In article <5nmp30$ooh at ruacad.runet.edu>, rkliman at runet.edu (Richard M
Kliman) wrote:
> >Many mutations in protein coding DNA do not result in a change in amino
> >acid due to the redundancy of code. Thus these occur despite natural
> >selection as there is no phenotype to be selected.
>> This is not always true. There is considerable evidence for selection
> acting on silent substitutions, probably favoring those that increase the
> efficiency and/or fidelity of translation.
The fact that many substitutions do not result in AA changes IS true. Some
of these may be select for or against due to tendancies related to G/C bias
etc. However it seems reasonably to say that most will simply be neutral -
i.e. they had no affect on phenotype and were fixed by drift. Indeed is
seems likely that many AA replacement substitutions will also be between
AAs that have a minimal effect on the protein structure (i.e. changes tend
to be withing AA groupings with respect to size and hydrophobicity).
Andrew
======================================================================
Andrew Rambaut, EMAIL - Andrew.Rambaut at zoology.ox.ac.uk
Zoology Department, WWW - http://evolve.zoo.ox.ac.uk/
University of Oxford, TEL - +44 1865 271272
South Parks Road, Oxford, UK FAX - +44 1865 271249
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======================================================================
Andrew Rambaut, EMAIL - Andrew.Rambaut at zoology.ox.ac.uk
Zoology Department, WWW - http://evolve.zoo.ox.ac.uk/
University of Oxford, TEL - +44 1865 271272
South Parks Road, Oxford, UK FAX - +44 1865 271249
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