee submits a new Authorization pursuant to this subsection
(b), withdraws from the Plan pursuant to Section 5, ceases to be an Eligible
Employee as defined in Section 1(m) or terminates employment as provided in
Section 6.

           (c) $25,000 Limitation. No Eligible Employee shall be granted an
Option under the Plan which permits his rights to purchase shares of Stock under
the Plan, together with other options to purchase shares of Stock or other stock
under all other employee stock purchase plans of the Company, any Parent
Corporation or any Subsidiary Corporation subject to the Section 423, to accrue
at a rate which exceeds $25,000 of fair market value of such shares of Stock or
other stock (determined at the time the Option or other option is granted) for
each calendar year in which the Option is outstanding at any time. For purpose
of the limitation imposed by this subsection, (i) the right to purchase shares
of Stock or other stock under an Option or other option accrues when the Option
or other option (or any portion thereof) first becomes exercisable during the
calendar year, (ii) the right to purchase shares of Stock or other stock under
an Option or other option accrues at the rate provided in the Option or other
option, but in no case may such rate exceed $25,000 of the fair market value of
such Stock or other stock (determined at the time such Option or other option is
granted) for any one calendar year, and

                                       4
<PAGE>   7

(iii) a right to purchase Stock or other stock which has accrued under an Option
or other option may not be carried over to any Option or other option. This
limitation shall be applied in accordance with Section 423(b)(8) of the Code and
the Treasury Regulations thereunder.

           (d) Leaves of Absence. During a leave of absence meeting the
requirements of Treasury Regulation Section 1.421-7(h)(2), an Employee may
continue to participate in the Plan by making cash payments to the Company on
each Payday equal to the amount of the Employee's payroll deduction under the
Plan for the Payday immediately preceding the first day of such Employee's leave
of absence.

        4. EXERCISE OF OPTIONS; OPTION PRICE.

           (a) Option Exercise. Each Employee automatically and without any act
on such Employee's part shall be deemed to have exercised such Employee's Option
on the Date of Exercise to the extent that the balance then in the Employee's
Account is sufficient to purchase, at the Option Price, shares of the Stock
subject to the Option (including fractional shares).

           (b) Option Price Defined. The option price per share of Stock (the
"Option Price") to be paid by an Employee upon the exercise of the Employee's
Option shall be equal to 85% of the lesser of: (i) the Fair Market Value of a
share of Stock on the Date of Exercise and (ii) the Fair Market Value of a share
of Stock on the Date of Grant. The Fair Market Value of a share of Stock as of a
given date shall be: (A) the closing price of a share of Stock on the principal
exchange on which the Stock is then trading, if any, on such date (or, if shares
of Stock were not traded on such date, then on the next preceding trading day
during which a sale occurred); (B) if the Stock is not traded on an exchange,
but is quoted on Nasdaq or a successor quotation system, (I) the last sales
price (if the Stock is then listed as a National Market Issue under the NASD
National Market System), or (II) the mean between the closing representative bid
and asked prices (in all other cases) for a share of Stock on such date (or, if
shares of Stock were not traded on such date, then on the next preceding trading
day during which a sale occurred) as reported by Nasdaq or such successor
quotation system; (iii) if the Stock is not publicly traded on an exchange and
not quoted on Nasdaq or a successor quotation system, the mean between the
closing bid and asked prices for a share of Stock on such date (or, if shares of
Stock were not traded on such date, then on the next preceding trading day
during which a sale occurred), as determined in good faith by the Committee; or
(iv) if the Stock is not publicly traded, the fair market value of a share of
Stock established by the Committee acting in good faith.

