GENETIC VECTORS, INC.
                        5201 N.W. 77TH AVENUE, SUITE 100
                              MIAMI, FLORIDA 33166

                                 October 1, 1999



DNA Sciences, Inc.
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Gentlemen:

            This  letter  confirms  the intent of  Genetic  Vectors,  Inc.  (the
"BUYER")  to acquire all of the  outstanding  capital  stock (the "DNA  SCIENCES
SHARES") of DNA Sciences,  Inc., a ______________  corporation ("DNA SCIENCES"),
from the shareholders of DNA Sciences (each a "SHAREHOLDER" and collectively the
"SHAREHOLDERS").

            1. THE  ACQUISITION.  The transaction will be structured as a merger
(the "MERGER") of DNA Sciences with and into the Buyer, so that the Shareholders
can receive  tax-free  treatment  for the  consideration  received for their DNA
Sciences Shares,  if permitted by the Internal Revenue Code of 1986, as amended.
The parties  will use their best  efforts to account  for this merger  using the
"pooling of interests" method of accounting.

            2.  PURCHASE  PRICE.  In exchange for the DNA Sciences  Shares,  the
Shareholders  will receive 450,000 shares of common stock,  par value $0.001 per
share (the "BUYER'S COMMON STOCK"), of the Buyer.

            3. BOARD OF  DIRECTORS.  The  Agreement  (as  defined  herein)  will
provide that the  Shareholders  of DNA Sciences shall have the right to nominate
one (1) member to the Buyer's Board of Directors.

            4.  CLOSING.  The  Merger  will be  consummated  at a  closing  (the
"CLOSING") to be held at the offices of Buyer's attorneys, on a date which shall
be on or before November 30, 1999.

            5. EMPLOYMENT AGREEMENTS.  The Agreement will provide that the Buyer
will enter into an employment  agreement with Richard Tullis, Eric Wilkinson and
Jerome  Steifel.  The terms of each of these  agreements will be satisfactory to
the parties thereto.




DNA Sciences, Inc.
October 1, 1999
Page 2


6. DUE DILIGENCE  INSPECTION.  After the signing of this letter,  each party may
make   examinations  and  inspections  of  each  others   financial   condition,
properties,  legal  matters,  business and affairs.  Each party will cause their
attorneys, accountants and other advisors and agents to cooperate with the other
in its  investigation  and to  make  their  files  and  work  papers  available.
Consummation   of  the  purchase  will  be  subject  to  each  party   obtaining
satisfactory results in its due diligence investigation; PROVIDED, HOWEVER, that
(a) each party will  submit to the other party a request  for  documents  within
five (5) days of the execution date of this letter;  (b) each party will respond
to the request for documents within ten (10) days after receipt of such request;
and (c) each party will  complete its review of such  documents  within ten (10)
days of receipt  of such  documents.  Thereafter,  each party will have five (5)
days to provide the other party with written notice of its desire not to proceed
because the results of the investigation were not satisfactory.

            7.  NO-SHOP.  From the date of this letter until  December 31, 1999,
neither DNA Sciences nor its  shareholders,  officers,  directors,  employees or
other agents will, directly or indirectly,  take any action to solicit, initiate
or encourage any  acquisition of  substantially  all of the assets or any of the
stock of DNA Sciences or any  transaction  similar to the  transaction  outlined
herein, nor will they entertain any unsolicited  proposals or approaches in this
regard.

            8. COSTS.  Each party agrees to pay,  without right of reimbursement
from the  other  party and  regardless  of  whether  or not the  transaction  is
consummated,  the costs  incurred  by it in  connection  with this  transaction,
including legal fees and other costs  incidental to the negotiation of the terms
of the transaction and the preparation of related documentation. Each party will
indemnify  and hold the other  harmless  from any  loss,  liability  or  expense
(including,  without  limitation,  legal fees)  resulting from the  indemnifying
party's breach of this Section 8.

            9. PRESS RELEASES. Prior to the Closing, neither party will make any
press release,  statement to employees or other disclosure of this letter or the
transaction  contemplated  hereby without the prior written consent of the other
party, except as required by law.

            10. NON-BINDING LETTER OF INTENT.  Except for Sections 6, 7, 8 and 9
hereof,  this letter is an expression of interest only and is not intended to be
a binding letter of intent,  and the general principles set forth in this letter
shall not  constitute  an  agreement to  consummate  the  transaction  described
herein. Upon the satisfactory  completion of the due diligence  investigation by
each of the parties  hereto as described in Section 6 hereof which confirms each
party's intent to consummate the transaction for the purchase price described in
Section 2  hereof,  the  parties  will  proceed  to use their  best  efforts  to
negotiate the definitive  terms of this  transaction and enter into a formal and
binding  agreement  (the  "AGREEMENT")  which sets  forth such  representations,
warranties,  covenants,  indemnifications and other provisions as are acceptable



DNA Sciences, Inc.
October 1, 1999
Page 3


to the  parties  in their  sole  discretion.  This  letter  of  intent is not an
agreement to enter into any definitive agreement.

11. COUNTERPARTS.  This letter may be signed in counterparts, each of which will
be considered an original and all of which will constitute the same document.

      If this letter  accurately  reflects your  understanding,  please indicate
your agreement by signing both enclosed  copies of this letter and returning one
executed copy to me by October 5, 1999.

                                    Sincerely yours,

                                    GENETIC VECTORS, INC.

                                    By:__________________________________
                                    Name:  Mead M. McCabe, Jr.
                                    Title: President


ACCEPTED AND AGREED THIS _____
DAY OF OCTOBER, 1999:

DNA SCIENCES, INC.

By:_____________________________
Name:___________________________
Title:____________________________


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[Shareholders]