dkomo wrote:
> Tim Tyler wrote:
> 

> Why does it have to be the subject of drift?  It could simply be an
> allele which is not under selection and whose frequency remains pretty
> constant in a particular human subpopulation.
> 

> 
>>Where is the evidence that the spectrum of iris colourations observed
>>in human populations is due to drift?
> 
> 
> False dichotomy.  It's not selection *or* drift (or even both
> operating at the same time).  Iris colourations could simply be neural
> traits that are subject to neither, being in Hardy-Weinberg
> equilibrium.
> 
OK, hands up all those who have studied the assumptions for HWE and 
still believe that it's a good model of reality?

In this particular case, the fact that the population is finite (and the 
sub-populations are smaller) means that drift WILL occur.  It's just a 
fact of life (and death).  And it's difficult to see how you can have a 
polymorphism without one of the two acting at some stage.

Bob

-- 
Bob O'Hara

Dept. of Mathematics and Statistics
P.O. Box 4 (Yliopistonkatu 5)
FIN-00014 University of Helsinki
Finland
Telephone: +358-9-191 23743
Mobile: +358 50 599 0540
Fax:  +358-9-191 22 779
WWW:  http://www.RNI.Helsinki.FI/~boh/
Journal of Negative Results - EEB: http://www.jnr-eeb.org
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