           (c) Book Entry/Share Certificates. As soon as practicable after the
purchase of shares of Stock upon the exercise of an Option by an Employee, the
Company shall issue the shares of Stock to such Employee and such shares shall
be held in the custody of the Agent for the benefit of the Employee. The Company
or the Agent shall make an entry on its books and records indicating that the
shares of Stock purchased in connection with such exercise (including any
partial share) have been duly issued as of that date to such Employee. An
Employee shall have the right at any time to request in writing a certificate or
certificates for all or a portion of the whole shares of Stock purchased
hereunder. Upon receipt of an Employee's written request

                                       5
<PAGE>   8

for any such certificate, the Company shall (or shall cause the Agent to),
within ten (10) days after the date of such receipt, deliver any such
certificate to the Employee; provided, however, that no certificate shall be
issued to an Employee with respect to Stock purchased hereunder until the
expiration of eighteen (18) months from the date of exercise of the Option to
purchase such Stock. Nothing in this subsection (c) shall prohibit the sale or
other disposition by an Employee of shares of Stock purchased hereunder. In the
event the Company is required to obtain authority from any commission or agency
to issue any certificate or certificates for all or a portion of the whole
shares of Stock purchased hereunder, the Company shall seek to obtain such
authority as soon as reasonably practicable.

           (d) Pro Rata Allocations. If the total number of shares of Stock for
which Options are to be exercised on any date exceeds the number of shares of
Stock remaining unsold under the Plan (after deduction for all shares of Stock
for which Options have theretofore been exercised), the Committee shall make a
pro rata allocation of the available remaining shares of Stock in as nearly a
uniform manner as shall be practicable and the balance of the amount credited to
the Account of each Employee which has not been applied to the purchase of
shares of Stock shall be paid to such Employee in one lump sum in cash within
thirty (30) days after the Date of Exercise, without any interest thereon.

           (e) Information Statement. The Company shall provide each Employee
whose Option is exercised with an information statement in accordance with
Section 6039(a) of the Code and the Treasury Regulations thereunder. The Company
shall maintain a procedure for identifying certificates of shares of Stock sold
upon the exercise of Options in accordance with Section 6039(b) of the Code.

        5. WITHDRAWAL FROM THE PLAN.

           (a) Withdrawal Election. An Employee may withdraw from participation
under the Plan at any time, except that an Employee may not withdraw during the
last ten (10) days of any Option Period. An Employee electing to withdraw from
the Plan must deliver to the Company a notice of withdrawal in a form prepared
by the Committee (the "Withdrawal Election"), not later than ten (10) days prior
to the Date of Exercise for such Option Period. Upon receipt of an Employee's
Withdrawal Election, the Company or Subsidiary Corporation employing the
Employee shall pay to the Employee the amount credited to the Employee's Account
in one lump sum payment in cash, without any interest thereon, and subject to
Section 4(c), the Company shall (or shall cause the Agent to) deliver to the
Employee certificates for any whole shares of Stock previously purchased by the
Employee (the value of any fractional share to be returned to such Employee by
check), in either case within thirty (30) days of receipt of the Employee's
Withdrawal Election. Upon receipt of an Employee's Withdrawal Election by the
Company, the Employee shall cease to participate in the Plan and the Employee's
Option for such Option Period shall terminate.

           (b) Eligibility following Withdrawal. An Employee who withdraws from
the Plan with respect to an Option Period, and who is still an Eligible
Employee, may elect to

                                       6
<PAGE>   9

participate again in the Plan for any subsequent Offering Period by delivering
to the Company an Authorization pursuant to Section 3(b).

        6. TERMINATION OF EMPLOYMENT.

           (a) Termination of Employment Other than by Death. If the employment
of an Employee with the Company and the Subsidiary Corporation terminates other
than by death, the Employee's participation in the Plan automatically and
without any act on the Employee's part shall terminate as of the date of the
termination of the Employee's employment. As soon as practicable after such a
termination of employment, the Company or Subsidiary Corporation employing the
Employee shall pay to the Employee the amount credited to the Employee's Account
in one lump sum payment in cash, without any interest thereon, and subject to
Section 4(c), the Company shall (or shall cause the Agent to) deliver to the
Employee certificates for any whole shares of Stock previously purchased by the
Employee (the value of any fractional share to be returned to such Employee by
check). Upon an Employee's termination of employment covered by this subsection,
the Employee's Authorization and Option under the Plan shall terminate.

