Re: Mitochondrial Eve

Steve Clark (
Wed, 19 May 1999 18:26:03 -0500

I've resisted the temptation to do battle with Kevin on this line of
thought, but enough is enough. His bashing of others over trivial and
sometimes erroneous points (his error) has gone too far.

First of all, different genes MAY have different mutation rates but this is
not necessarily true.

Kevin earlier criticized a list of papers Gordon listed suggesting that
they may be relevant to the discussion. However, Kevin's reply to each
title was that each paper considered "different genes" and hence were
uninformative because, as Kevin claims, different genes have different
mutation rates. This is NOT a given. Then he criticized Gordon for just
basing his interest on the titles of the papers rather than reading them.
Isn't it interesting then that Kevin only critiqued the papers based on
their titles and not content?

Kevin's claim that different alleles of microsatellite loci are different
genes is just crap. Microsatellites are highly repetitive sequences of
dinucleotide or trinucleotide repeats and different alleles simply differ
in the number of repeats of the repetitive sequence. Microsatellites are
not genes. Nevertheless they are heritable and show allelic variation.
Apparently Kevin has a serious problem with the definition of gene.

At 05:38 PM 5/19/99 EDT, wrote:
>In a message dated 5/19/99 12:45:19 PM Mountain Daylight Time,
>> 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.

This is rather circular.

>> 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.

This is not necessarily true. Alleles of a gene do not act like separate
genes and are not inherited like separate genes. They are inherited like
alleles of the same gene. Different alleles of a gene may or may not have
different rates of mutation. This is not a given. Finally, microsatellite
alleles are not genes. They do not encode a protein product.