EXHIBIT 10.15


                           WARRANT PURCHASE AGREEMENT

     This Warrant Purchase  Agreement (this "AGREEMENT") is executed this 19 day
of June, 2000, by INFORMAX,  INC., a Delaware corporation (the "BORROWER" or the
"COMPANY"),  in favor of PNC Bank,  National  Association,  a  national  banking
association  (the  "BANK"),  in  accordance  with the terms of that certain Loan
Agreement  dated May 6, 1999,  between the Company and the Bank, as amended (the
"LOAN  AGREEMENT").  In connection  with  Amendment No. 5 to the Loan  Agreement
dated of even date herewith,  between the Company and the Bank  ("AMENDMENT  NO.
5"), the Company has agreed to issue to the Bank warrants (each, a "WARRANT") to
purchase one fully paid and  nonassessable  share of the non-voting common stock
of the Company,  par value [$0.01] per share (the "NON-VOTING COMMON STOCK"), in
an amount equal to (i) 9,000 shares of Non-voting  Common Stock; and (ii) if any
amount is outstanding on the Bridge Note on September 19, 2000, 6,000 additional
shares of  Non-Voting  Common  Stock (the  "EXERCISE  QUANTITY").  The shares of
Non-Voting  Common  Stock  purchasable  upon  exercise of the  Warrants  and the
purchase  price per Warrant are referred to herein as the  "WARRANT  SHARES" and
the  "EXERCISE  PRICE",  respectively.  Where  shares of the common stock of the
Company are referenced herein without a "Non-Voting"  prefix,  such shares shall
be deemed to encompass both shares of the Company's  Non-Voting Common Stock and
shares  of the  Company's  voting  common  stock,  par  value  $0.01  per  share
(collectively, the "Common Stock").

     NOW,  THEREFORE,  in  consideration  of the  foregoing,  the  covenants and
agreements hereinafter set forth and other good and valuable consideration,  the
receipt and  sufficiency of which are hereby  acknowledged,  and intending to be
legally bound hereby, the Company and the Bank agree as follows:

1. GRANT OF WARRANTS. The Company hereby grants to the Bank Warrants to purchase
up to that  number of shares  which  constitute  the  Exercise  Quantity  of the
Non-Voting Common Stock on the date of purchase. Each Warrant initially shall be
exercisable for one share of Non-Voting  Common Stock. In  consideration  of the
grant of the  Warrants to the Bank,  the Bank has paid to the  Company  $.01 per
Warrant by personal check.  The Bank and any subsequent  registered  holder of a
Warrant (each, a "HOLDER")  shall have the rights and  obligations  set forth in
this Agreement and in the warrant  certificate  evidencing  such Warrant,  which
shall be  substantially  in the form  attached  hereto as Exhibit A (a  "WARRANT
CERTIFICATE").

2. WARRANT CERTIFICATE.

     (a) Form of Warrant  Certificate.  Each  Warrant  shall be  evidenced  by a
Warrant  Certificate.   Each  Warrant  Certificate  shall  have  such  marks  of
identification  or designation and such legends or  endorsements  thereon as the
Company  deems  appropriate,  so long as they  are  not  inconsistent  with  the
provisions of this  Agreement,  or as are required to comply with any applicable
law, rule or regulation or with any rule or regulation of any stock  exchange on
which the Non-Voting Common Stock may from time to time be listed.  Each Warrant
Certificate shall entitle the Holder thereof to exercise such number of Warrants
as shall be set forth  thereon at the Exercise  Price in effect on the date such
Warrant Certificate is delivered by the Company to such

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Holder;  provided,  that the number of Warrants and the Exercise  Price shall be
subject to adjustment as provided herein. Each Warrant Certificate shall provide
for a "net issuance  option,"  which will allow the Holder  thereof to surrender
some of the Warrants  evidenced thereby for cancellation and receive in exchange
for other Warrants evidenced thereby shares of Non-Voting Common Stock,  without
the  payment of any cash,  on the basis of a formula  set forth in such  Warrant
Certificate.

   (b) Signature and Registration.

       (i)  The Warrant Certificates shall be manually executed on behalf of the
   Company by its Chairman of the Board, its President or any Vice President and
   shall be manually attested by the Secretary or an Assistant  Secretary of the
   Company.

       (ii) The Company  will keep or cause to be kept at its  principal  office
   books for the  registration and transfer of the Warrant  Certificates  issued
   hereunder.

     (c) Transfer,  Split-Up,  Combination and Exchange of Warrant Certificates.
Subject  to  compliance  with all  applicable  laws and the  provisions  of this
Agreement,  at any time prior to the  close of  business  on 2007,  [2007]  (the
"FINAL EXPIRATION DATE"), any Warrant Certificate or Warrant Certificates may be
transferred,  split up, combined or exchanged for another Warrant Certificate or
Warrant  Certificates,  entitling the Holder or Holders  thereof to exercise the
same  number of  Warrants as the  Warrant  Certificate  or Warrant  Certificates
surrendered  to the Company by the Holder  thereof then  entitled such Holder to
exercise.  Any Holder  desiring to transfer,  split up,  combine or exchange any
Warrant  Certificate or Warrant  Certificates shall make such request in writing
delivered to the Company, and shall surrender the Warrant Certificate or Warrant
Certificates  to be  transferred,  split  up,  combined  or  exchanged,  at  the
principal  office of the Company.  Thereupon  the Company  shall  deliver to the
person  or  persons   entitled   thereto  a  Warrant   Certificate   or  Warrant
Certificates, as the case may be, as so requested.

