Re: Holloway/Morgan

Harry Erwin (
Sun, 30 Jul 1995 16:50:05 -0400

In article <>, wrote:

> Many thanks to Guy Hoelzer for clarifying the position about genetic
> drift. I apologise for being dismissive about the paper on drift and
> brain growth without having read it (Always a mistake!) Can anyone give
> me a reference to it please?

Possibly the most accessible reference is John Maynard Smith, Evolutionary
Genetics, Oxford, 1989, 144ff. How rapidly will heterozygosity be lost
from a fertile adult population of size N? Answer: the probability of
heterozygosity drops by about (2N-1)/(2N) per generation just based on
drift. Eventually the population will reach stability with the probability
of gene loss equalling the probability of mutation. The time for a
population to reach this equilibrium is about N generations. Hence a
highly homozygous population must have gone through a recent population

Harry Erwin
Home Page: (try again if necessary)
PhD student in comp neurosci: "Glitches happen" & "Meaning is emotional"