translating DNA question

Tom A. L'Heureux talheur at rs6000.cmp.ilstu.edu
Sat Jul 22 18:34:53 EST 1995


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Graham Dellaire (popa0206 at PO-Box.McGill.CA) wrote:
: >   monty at watson.open.ac.uk (Tony Hirst) writes:
: >  Another novice question....
: >
: >  the complementary strands of DNA, when trnascribed between two points, will


: >  translate to two different sequences depending on which strand of the helix


: >  is transcribed.
: >
: >  Qn: are the decoded complementary sequences both necessarily 'useful' (i.e.


: >  not nonsensical) or does DNA employ complementarity solely to facilatate
: >  replication and repair?

: Both strands can yield functional proteins... I think a good example would be
viral DNA which
: can have different functional proteins encoded by the same DNA but in differen

t reading frames in
: on either strand for a given section of DNA ( Adeno-2 for example).  This is p

robably because
: of constraints on size of the virus' genome.  In mammalian cells you have the
Rag-1 and Rag-2
: genes (responsible for VDJ recombinase activity) that are convergently transcr

ibed... for this reason
: they are hypothesized to have been derived from a fungal transposable element
many eons ago.


:  The obverse of this is that as well as multiple
: -  coding over a single sequence through frameshifts, multiple coding is
: -  achieved through DNA's dual-strand nature.....
: -

    In addition, it is easier to check the accuracy of sequencing of the
DNA if one can look at the complimentary strand after replication.



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