   (d) Subsequent Issuance of Warrant Certificates. Subsequent to their original
issuance,   no  Warrant   Certificates   shall  be  issued  except  (i)  Warrant
Certificates  issued  upon any  transfer,  combination,  split up or exchange of
Warrant Certificates  pursuant to Section 2(c), (ii) Warrant Certificates issued
in replacement or mutilated, destroyed, lost or stolen Warrant Certificates, and
(iii) any Warrant  Certificate  issued pursuant to Section 3(d) upon the partial
exercise of any Warrant  Certificate to evidence the unexercised portion of such
Warrant Certificate.

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3. EXERCISE OF WARRANTS; EXERCISE PRICE.

   (a) The Holder of any Warrant Certificate may exercise the Warrants evidenced
thereby in whole or in part by surrendering such Warrant  Certificate,  with the
form of election to exercise  attached  thereto duly completed and executed,  to
the Company at its principal office,  together,  to the extent  necessary,  with
payment of the aggregate Exercise Price for the Warrants being exercised,  at or
prior to the close of business on the Final Expiration Date.

   (b) The Exercise  Price for each Warrant shall  initially be $10.00 per share
of Non-Voting  Common Stock,  which the Company  represents  and warrants to the
Bank to be the fair market value per share of the Non-Voting  Common Stock as of
the date of this  Agreement  based on the valuation  used for the Weiss,  Peck &
Greer  acquisition  of Borrower's  Non-Voting  Common Stock.  The Exercise Price
shall be subject to  adjustment  from time to time as  provided in Section 6 and
shall be payable in accordance with Section 3(c).

   (c) Upon  receipt  of a Warrant  Certificate,  with the form of  election  to
exercise duly  completed and executed,  accompanied  by payment of the aggregate
Exercise Price for the Warrants being  exercised,  except to the extent that the
Holder  thereof has  determined  to use the net issuance  option,  and an amount
equal to any  applicable  transfer  taxes  required to be paid by such Holder in
accordance  with Section 5(c) in cash or by certified  check or cashier's  check
payable to the order of the Company, the Company shall promptly: (i) requisition
from any transfer  agent of the  Non-Voting  Common  Stock or  otherwise  obtain
certificates  for  the  number  of  shares  of  Non-Voting  Common  Stock  being
purchased;  (ii) when  appropriate,  prepare or cause to be prepared a check for
the amount of cash to be paid in lieu of the issuance of a  fractional  share in
accordance with Section 7; (iii) after receipt of such  certificates,  cause the
same to be  delivered to or upon the order of such  Holder,  registered  in such
name or names as designated by such Holder;  and (iv) when appropriate,  deliver
such check to or upon the order of such Holder.  The Company hereby  irrevocably
authorizes each transfer agent of the Non-Voting Common Stock to comply with all
such requests from the Company in accordance with this Section 3(c).

   (d) If the Holder of any Warrant Certificate shall exercise less than all the
Warrants  evidenced thereby,  a new Warrant  Certificate  evidencing a number of
Warrants equal to the number of Warrants  remaining  unexercised shall be issued
by the Company to such Holder or to its duly authorized assigns,  subject to the
provisions of Section 7.

4. CANCELLATION OF WARRANT CERTIFICATES. All Warrant Certificates surrendered to
the Company for exercise,  transfer,  split up, combination or exchange shall be
canceled  by it, and no  Warrant  Certificates  shall be issued in lieu  thereof
except as expressly permitted by the provisions of this Agreement.

5. RESERVATION AND AVAILABILITY OF COMMON STOCK; TAXES.

   (a) The Company  shall,  at all times,  reserve and keep available out of its
authorized and unissued  shares of Non-Voting  Common Stock or out of any shares
of Non-Voting Common

                                      -3-

<PAGE>

Stock held in its treasury that number of shars of Non-Voting  Common Stock that
will  from time to time be  sufficient  to permit  the  exercise  in full of all
outstanding Warrants.

   (b) The Company shall take all such action as may be necessary to ensure that
all  shares of  Non-Voting  Common  Stock  delivered  upon the  exercise  of any
Warrants shall, at the time of delivery of the  certificates  for such shares of
Non-Voting  Common Stock, be duly  authorized,  validly  issued,  fully paid and
nonassessable.

   (c) The Company  shall pay when due and payable any and all federal and state
transfer taxes and charges (other than any applicable  income taxes) that may be
payable in respect of the  issuance or delivery  of Warrant  Certificates  or of
certificates for shares of Non-Voting  Common Stock receivable upon the exercise
of any Warrants;  provided,  however,  that the Company shall not be required to
pay any tax that may be payable in respect of the  issuance  and delivery of any
Warrant Certificate or stock certificate registered in a name other than that of
the Holder of the Warrant Certificate that has been surrendered.

6. ADJUSTMENTS.

     (a) General. The Exercise Price, the number of outstanding Warrants and the
number  and kind of  stock or other  securities  or  property  purchasable  upon
exercise of a Warrant shall be subject to adjustment  from time to time pursuant
to the terms of this Section 6.

     (b) Dilutive Issuances.

          (i) Special Definitions. For purposes of this Section 6, the following
     definitions shall apply:

               (A) "Additional  Shares of Common Stock" shall be mean all shares
          of Common Stock issued (or, pursuant to Section  6(b)(iii),  deemed to
          be issued) by the Company  after the Original  Issue Date,  other than
          shares of Common Stock issued or issuable:

               (I)      upon   conversion   or  exchange   of  any   Convertible
                        Securities  outstanding  on  the  Original  Issue  Date,
                        including,  but not limited to, any shares  issued to or
                        issuable  pursuant to any  antidilution  protections  in
                        existence  on the date hereof  that  operate in favor of
                        the Holders of such Convertible Securities;

               (II)     upon exercise of any Options outstanding on the Original
                        Issue Date;

               (III)    as  a  dividend   or   distribution   pro  rata  on  the
                        outstanding share of Common Stock;

               (IV)     as  a   result   of  any   stock   split,   combination,
                        reclassification,  exchange or substitution for which an
                        adjustment is provided in Section 6(c), (d) or (e)


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               (V)      upon exercise of any Warrants; or

               (VI)     to employees,  officers or directors of, or  consultants
                        or  advisors  to, the Company or any  subsidiary  of the
                        Company  pursuant to a stock  grant,  stock option plan,
                        employee stock purchase plan,  restricted  stock plan or
                        any other similar plan or agreement,  which grant,  plan
                        or  agreement  was approved by the Board of Directors of
                        the Company (the "BOARD") prior to its implementation.

