Re: Mitochondrial Eve

Marcio Pie (
Wed, 19 May 1999 17:56:43 -0400 (EDT)

On Wed, 19 May 1999 wrote:

> In a message dated 5/19/99 12:45:19 PM Mountain Daylight Time,
> writes:
> > I must desagree with your arguments in this matter. Genes may have fairly
> > constant mutation rates in the short term, but in the long term genes are
> > modified, and the structural features that maintain the mutation rates
> > may eventually change over time.
> >
> This is a hair-splitting rebutal. Of course if genes change then so can
> their mutation rates, but if they change they are technically no longer the
> same genes they were before they changed. After all, different genes have
> different rates of mutation. What Gordon Simons is talking about are the
> rates of mutation of STABLE genes; ie, genes that do not change. Any gene
> that does not change has a constant rate of mutation; if it changes then its
> rate of mutation may also change, but genes that do not change do not have
> changing rates of mutation.

Please forgive my ignorance, but I still cannot understand how a gene can
CHANGE and still be exactly the same gene. It seems to me that you can't
loose here.

> >
> > Alleles at the same microsatellite locus are different genes??? This is
> > new to me!!
> >
> Excellent. Then you have learned something new. Alleles are genes that
> produce the same (or essentially the same) protein product that differ only
> by slight mutations yet can be differentiated and separated by Mendelian
> genetics. The fact that they are very similar is irrelevant; they act like
> separate genes and fundamentally they are different genes, hence each can
> have its own rate of mutation.

The definition that I've learned and that is in Futuyma's textbook says:

"Allele: One of the several forms of the same gene, presumably differing
by mutation of the DNA sequence, and capable of segregating as a unit
Mendelian factor. ... ...DNA sequence variants, that may differ at
several or many sites, are usually called haplotypes."

I've never read a paper where the authors referred to different haplotypes
of the same gene as different "genes." Since this is not my area of
expertise (I'm a behavioral ecologist), I recognize that I may be wrong.