           (b) Termination by Death. If the employment of an Employee is
terminated by the Employee's death, the executor of the Employee's will or the
administrator of the Employee's estate, by written notice to the Company, may
request payment of the balance in the Employee's Account, in which event the
Company or Subsidiary Corporation employing the Employee shall pay the amount
credited to the Employee's Account in one lump sum payment in cash, without any
interest thereon, and subject to Section 4(c), the Company shall (or shall cause
the Agent to) deliver to the Employee certificates for any whole shares of Stock
previously purchased by the Employee (the value of any fractional share to be
returned to such Employee by check) as soon as practicable after receiving such
notice. Upon receipt of such notice, the Employee's Authorization and Option
under the Plan shall terminate. If the Company does not receive such notice
prior to the next Date of Exercise, the Employee's Option shall be deemed to
have been exercised on such Date of Exercise.

        7. RESTRICTION UPON ASSIGNMENT. An Option granted under the Plan shall
not be transferable other than by will or the laws of descent and distribution,
and is exercisable during the Employee's lifetime only by the Employee. Except
as provided in Section 6(b) hereof, an Option may not be exercised to any extent
except by the Employee. The Company shall not recognize and shall be under no
duty to recognize any assignment or alienation of the Employee's interest in the
Plan, the Employee's Option or any rights under the Employee's Option.

        8. NO RIGHTS OF STOCKHOLDERS UNTIL SHARES ISSUED. With respect to shares
of Stock subject to an Option, an Employee shall not be deemed to be a
stockholder of the Company, and the Employee shall not have any of the rights or
privileges of a stockholder, until such shares have been issued to the Employee
or his or her nominee following exercise of the Employee's Option. No
adjustments shall be made for dividends (ordinary or extraordinary, whether in
cash

                                       7
<PAGE>   10

securities, or other property) or distribution or other rights for which the
record date occurs prior to the date of such issuance, except as otherwise
expressly provided herein.

        9. CHANGES IN THE STOCK AND CORPORATE EVENTS; ADJUSTMENT OF OPTIONS.

           (a) Subject to Section 9(c), in the event that the Committee, in its
sole discretion, determines that any dividend or other distribution (whether in
the form of cash, Stock, other securities, or other property), recapitalization,
reclassification, stock split, reverse stock split, reorganization, merger,
consolidation, split-up, spin-off, combination, repurchase, liquidation,
dissolution, or sale, transfer, exchange or other disposition of all or
substantially all of the assets of the Company, or exchange of Stock or other
securities of the Company, issuance of warrants or other rights to purchase
Stock or other securities of the Company, or other similar corporate transaction
or event, affects the Stock such that an adjustment is appropriate in order to
prevent dilution or enlargement of the benefits or potential benefits intended
to be made available under the Plan or with respect to an Option, then the
Committee shall, in such manner as it may deem equitable, adjust any or all of:

                (i) the number and kind of shares of Stock (or other securities
        or property) with respect to which Options may be granted (including,
        but not limited to, adjustments of the limitation in Section 3(a) on the
        maximum number of shares of Stock which may be purchased),

                (ii) the number and kind of shares of Stock (or other securities
        or property) subject to outstanding Options, and

                (iii) the exercise price with respect to any Option.

           (b) Subject to Section 9(c), in the event of any transaction or event
described in Section 9(a) or any unusual or nonrecurring transactions or events
affecting the Company, any affiliate of the Company, or the financial statements
of the Company or any affiliate, or of changes in applicable laws, regulations,
or accounting principles, the Committee, in its sole discretion, and on such
terms and conditions as it deems appropriate, either by the terms of the Option
or by action taken prior to the occurrence of such transaction or event and
either automatically or upon the Employee's request, is hereby authorized to
take any one or more of the following actions whenever the Committee determines
that such action is appropriate in order to prevent dilution or enlargement of
the benefits or potential benefits intended to be made available under the Plan
or with respect to any Option under the Plan, to facilitate such transactions or
events or to give effect to such changes in laws, regulations or principles:

                (i) To provide that all Options outstanding shall terminate
        without being exercised on such date as the Committee determines in its
        sole discretion;

                (ii) To provide that all Options outstanding shall be exercised
        prior to the Date of Exercise of such Options on such date as the
        Committee determines in its sole discretion and such Options shall
        terminate immediately after such exercises.