               (B)  "Convertible   Securities"   shall  mean  any  evidences  of
          indebtedness,  shares  or  other  securities  directly  or  indirectly
          convertible into or exchangeable for shares of Common Stock.

               (C) "Option" shall mean any right, option or warrant to subscribe
          for,   purchase  or  otherwise  acquire  shares  of  Common  Stock  or
          Convertible   Securities,   excluding  rights,   options  or  warrants
          described in clause (V) or (VI) of Section 6(b)(i)(A).

               (D) "Original Issue Date" shall mean the date of this Agreement.

          (ii)  Issuance of  Securities  Deemed to be an Issuance of  Additional
     Shares of Common  Stock.  If at any time after the Original  Issue Date the
     Company issues any Options or Convertible Securities or fixes a record date
     for the  determination  of holders of any class of  securities  entitled to
     receive any Options or Convertible  Securities,  then the maximum number of
     shares of Common Stock (as set forth in the instruments  relating  thereto,
     without  regard  to any  provision  thereof  that  permits  or  requires  a
     subsequent  adjustment  of such number)  issuable upon the exercise of such
     Options or, in the case of Convertible Securities and Options therefor, the
     conversion or exchange of such Convertible Securities shall be deemed to be
     Additional  Shares of Common Stock  issued as of the time of such  issuance
     or, in case a record  date has been  fixed,  as of the close of business on
     such record date.  In any case in which  Additional  Shares of Common Stock
     are deemed to have been issued in accordance with the preceding sentence:

               (A) No further  adjustment  in the  Exercise  Price shall be made
          solely on account of the subsequent issuance of Convertible Securities
          or shares of Common  Stock upon the  exercise  of any such  Options or
          upon the  conversion  or exchange of any such  Convertible  Securities
          (including Convertible Securities issued upon exercise of Options);

               (B) If any such Options or Convertible  Securities by their terms
          provide for any change in the amount or kind of consideration  payable
          to the Company  upon the  exercise,  conversion  or exchange  thereof,
          whether  on account  of the  passage of time or for any other  reason,
          then the Exercise  Price  computed  based upon the  original  issuance
          thereof (or upon the occurrence of a record date with respect thereto)
          and as  subsequently  adjusted for other reasons shall,  upon any such
          change becoming  effective,  be recomputed based on the number of such
          Options or  Convertible  Securities  then  outstanding to reflect such
          change;


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<PAGE>

               (C) If the  number of shares of Common  Stock  issuable  upon the
          exercise,  conversion  or exchange of any such Options or  Convertible
          Securities  changes,   including,  but  not  limited  to,  any  change
          resulting from the operation of the anti-dilution  provisions thereof,
          then the Exercise  Price  computed  based upon the  original  issuance
          thereof (or upon the occurrence of a record date with respect thereto)
          and as  subsequently  adjusted for other reasons shall,  upon any such
          change becoming  effective,  be recomputed based on the number of such
          Options or  Convertible  Securities  then  outstanding to reflect such
          change;

               (D) If any such Options or the conversion or exchange  privileges
          represented by any such Convertible Securities expire or terminate not
          having been exercised, then the Exercise Price computed based upon the
          original  issuance  thereof (or upon the  occurrence  of a record date
          with respect  thereto) and as subsequently  adjusted for other reasons
          shall, upon any such expiration or termination becoming effective,  be
          recomputed  based  on  the  number  of  such  Options  or  Convertible
          Securities then outstanding to reflect such expiration or termination;
          and

               (E) No  readjustment  pursuant  to Clause  (B),  (C) or (D) above
          shall have the effect of  increasing  the Exercise  Price to an amount
          that  exceeds  the  lower of (x) the  Exercise  Price on the  original
          adjustment date prior to the original adjustment thereof on account of
          such  deemed  issuance  or (y) the  Exercise  Price  that  would  have
          resulted  from any other  issuances or deemed  issuances of Additional
          Shares of Common Stock between such original  adjustment  date and any
          such  readjustment  date without  taking into  account  such  original
          adjustment.

     In the event that the Company,  after the Original  Issue Date,  amends the
     terms of any Options or  Convertible  Securities  (whether  such Options or
     Convertible  Securities were outstanding on the Original Issue Date or were
     issued after the Original  Issue  Date),  then such Options or  Convertible
     Securities,  as so amended,  shall be deemed to have been issued  after the
     Original  Issue Date and the provisions of this Section 6(b) shall apply to
     them as of the date of such amendment.

