Re: rapid variation

GRMorton@aol.com
Sat, 9 Sep 1995 18:34:08 -0400

Walter wrote:
>>
Glenn has a major misunderstanding of chromosomes and ploidy. He mistakes a
haploid genome (e.g. the genome inside a sperm or an unfertilized egg) with
one half (one rail) of a DNA double helix ladder. <<

Walter is correct. I messed that one up. I am sure that it won't be the last
mistake I make in my life either.

Walter wrote:
>>Glenn's "tree ring" analogy is erroneous. Tree rings are deterministic,
they occur at regular intervals, (in theory) exactly one per year in each and
every tree. But mutations are not deterministic, they occur randomly,
stochastically, at an AVERAGE rate. Glenn is wrong for seeking out and
SELECTING those cases with the HIGHEST rate, and using those to represent the
average situation. It's statistically way off base. It's as wrong as
selecting the speediest driver in the nation, and claiming that represents
how fast everyone drives. <<

Walter, you are wrong about the MHC genetics having the highest rates of
mutation. If that is what you are implying here. Page 80 of the Klein,
Takahata, Ayala article in the Dec. 1993 Scientific American states that MHC
genes do not evolve at a faster rate and that this was a shock to the
biological community.

Walter wrote:
>>Glenn's "tree ring" analogy is erroneous. Tree rings are deterministic,
they occur at regular intervals, (in theory) exactly one per year in each and
every tree. But mutations are not deterministic, they occur randomly,
stochastically, at an AVERAGE rate. Glenn is wrong for seeking out and
SELECTING those cases with the HIGHEST rate, and using those to represent the
average situation. It's statistically way off base. It's as wrong as
selecting the speediest driver in the nation, and claiming that represents
how fast everyone drives. <<

If I am not mistaken I believe that what the researchers cited above found
was that MHC mutations occur at the SAME rate as other mutations. This means
that if they show much more diversity than other genes, then they must have
been diverging much longer! In your analogy, if I start a bunch of cars from
New York driving to L.A. and they all can only go a certain AVERAGE speed,
then I can tell when they started by how far they are from New York. If I
find one in Oklahoma, I know from that information and the speed when he
started. That is what the MHC and other genetic diversity data is showing.

Walter wrote:
>>Glenn's calculations began with an AVERAGE mutation rate (of 1e-7), and he
ought to be comparing his the results with the AVERAGE of many, many genes,
not just one gene of his choosing. <<

In the above analogy, if I measure the average distance of the cars, I do not
know when the excercise started. I only know the average time which is
useless.

Watler wrote:

>>The MHC genes do not represent the average gene, nor the median gene. They
do not even seem to represent the tail end of a bell-curve. They are
statistical out-landers who demand special explanation, even from
evolutionists. Evolutionists themselves have described the MHC genes as
having higher than usual mutation rates, and/or gene conversion -- and that
is yet another factor that Glenn's argument did not account. Glenn has no
legitimate basis in selecting these out-landers for his argument<<

As I noted before, there is evidence that MHC genes do not mutate any faster
than other genes. It is true that evolutionists used to beleive that but
they no longer do.

"In the late 1970s Bernhard Arden, Edward K. Wakeland and Klein, all then
working at the Max Planck Institute for Biology in Tubingen, found identical
MHC alleles in two mouse species that had diverged two million years ago.
This quite unexpected finding in species whose MHC diversity at least
matches that of humans implied that the MHC genes did not evolve faster than
other genes.". p. 80 of the previously cited article.

Since this has been known since the late 1970's isn't it time to alter your
opinion of their speed?

glenn