                                       8
<PAGE>   11

                (iii) To provide for either the purchase of any Option
        outstanding for an amount of cash equal to the amount that could have
        been obtained upon the exercise of such Option had such Option been
        currently exercisable, or the replacement of such Option with other
        rights or property selected by the Committee in its sole discretion;

                (iv) To provide that such Option be assumed by the successor or
        survivor corporation, or a parent or subsidiary thereof, or shall be
        substituted for by similar options, covering the stock of the successor
        or survivor corporation, or a parent or subsidiary thereof, with
        appropriate adjustments as to the number and kind of shares and prices;
        and

                (v) To make adjustments in the number and type of shares of
        Stock (or other securities or property) subject to outstanding Options,
        or in the terms and conditions of (outstanding Options, or Options which
        may be granted in the future.

           (c) No adjustment or action described in this Section 9 or in any
other provision of the Plan shall be authorized to the extent that such
adjustment or action would cause the Plan to fail to satisfy the requirements of
Section 423 of the Code. Furthermore, no such adjustment or action shall be
authorized to the extent such adjustment or action would result in short-swing
profits liability under Section 16 of the Securities and Exchange Act of 1934,
as amended, or violate the exemptive conditions of Rule 16b-3 unless the
Committee determines that the Option is not to comply with such exemptive
conditions. The number of shares of Common Stock subject to any Option shall
always be rounded to the next whole number.

           (d) The existence of the Plan and the Options granted hereunder shall
not affect or restrict in any way the right or power of the Company or the
stockholders of the Company to make or authorize any adjustment,
recapitalization, reorganization or other change in the Company's capital
structure or its business, any merger or consolidation of the Company, any issue
of stock or of options, warrants or rights to purchase stock or of bonds,
debentures, preferred or prior preference stocks whose rights are superior to or
affect the Stock or the rights thereof of which are convertible into or
exchangeable for Stock, or the dissolution or liquidation of the company, or any
sale or transfer of all or any part of its assets or business, or any other
corporate act or proceeding, whether of a similar character or otherwise.

        10. USE OF FUNDS; NO INTEREST PAID. All funds received or held by the
Company under the Plan shall be included in the general funds of the Company
free of any trust or other restriction and may be used for any corporate
purpose. No interest will be paid to any Employee or credited to any Employee's
Account with respect to such funds.

        11. DIVIDENDS.

            (a) Cash dividends and other cash distributions received by the
Agent with respect to Stock held in its custody hereunder will be credited to
each Employee's Account in accordance with such Employee's interests in such
Stock, and shall be applied, as soon as practicable after the receipt thereof by
the Agent, to the purchase in the open market at prevailing market prices of the
number of whole shares of Stock that may be purchased with such funds (after
deductions of any bank service fees, brokerage charges, transfer taxes, and any
other

                                       9
<PAGE>   12

transaction fee, expense or cost payable in connection with the purchase of such
shares of Stock and not otherwise paid by the Employer.)

            (b) All purchases of shares of Stock made pursuant to this Section
11 will be made in the name of the Agent or its nominee, and shall be
transferred and credited to the Account(s) of the Employees to which such
dividends or other distributions were credited. Dividends paid in the form of
shares of Stock will be allocated by the Agent, as and when received, with
respect to Stock held in its custody hereunder to the Account of each Employee
in accordance with such Employee's interests in such Stock. Property, other than
Stock or cash, received by the Agent as a distribution on Stock held in its
custody hereunder, shall be sold by the Agent for the accounts of Employees, and
the Agent shall treat the proceeds of such sale in the same manner as cash
dividends received by the Agent on Stock held in its custody hereunder.