          (iii) Adjustment of Exercise Price Upon Issuance of Additional  Shares
     of Common Stock.  In the event that the Company,  after the Original  Issue
     Date,  issues any Additional  Shares of Common Stock (including  Additional
     Shares of Common Stock deemed to be issued  pursuant to Section  6(b)(ii)),
     without  consideration  or for a  consideration  per  share  less  than the
     Exercise  Price  in  effect  on the date of and  immediately  prior to such
     issuance, then such Exercise Price shall be reduced, concurrently with such
     issuance,  to a  price  (calculated  to the  nearest  cent)  determined  by
     multiplying  such Exercise Price by a fraction,  (A) the numerator of which
     shall be (I) the number of shares of Common Stock  outstanding  immediately
     prior to such issuance, plus (II) the number of shares of Common Stock that
     the aggregate  consideration  received or to be received by the Company for
     the total  number of  Additional  Shares  of Common  Stock so issued  would
     purchase at such Exercise Price; and (B) the denominator of which


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     shall be (I) the number of shares of Common Stock  outstanding  immediately
     prior to such issuance,  plus (II) the number of such Additional  Shares of
     Common Stock so issued.  For purposes of this Section  6(b)(iii),  (y) if a
     record date is set for the  issuance or deemed  issuance of any  Additional
     Shares of Common  Stock,  then the close of  business  on such  record date
     shall be  treated  as the time of  issuance  of such  Additional  Shares of
     Common Stock;  and (z) all shares of Common Stock  issuable upon  exercise,
     conversion  or exchange  or Options or  Convertible  Securities  (including
     Convertible  Securities  issuable  upon  exercise of  Options)  outstanding
     immediately prior to such issuance shall be deemed to be outstanding (other
     than any shares  excludable  from the definition of  "Additional  Shares of
     Common Stock" in accordance with Section 6(b)(i)(A)(V) or (VI)).

          (iv)  Determination  of  Consideration.  For  purposes of this Section
     6(b), the aggregate  consideration received by the Company for the issuance
     of any Additional Shares of Common Stock shall be computed as follows:

               (A) Cash and Property. Such considerations shall:

               (I)      insofar  as it  consists  of cash,  be  computed  as the
                        aggregate of cash received by the Company;

               (II)     insofar as it consists  of  services  or property  other
                        than cash,  be computed as the fair market value thereof
                        at the  time of such  issuance,  as  determined  in good
                        faith by the Board; and

               (III)    in the event that Additional  Shares of Common Stock are
                        issued together with other shares or securities or other
                        assets  for a  combined  consideration,  be the pro rata
                        portion of such  consideration so received,  computed as
                        provided in clauses (I) and (II) above, as determined in
                        good faith by the Board.

               (B) Options and Convertible  Securities.  The  consideration  per
          share  received by the Company for  Additional  Shares of Common Stock
          deemed to have been issued pursuant to Section  6(b)(ii),  relating to
          Options and Convertible Securities, shall be determined by dividing

               (I)      the total amount,  if any, received or receivable by the
                        Company  as  consideration  for  the  issuance  of  such
                        Options  or  Convertible  Securities,  plus the  minimum
                        aggregate  amount of  additional  consideration  (as set
                        forth  in  the  instruments  relating  thereto,  without
                        regard to any provision thereof that permits or requires
                        a subsequent  adjustment of such consideration)  payable
                        to the Company  upon the  exercise of such Options or in
                        the   conversion   or  exchange   of  such   Convertible
                        Securities  or, in the case of Options  for  Convertible
                        Securities, the exercise of such Options for Convertible
                        Securities  and  the  conversion  or  exchange  of  such
                        Convertible Securities, by


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               (II)     the  maximum  number of  shares of Common  Stock (as set
                        forth  in  the  instruments  relating  thereto,  without
                        regard to any provision thereof that permits or requires
                        a subsequent  adjustment  of such number)  issuable upon
                        the  exercise  of  such  Options  or the  conversion  or
                        exchange of such Convertible  Securities or, in the case
                        of Options for Convertible  Securities,  the exercise of
                        such  Options  for   Convertible   Securities   and  the
                        conversion or exchange of such Convertible Securities.

          (v)  Termination  of  Adjustment   Rights.   All  rights  relating  to
     adjustment  of the  Exercise  Price  granted  pursuant to this Section 6(b)
     shall  terminate  and be of no further  force or effect upon the earlier of
     (i) an Automatic Conversion (as defined in the Certificate of Designations,
     Powers,  Preferences  and  Rights of the  Series A  Preferred  Stock of the
     Company,  the  "Certificate  of  Designation")  of the  Company's  Series A
     Preferred  Stock,  or (ii) any time at which  no  shares  of the  Company's
     Series A Preferred Stock are outstanding.

     (c) Adjustment for Stock Splits and  Combinations.  If the Company,  at any
time or from time to time,  after the Original  Issue Date effects a subdivision
of the  outstanding  Non-Voting  Common  Stock,  the  Exercise  Price in  effect
immediately before that subdivision shall be proportionately  decreased.  If the
Company,  at any time or from  time to  time,  after  the  Original  Issue  Date
combines the outstanding  shares of Non-Voting  Common Stock, the Exercise Price
in effect immediately before the combination shall be proportionately increased.
Any  adjustment in accordance  with this Section 6(c) shall become  effective at
the close of business on the date that the related  subdivision  or  combination
becomes effective.

     (d) Adjustment for Reorganization, Reclassification or Substitution. If the
shares of  Non-Voting  Common Stock  issuable  upon exercise of the Warrants are
changed into the same or a different number of shares of any class or classes of
stock of the Company or other securities or property of the Company,  whether by
capital reorganization,  reclassification or otherwise (other than a subdivision
or combination of shares provided for above in Section 6(e) or a stock dividend,
merger,  consolidation,  share exchange or sale of assets  provided for below in
Section 6(e)),  then,  from and after each such event,  each Holder of a Warrant
shall have the right to  exercise  such Warant for the amount and kind of shares
of stock and other securities and property receivable upon such  reorganization,
reclassification  or other  change  by a  holder  of the  number  of  shares  of
Non-Voting  Common  Stock for which such  Warrant  would  have been  exercisable
immediately prior to such reorganization, reclassification or change, subject to
further adjustment as provided herein.

