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Population size and molecular clock?

Joe Felsenstein joe at evolution.genetics.washington.edu
Thu Dec 31 12:46:00 EST 1998

In article <76ecbl$243 at net.bio.net>, Guy Hoelzer  <hoelzer at med.unr.edu> wrote:
>It is a fundamental principle of the neutral theory of molecular evolution
>that there is no relation between population size and clock rate.  The
>reasoning is as follows:

The short answer is that Guy is correct (as is another poster who said the

That is the answer that Mortberg was looking for.

The long answer is that it is almost true, but not quite so.  Mutants are
neutral if |s| < 1/(4N).  Thus when   N  is small, more mutants are
neutral for that period.

This has been the basis of arguments by Ohta and others as to how
constancy of substitution per unit time could be predicted, when the
generation times vary among lineages.

However the "first cut" is that Guy is correct.

Joe Felsenstein         joe at genetics.washington.edu
 Dept. of Genetics, Univ. of Washington, Box 357360, Seattle, WA 98195-7360 USA

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