        12. AMENDMENT, SUSPENSION OR TERMINATION OF THE PLAN. The Board may
amend, suspend, or terminate the Plan at any time and from time to time,
provided that approval by a vote of the holders of the outstanding shares of the
Company's capital stock entitled to vote shall be required to amend the Plan to:
(a) change the number of shares of Stock that may be sold pursuant to Options
under the Plan, (b) alter the requirements for eligibility to participate in the
Plan, or (c) in any manner that would cause the Plan to no longer be an
"employee stock purchase plan" within the meaning of Section 423(b) of the Code.

        13. ADMINISTRATION BY COMMITTEE; RULES AND REGULATIONS.

            (a) Appointment of Committee. The Plan shall be administered by the
Committee, which shall be composed of not less than two members of the Board,
each of whom shall be a "non-employee director" within the meaning of Rule 16b-3
which has been adopted by the Securities and Exchange Commission under the
Securities Exchange Act of 1934, as amended. Each member of the Committee shall
serve for a term commencing on a date specified by the Board and continuing
until the member dies, resigns or is removed from office by the Board. The
Committee at its option may utilize the services of an agent to assist in the
administration of the Plan, including establishing and maintaining an individual
securities account under the Plan for each Employee.

            (b) Duties and Powers of Committee. It shall be the duty of the
Committee to conduct the general administration of the Plan in accordance with
the provisions of the Plan. The Committee shall have the power to interpret the
Plan and the terms of the Options and to adopt such rules for the
administration, interpretation, and application of the Plan as are consistent
therewith and to interpret, amend or revoke any such rules. In its absolute
discretion, the Board may at any time and from time to time exercise any and all
rights and duties of the Committee under the Plan.

            (c) Majority Rule. The Committee shall act by a majority of its
members in office. The Committee may act either by vote at a meeting or by a
memorandum or other written instrument signed by a majority of the Committee.

                                       10
<PAGE>   13

            (d) Compensation; Professional Assistance; Good Faith Actions. All
expenses and liabilities incurred by members of the Committee in connection with
the administration of the Plan shall be borne by the Company. The Committee may,
with the approval of the Board, employ attorneys, consultants, accountants,
appraisers, brokers or other persons. The Committee, the Company and its
officers and directors shall be entitled to rely upon the advice, opinions or
valuations of any such persons. All actions taken and all interpretations and
determinations made by the Committee in good faith shall be final and binding
upon all Employees, the Company and all other interested persons. No member of
the Committee shall be personally liable for any action, determination or
interpretation made in good faith with respect to the Plan or the Options, and
all members of the Committee shall be fully protected by the Company in respect
to any such action, determination, or interpretation.

        14. DESIGNATION OF SUBSIDIARY CORPORATIONS. The Board shall designate
from among the Subsidiary Corporations, as determined from time to time, the
Subsidiary Corporation or Subsidiary Corporations whose Employees shall be
eligible to be granted Options under the Plan. The Board may designate a
Subsidiary Corporation, or terminate the designation of a Subsidiary
Corporation, without the approval of the stockholders of the Company.

        15. NO RIGHTS AS AN EMPLOYEE. Nothing in the Plan shall be construed to
give any person (including any Eligible Employee) the right to remain in the
employ of the Company, a Parent Corporation or a Subsidiary Corporation or to
affect the right of the Company, any Parent Corporation or any Subsidiary
Corporation to terminate the employment of any person (including any Eligible
Employee) at any time, with or without cause.

        16. TERM; APPROVAL BY STOCKHOLDERS. Subject to approval by the
stockholders of the Company in accordance with this Section, the Plan shall be
in effect until May 1, 2010, unless sooner terminated in accordance with Section
12. No Option may be granted during any period of suspension of the Plan or
after termination of the Plan. The Plan shall be submitted for the approval of
the Company's stockholders within twelve (12) months after the date of the
adoption of the Plan by the Board. Options may be granted prior to such
stockholder approval; provided, however, that such Options shall not be
exercisable prior to the time when the Plan is approved by the Company's
stockholders; and, provided, further, that if such approval has not been
obtained by the end of said 12-month period, all Options previously granted
under the Plan shall thereupon terminate without being exercised.