     (e)  Adjustment  for  Merger,  Consolidation,  etc.  In case of any merger,
consolidation  or share exchange of the Compnay with or into another  person,  a
sale of all or substantially  all of the assets of the Company to another person
or any other  transaction  involving  the Company and  another  person  having a
similar   effect  (other  than  a  subdivision   or  combination  of  shares  or
reorganization,  reclassification  or other transaction  provided for above or a
stock dividend  provided for below),  then, from and after each such event, each
Holder of a Warrant shall have the right to exercise such Warrant for the amount
and kind of shares of stock and other  securities an dproperty  receivable  upon
such merger, consolidation, share exchange, sale or other


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transaction by a holder of the number or shares of Common stock for which such
Warrant would have been exercisable immediately prior to such merger,
consolidation, share exchange, sale or other transaction, subject to further
adjustment as provided herein.  In each such case, prior to and as a condition
to the consummation of any such transaction, appropriate adjustments (as
determined in good faith by the Board) shall be made in the provision of this
Section 6 with respect to the rights and interests of the Holders of the
Warrants, to the end that these provisions shall thereafter be applicable, in as
equivalent a manner as reasonably can be achieved, in relation to any shares of
stock, other securities or property thereafter deliverable upon exercise of the
Warrants.

     (f) Adjustment for Certain Dividends and Distributions.  If the Company, at
any time or from time to time, after the Original Issue Date makes or issues, or
fixes a record  date for the  determination  of holders of shares of  Non-Voting
Common Stock entitled to receive,  a dividend or other  distribution  payable in
additional shares of Non-Voting Common Stock,  then, and in each such event, the
Exercise  Price in effect  from and after the time of such  issuance  or, in the
event such a record  date has been  fixed,  the close of business on such record
date shall be equal to the producer of the Exercise Price in effect  immediately
prior to such time multiplied by a fraction:

          (i) the  numerator  of which  shall be the  total  number of shares of
     Non-Voting Common Stock issued and outstanding or issuable upon exercise of
     any Options or upon  conversion or exchange of any  Convertible  Securities
     issued and  outstanding  immediately  prior to the time of such issuance or
     the close of business on such record date; and

          (ii) the  denominator  of which shall be the total number of shares of
     Non-Voting Common Stock issued and outstanding or issuable upon exercise of
     any Options or upon  conversion or exchange of any  Convertible  Securities
     issued and  outstanding  immediately  prior to the time of such issuance or
     the close of  business on such  record  date,  plus the number of shares of
     Non-Voting  Common Stock issued or issuable in payment of such  dividend or
     distribution;  provided, however, that if such a record date has been fixed
     and such dividend is not fully paid or such  distribution is not fully made
     on the date set therefore,  then the Exercise Price then in effect shall be
     appropriately recalculated as of the close of business on such record date.

     (g) Adjustments for Other Dividends and Distributions.  If the Company,  at
any time or from time to time, after the Original Issue Date makes or issues, or
fixes a record date for the  determination  of holders of shares of Common Stock
entitled to receive, a dividend or other  distribution  payable in securities of
the Company or any  subsidiary of the Company other than shares of Common Stock,
then, and in each such event,  appropriate  provision shall be made so that each
Holder of a Warrant  exercised  after such  issuance or such record date, as the
case may be, shall receive,  in addition to the shares of Common Stock otherwise
receivable upon such exercise,  the amount of securities and other property,  if
any,  that  would  have been  received  by such  Holder  had such  Warrant  been
exercised  immediately  prior to such  issuance or the close of business on such
record date and the securities received upon such exercise been retained from


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the date of such  issuance  or such  record  date to and  including  the  actual
exercise date of such Warrant.

     (h) Adjustment in Number of Warrants. When any adjustment is required to be
made in the  Exercise  Price  pursuant  to this  Section  6, then the  number of
outstanding  Warrants  shall be  simultaneously  adjusted  to equal  the  number
determined  by dividing  (i) the  product of the number of Warrants  outstanding
immediately prior to such adjustment  multiplied by the Exercise Price in effect
immediately  prior to such  adjustment,  by (ii) the  Exercise  Price in  effect
immediately after such adjustment.

     (i)  Certificate  as to  Adjustment.  In  each  case  of an  adjustment  or
readjustment  of the Exercise Price pursuant to this Section 6, the Company,  at
its  expense,   shall  promptly  compute  such  adjustment  or  readjustment  in
accordance  with the  provisions  hereof and prepare a certificate  showing such
adjustment  or  readjustment,  and shall mail such  certificate,  by first class
mail,  postage  prepaid,  to each  registered  Holder of a Warrant a certificate
setting  forth  such  adjustment  and the  related  adjustment  in the number of
outstanding  Warrants and  describing in reasonable  detail the facts upon which
such adjustments are based.  The Company shall,  upon the written request at any
time of any Holder of a Warrant, furnish or cause to be furnished to such Holder
a certificate  setting forth (i) all such  adjustments  since the Original Issue
Date, (ii) the Exercise Price then in effect,  and (iii) the number of shares of
Common Stock and the amount,  if any, of other securities or property that would
then be receivable upon exercise of a Warrant.

7. FRACTIONAL SHARES.

     (a) The  Company  shall  not be  required  to issue  fractional  shares  of
Non-Voting  Common  Stock upon the  exercise of any  Warrants  or to  distribute
certificates that evidence fractional shares of Common Stock. In lieu of issuing
a fractional  share of  Non-Voting  Common  Stock,  the Company shall pay to the
Holder of any Warrants at the time such Warrants are exercised an amount in cash
equal to the same  fraction of the current  marker  value of one share of Common
Stock on the date that such Warrants are exercised.

