phillip smith wrote:

> Evolution has been described as changes in gene frequencies. I have myself
> espoused this point of view. I am beginning to have some doubts. The gene
> centered view of selection with coefficients for each allele where the
> differences of genomic back ground are supposed to average out and the
> frequency of the gene changes because of the mean selective advantage it
> confers to individuals bearing that allele. Please ignore genetic drift for
> the purpose of this argument. Does any one know of any theoretical
> discussion of this assertion.

Fisher 1930?  Or do you want something readable?

[moderator's note: Hey! I think Fisher 1930 is perfectly readable,
and since it's available in a Dover paperback edition, it's really
cheap, too -- certainly worth tackling. Besides, if _I_ had to wade
through it, YOU should too. - JAH]

You should try a good textbook on quantitative genetics.  Either 
Falconer & McKay or Lynch & Walsh would be a good start (L&W is
big, though)

> I can think of three confounding factors for such as argument.
> 1) Epistatic interactions between the rest of the genome on the coefficent
> of selection are unknown and perhaps unknowable

This is a only problem if there is also linkage disequilibrium.

Also note that for a lot of the genome, the genes are not polymorphic 
(=no variation), and most of the rest of the genome probably have 
negligible epistatic effects.

So, at least the problem is smaller.  :-)

> 2) selection events are insufficiently  uniform. I.e every individuals death
> is a unique event

But that brings you back to drift.  With an infinite number of 
individual deaths, the other effects average out.  With a finite number, 
the difference is drift.

> 3) the combination of the above prevents the normalisation of the data to
> quantify the effect of a particular allele at a particular locus.
> 
No, the first problem was solved by Fisher (but the modern formulation 
is easier to follow), basically you use the additive effect of an 
allele.  See a textbook for the details of what additive means.

> I would have though fisher and others may have dealt with these issues any
> one know of any investigations in to this area
> 
Yep.  Fisher looked at both, in large populations.

Bob

-- 
Bob O'Hara

Rolf Nevanlinna Institute
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/
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