        17. EFFECT UPON OTHER PLANS. The adoption of the Plan shall not affect
any other compensation or incentive plans in effect for the Company, any Parent
Corporation or any Subsidiary Corporation. Nothing in this Plan shall be
construed to limit the right of the Company, any Parent Corporation or any
Subsidiary Corporation to: (a) establish any other forms of incentives or
compensation for employees of the Company, any Parent Corporation or any
Subsidiary Corporation or (b) grant or assume options otherwise than under the
Plan in connection with any proper corporate purpose, including, but not by way
of limitation, the grant or assumption of options in connection with the
acquisition, by purchase, lease, merger, consolidation or otherwise, of the
business, stock or assets of any corporation, firm or association.

                                       11
<PAGE>   14

        18. CONDITIONS TO ISSUANCE OF STOCK CERTIFICATES. The Company shall not
be required to issue or deliver any certificate or certificates for shares of
Stock purchased upon the exercise of Options prior to fulfillment of all the
following conditions:

            (a) The admission of such shares to listing on all stock exchanges,
if any, on which is then listed; and

            (b) The completion of any registration or other qualification of
such shares under any state or federal law or under the rulings or regulations
of the Securities and Exchange Commission or any other governmental regulatory
body, which the Committee shall, in its absolute discretion, deem necessary or
advisable; and

            (c) The obtaining of any approval or other clearance from any state
or federal governmental agency which the Committee shall, in its absolute
discretion, determine to be necessary or advisable; and

            (d) The payment to the Company of all amounts which it is required
to withhold under federal, state or local law upon exercise of the Option; and

            (e) The lapse of such reasonable period of time following the
exercise of the Option as the Committee may from time to time establish for
reasons of administrative convenience.

        19. NOTIFICATION OF DISPOSITION. Each Employee shall give prompt notice
to the Company of any disposition or other transfer of any shares of Stock
purchased upon exercise of an Option if such disposition or transfer is made:
(a) within two (2) years from the Date of Grant of the Option, or (b) within one
(1) year after the transfer of such shares of Stock to such Employee upon
exercise of such Option. Such notice shall specify the date of such disposition
or other transfer and the amount realized, in cash, other property, assumption
of indebtedness or other consideration, by the Employee in such disposition or
other transfer.

        20. NOTICES. Any notice to be given under the terms of the Plan to the
Company shall be addressed to the Company in care of its Secretary and any
notice to be given to any Employee shall be addressed to such Employee at such
Employee's last address as reflected in the Company's records. By a notice given
pursuant to this Section, either party may designate a different address for
notices to be given to it, him or her. Any notice which is required to be given
to an Employee shall, if the Employee is then deceased, be given to the
Employee's personal representative if such representative has previously
informed the Company of his status and address by written notice under this
Section. Any notice shall have been deemed duly given if enclosed in a properly
sealed envelope or wrapper addressed as aforesaid at the time it is deposited
(with postage prepaid) in a post office or branch post office regularly
maintained by the United States Postal Service.

                                       12
<PAGE>   15

        21. HEADINGS. Headings are provided herein for convenience only and are
not to serve as a basis for interpretation or construction of the Plan.

                                  * * * * * * *

        I hereby certify that the ACLARA BioSciences, Inc. Employee Stock
Purchase Plan was adopted by the Board of Directors of ACLARA BioSciences, Inc.
on February 11, 2000.

        Executed at Mountain View, California on this ___th day of _______,
2000.

                                           ____________________________________
                                           ___________________________________
                                           Secretary

                                  * * * * * * *

        I hereby certify that the ACLARA BioSciences, Inc. Employee Stock
Purchase Plan was approved by the stockholders of ACLARA BioSciences, Inc. on
_________________, 2000.

        Executed at Mountain View, California on this ___th day of _______,
2000.

                                           ____________________________________
                                           ___________________________________
                                           Secretary

                                       13

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