     (b) For  purposes  hereof,  the current  market  value of a share of Common
Stock (or any other  security)  shall be the  closing  price per share of Common
Stock  (or  the  standard  unit  for  such  other   security)  on  the  date  of
determination. Such closing price shall be:

          (i) the last sale price,  regular  way, or, in case no such sale takes
     place,  the  average  of the  closing  bid and asked  prices on the date of
     determination,  in either case as reported  in the  principal  consolidated
     transaction  reporting system with respect to securities listed or admitted
     to trading on the New York Stock Exchange; or

          (ii) if the Common Stock (or such other class or series of securities)
     is not listed or  admitted to trading on the New York Stock  Exchange,  the
     last sale price,  regular way,  or, in case no such sale takes  place,  the
     average of the closing bid and asked  prices on such day, in either case as
     reported in the principal  consolidated  transaction  reporting system with
     respect to  securities  listed or  admitted  to  trading  on the  principal
     national


                                     - 10 -
<PAGE>

     securities  exchange  on which the  Common  Stock (or such  other  class or
     series of securities) is listed or admitted to trading; or

          (iii)  if  the  Common  Stock  (or  such  other  class  or  series  of
     securities) is not listed or admitted to trading on any national securities
     exchange,  the last quoted sale price or, if not so quoted,  the average of
     the  high bid and low  asked  prices  on such  day in the  over-the-counter
     market, as reported by the National Association of Securities Dealers, Inc.
     Automated  Quotations  System  or  such  other  system  then in use by such
     organization; or

          (iv) if the Common Stock (or such other class or series of securities)
     is not listed or admitted to trading on any  national  securities  exchange
     and prices therefor are not reported by such  organization,  the average of
     the closing bid and asked  prices as  furnished  by a  professional  market
     maker making a market in the Common Stock (or such other class or series of
     securities) selected by the Board; or

          (v) if the Common Stock (or such other class or series of  securities)
     is not so listed or  admitted  to trading  and prices  therefor  are not so
     reported or quoted,  the fair market value per share (or other  appropriate
     unit) as determined in good faith by the Board, whose  determination  shall
     be conclusive and binding on all Holders of Warrants.

8.  PIGGYBACK REGISTRATION.

     (a) If at any time the Company determines to file a registration  statement
(including  pursuant to the request of any security  holder of the Company which
has the right to  require  the  Company to file such a  registration  statement)
under the  Securities  Act of 1933, as amended (the "1933 ACT"),  to register an
offering of shares of Common Stock,  it must give to the Holders  written notice
of such  determination at least 15 days prior to each such filing. If, within 15
days after  receipt of any such notice,  any Holder so requests in writing,  the
Company must include in such registration  statement all of such Holder's shares
of Common Stock purchasable or purchased from time to time upon exercise of such
Holder's Warrants that such Holder requests to be so included.  All such Warrant
Shares, together with any other shares of Common Stock the holders of which have
the right to require the Company to include such shares in any such registration
statement, are sometimes referred to herein as the "REGISTRABLE SECURITIES."

     (b) Any  Registrable  Securities  of a Holder that are to be included in an
underwritten  public  offering  pursuant to this  Section 8 shall be offered and
sold upon such terms as the managing  underwriters thereof determine;  provided,
however,  that any such  terms  must be the same as the terms to which any other
holder of  Registrable  Securities  will be bound and must not be  substantially
different  from the terms  pursuant to which the Company and any other  security
holder  selling shares of Common Stock in such offering are selling such shares.
The managing  underwriters  may condition any Holder's  participation in such an
underwritten  public  offering upon such Holder's  execution of an  underwriting
agreement   containing   customary  terms  and   conditions.   If  the  managing
underwriters  for an underwritten  public offering  determine that the number of
shares of Common  Stock  proposed to be sold in such  offering  would  adversely
affect the  marketing of the shares of Common Stock  proposed to be sold in such
offering would  adversely  affect the marketing of the shares of Common Stock to
be sold by the Company therein or by the


                                     - 11 -
<PAGE>

person or persons who  exercised  their right to require the Company to register
such offering under the 1933 Act, then the number of shares that may be included
in the underwriting pursuant to this Section 8(b) shall be allocated,  first, to
the Company  and  Preferred  Holders as  provided  by the terms of the  Investor
Rights Agreement by and between the Company and certain holders of the Company's
Series A  Preferred  Stock,  dated  May 22,  1999;  and,  second,  to all  other
shareholders participating in such underwritten offering on a pro rata basis.

If any  Holder  which has  elected  to  participate  in an  underwritten  public
offering  determines  that it does not approve of the terms of any such offering
prior to the effectiveness of the related registration  statement under the 1933
Act, then such Holder may elect to withdraw  therefrom by giving  written notice
of such  withdrawal  to the Company and the managing  underwriters  delivered at
least ten (10)  business days prior to the  effective  date of the  registration
statement.   Any  Registrable   Securities   excluded  or  withdrawn  from  such
underwriting shall be excluded and withdrawn from the registration.

     (c) All  registration  rights granted under this Section 8 shall  terminate
and be of no further force or effect from and after the fifth anniversary of the
effective  date  under  the  1933  Act of the  registration  statement  for  the
Company's first firm commitment underwritten public offering of shares of Common
Stock (the "INITIAL  OFFERING").  A Holder shall not be entitled to exercise its
registration  rights  under this  Section 8 at any time that  (i)(A) the Initial
Offering has been completed;  (B) the Company is subject to and is in compliance
with the applicable reporting  requirements under the Securities Exchange Act of
1934, as amended;  and (C) all Warrant Shares  beneficially owned by such Holder
may be sold  pursuant  to Rule 144(k)  under the 1933 Act,  and (ii) all Warrant
Shares held by and issuable to such Holder (and its affiliates, partners, former
partners,  members  and  former  members)  may be sold under Rule 144 during any
ninety (90) day period. If at any time the Warrants are exercisable, in whole or
in part,  for any securities  other than shares of Non-Voting  Common Stock then
the provisions of this Section 8 shall apply equally to the  registration of any
offering of that class or series of securities.

