Critical rate of mutations

tivol at tethys.ph.albany.edu tivol at tethys.ph.albany.edu
Tue Jun 14 14:59:18 EST 1994


Rafael Najmanovich wrote that a larger genome decreases mutation probability
at a vital locus.  This is incorrect if the rates of the DNA-altering reac-
tions are equal to the products of the concentrations of the reactants.  If
the extra DNA were folded so as to hide a vital locus from the environment,
then extra DNA would be a help, but otherwise the rates of modification at a
particular locus would be affected only to a small degree.  This, of course,
might be enough to allow the survival of a genome which otherwise would die,
but is it enough to "encourage" the addition of non-productive DNA to an ex-
isting genome, or is the "cost" of producing the extra DNA greater than the
benefit?  It is, IMHO, more likely that the non-coding DNA either has func-
tions of which we know nothing, or it is in transition (having recently been 
functional until the last mutation, or about to become functional when its) 
functional until the last mutation, or about to become functional when its
next mutation[s] occur).

					Yours,

					Bill Tivol



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