     (d) In  connection  with any  offering  of Warrant  Shares  pursuant to the
provisions of this  Section,  Company and Holder shall be obligated to indemnify
each other (and the officers, directors and controlling Person thereof) pursuant
to the terms of Section 2.9 (entitled  "Indemnification")  of the  Non-Preferred
Holder Rights Agreement by and between the Company and certain of its investors,
executed March 29, 2000.

     (e) Notwithstanding  anything to the contrary herein, the Company shall not
be obligated to register any Warrants or Warrant  Certificates  pursuant to this
Agreement.

     (f) Notwithstanding anything to the contrary set forth herein:

          (i)  The  provisions  of  this  Section  8  shall  not  apply  to  any
     registration  statement that is being filed to register the offering of (A)
     securities  being  offered in the Initial  Offering,  (B)  securities to be
     issued solely in connection with the acquisition of any entity or business,
     (C)  securities   issuable  solely  pursuant  to  employee   benefit  plans
     (including  pursuant to the exercise of stock  options),  or (D) securities
     the offering of


                                     - 12 -
<PAGE>

     which is being  registered on a registration  form that does not permit the
     registration of the offering of securities for security holders.

          (ii) The Company may withdraw any registration  statement  referred to
     in this Section 8 in accordance with the provisions of the 1933 Act without
     thereby incurring any liability to any Holder of Warrants.

9.  AGREEMENT OF WARRANT  HOLDERS.  Every Holder of a Warrant,  by accepting the
same,  acknowledges and agrees with the Company and with every other Holder of a
Warrant that:

     (a) Each  Warrant  is  transferable  only by the  transfer  of the  Warrant
Certificate  that  evidences such Warrant upon the registry books of the Company
which  shall be  accomplished  by  surrendering  such  Warrant  Certificate  for
transfer at the Company's  principal  office,  duly endorsed or accompanied by a
proper instrument of transfer; and

     (b) The  Company  may deem and  treat the  person  in whose  name a Warrant
Certificate  is  registered  as the absolute  owner  thereof and of the Warrants
evidenced thereby for all purposes whatsoever,  notwithstanding any notations of
ownership or writing on such Warrant  Certificate  made by anyone other than the
Company or any other notice to the contrary.

10.  RESTRICTIONS ON TRANSFER.

     (a) The Warrants and the Warrant  Shares or the other  securities  issuable
upon  exercise of the Warrants may not be sold or otherwise  transferred  unless
either (i) such transaction  first shall have been registered under the 1933 Act
and any applicable state or other securities law or (ii) the Company first shall
have been  furnished  with an opinion of legal  counsel  or other  evidence,  in
either case  reasonably  satisfactory  to the  Company,  to the effect that such
transaction is exempt from the registration requirements of the 1933 Act and any
applicable state or other securities law.

     (b) The Holder of the Warrant, by acceptance hereof, acknowledges that this
Warrant, the shares of Non-Voting Common Stock to be issued upon exercise hereof
are being acquired solely for the Holder's own account and not a nominee for any
other  party,  and for  investment  and that the Holder will not offer,  sell or
otherwise  dispose of the Warrant,  the shares of Non-Voting  Common Stock to be
issued upon exercise hereof except under circumstances that will not result in a
violation of applicable federal and state securities laws.  Further,  the Holder
shall comply with such additional  reasonable  requests of the Company necessary
to enable the  shares of  Non-Voting  Common  Stock to be issued  upon  exercise
hereof in compliance with applicable state and federal securities laws.

     (c) The Holder of this Warrant agrees not to make any disposition of all or
any portion of the  Warrant or of the shares of  Non-Voting  Common  Stock to be
issued upon exercise  hereof to any Competitor of the Company.  For the purposes
of this Agreement, the term "COMPETITOR" means any person, partnership,  limited
liability company, corporation or other entity (other than the Company) which is
engaged as its principal line of business,  in the Company's  Business.  For the
purposes of this Agreement, the term "COMPANY'S BUSINESS"


                                     - 13 -

<PAGE>

means  the  business  of the  development  and  licensing  of  pharma-informatic
software tools of the type developed by the Company.

     (d) Each  certificate  evidencing  securities  issuable  upon exercise of a
Warrant shall bear a legend substantially in the following form:

     THE SECURITIES EVIDENCED HEREBY WERE ACQUIRED IN A TRANSACTION THAT WAS NOT
     REGISTERED  UNDER THE SECURITIES  ACT OF 1933, AS AMENDED (THE  "SECURITIES
     ACT"),  OR ANY  STATE  OR OTHER  SECURITIES  LAW.  THE  HOLDER  HEREOF,  BY
     ACQUIRING THIS  INSTRUMENT,  AGREES FOR THE BENEFIT OF INFORMAX,  INC. (THE
     "COMPANY")  THAT THE SECURITIES  EVIDENCED  HEREBY MAY BE SOLD,  PLEDGED OR
     OTHERWISE  TRANSFERRED ONLY (A)(1) PURSUANT TO AN AVAILABLE  EXEMPTION FROM
     REGISTRATION  UNDER THE  SECURITIES  ACT, OR (2)  PURSUANT TO AN  EFFECTIVE
     REGISTRATION  STATEMENT  UNDER THE  SECURITIES  ACT; AND (B) PURSUANT TO AN
     AVAILABLE EXEMPTION OR EFFECTIVE REGISTRATION UNDER ANY APPLICABLE STATE OR
     OTHER SECURITIES LAW.

               Notwithstanding the foregoing, such legend shall not be placed on
          any such certificate or shall be removed from any such certificate (i)
          at the request of the holder thereof, if such holder shall be entitled
          to sell  the  securities  to be  evidenced  or  evidenced  thereby  in
          accordance  with Rule 144(k) under the 1933 Act, or (ii) if the holder
          thereof  is  selling  the  securities  to be  evidenced  thereby  in a
          registered public offering in accordance with Section 8.

11.  WARRANT  CERTIFICATE  HOLDER  NOT  DEEMED A  STOCKHOLDER.  No Holder of any
Warrant,  as such,  shall be entitled to vote or receive  dividends  or shall be
deemed for any other  purpose the holder of the shares of Common  Stock or other
securities  which may at any time be issuable upon the exercise of such Warrant.
Nothing  contained  herein or in any Warrant  Certificate  shall be construed to
confer  upon  the  Holder  of any  Warrant,  as  such,  any of the  rights  of a
stockholder  of the  Company,  including  any right to vote for the  election of
directors or upon any other matter  submitted to  stockholders of the Company at
any meeting thereof,  to give or withhold consent to any corporate action, or to
receive notice of meetings or other actions  affecting  stockholders,  except as
otherwise  expressly  provided  herein or therein or until such Warrant has been
exercised in accordance with the provisions hereof and thereof.

12.  ISSUANCE  OF NEW  WARRANT  CERTIFICATES.  Notwithstanding  anything  to the
contrary  set forth herein or in the Warrant  Certificates,  the Company may, at
its option, issue new Warrant Certificates evidencing the Warrants, in such form
as may be approved  by the Board,  to reflect  any  adjustment  or change in the
Exercise  Price and the number or kind of stock or other  securities or property
purchasable upon exercise of the Warrants.



                                      -14-

<PAGE>


13.  AMENDMENT.  Except as otherwise  expressly  provided in this Agreement,  no
modification  or  amendment  hereof will be  effective  unless made in a writing
signed by  appropriate  officers  of the  parties  hereto.  Notwithstanding  the
foregoing, any term of this Agreement may be amended with the written consent of
the Company and Persons  holding a majority of the Warrants  and Warrant  Shares
and shall  automatically  apply to any Holder of Warrant  Shares  whether or not
such Holder consented to such Amendment.

14. CAPITALIZED  TERMS.  Capitalized terms used and not otherwise defined herein
shall have the meanings assigned to them in the Loan Agreement.

15.  SUCCESSORS AND ASSIGNS.  The terms of this Agreement  shall be binding upon
the Company and the Bank and their respective permitted successors and assigns.

16.  INTEGRATION.  This  Agreement  and the Warrant  Certificates  represent the
entire  agreement of the Company and the Bank with respect to the subject matter
hereof and thereof, and there are no promises, undertakings,  representations or
warranties  by either  relative  to the  subject  matter  hereof and thereof not
expressly set forth or referred to herein or in the Warrant Certificates.

17.  GOVERNING LAW; CONSENT TO JURISDICTION; WAIVER OF JURY TRIAL.

     THIS AGREEMENT AND ALL RELATED  INSTRUMENTS AND AGREEMENTS  SHALL BE DEEMED
     TO BE CONTRACTS MADE AND TO BE PERFORMED  ENTIRELY IN THE  COMMONWEALTH  OF
     PENNSYLVANIA, AND SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
     LAWS OF THE  COMMONWEALTH  OF  PENNSYLVANIA,  AND SHALL BE  GOVERNED BY AND
     CONSTRUED IN ACCORDANCE  WITH THE LAWS OF THE  COMMONWEALTH OF PENNSYLVANIA
     (WITHOUT GIVING EFFECT TO ANY PROVISIONS  THEREOF CONCERNING CHOICE OF LAW)
     AND THE  UNITED  STATES  OF  AMERICA.  THE  FEDERAL  COURTS  AND  COURTS OF
     PENNSYLVANIA LOCATED IN ALLEGHENY COUNTY, PENNSYLVANIA SHALL HAVE EXCLUSIVE
     JURISDICATION  OVER ANY  PROCEEDINGS IN CONNECTION  HEREWITH AND THEREWITH.
     EACH OF THE BANK AND THE COMPANY  HEREBY  WAIVES ANY RIGHT THAT IT MAY HAVE
     TO A TRIAL BY JURY OF ANY  DISPUTE  (WHETHER  A CLAIM  IN  TORT,  CONTRACT,
     EQUITY OR  OTHERWISE)  ARISING  UNDER OR RELATING TO THIS  AGREEMENT OR ANY
     RELATED MATTERS, AND ANY SUCH DISPUTE SHALL BE TRIED BEFORE A JUDGE SITTING
     WITHOUT A JURY.

                           [Signature Page to Follow]





                                      -15-

<PAGE>


     Witness  the due  execution  of this  Agreement  as of the date first above
written.


ATTEST:                                     INFORMAX, INC.



By:  /s/ Joseph E. Lehren                    By:  /s/  Alex Titomirov
   -----------------------------               ----------------------------
Name:    Joseph E. Lehren                    Name:     Alex Titomirov
     ---------------------------                 --------------------------
Title:   CFO                                 Title:    CEO/Chairman
      --------------------------                  -------------------------



                                            PNC BANK,
                                            NATIONAL ASSOCIATION


                                            By:  /s/ Katharine Kappler
                                               ----------------------------
                                            Name:    Katharine Kappler
                                                 --------------------------
                                            Title:   Managing Director
                                                  -------------------------







                                      -16-