Glenn writes:
>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.
Glenn says MHC genes "do not evolve at a faster rate" than other genes. He
is paraphrasing from an evolutionary article. One should be careful when
doing that because such articles frequently contain unstated hidden
assumptions and wording that can be ambiguous when taken out of context.
Glenn's example is such a case because the article ASSUMES that MHC genes
have a long transformational history between widely diverse organisms. It
assumes large-scale evolution (such as between rodent-like organisms and
man), and evolutionary timescales, then it calculates the rates of evolution
based on those assumptions. In other words, buried deep within Glenn's
argument, is the ASSUMPTION of the very thing he is arguing for. He argues
against creation and for evolution, but those things are silently assumed
deep within the "data" he brings to the table.
Glenn's genetic variation argument is explicitly about variation within a
species. To make that argument, the behavior of genes (such as MHC genes)
WITHIN A SPECIES must be evaluated outside of any assumptions about
large-scale evolution. In short, Glenn's citation about the
macroevolutionary behavior of MHC genes is irrelevant in our debate.
******
>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.
As I said above, the researchers assume large-scale evolution and
evolutionary timescales and (based on the known DNA sequence differences)
they then calculate the mutation rate that would be required to make
macroevolution plausible. The data resulting from that calculation cannot
be applied in a creation model. Glenn's "data" assumes as true the very
thing that he is arguing for.
******
>This means that if [MHC genes] show much more diversity than other
>genes, then they must have been diverging much longer!
Glenn is contradicting himself. His argument assumes a population
bottleneck 200 generations ago, and since then all genes have been diverging
THE SAME AMOUNT OF TIME. That model cannot possibly conclude that MHC genes
"must have been diverging much longer" than other genes.
To use Glenn's "tree rings" analogy. Glenn wants to date the age of the
forest, and his model indicates that every tree in the forest is the same
age. Glenn then counts tree rings in all the trees and SELECTS the tree
with the most rings as the age of the entire forest. Glenn's selection of
that tree is suspect -- it needs justification and explanation. ***With the
proper adjustments to the model,*** that needed justification might be
supplied. But Glenn hasn't done it.
Glenn's selection of the MHC genes is particularly suspect, as these genes
are currently a matter of controversy (including their mutation rate and
gene conversion). As I said above, those controversies cannot be settled
here by calculations derived from macroevolutionary assumptions about MHC
genes. Such calculations are irrelevant in a debate about the creation model.
>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 believe 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.
Once again Glenn is using macroevolutionary assumptions to calculate the
mutation rate of MHC genes. He concludes from those calculations that MHC
genes "do not mutate any faster than other genes." That calculation and its
conclusion are irrelevant in our debate because they assume macroevolution,
the very thing Glenn is arguing for.
Most genes have one to five alleles -- that's FEWER than Glenn's original
population could have easily possessed. The MHC genes are distinct
out-landers, having a diversity far above what could be statistically
expected. The MHC genes cannot plausibly be the tail of bell-curve, instead
they require special explanation. Even evolutionists saw this and
concluded, at the time, that MHC genes must have a higher than usual
mutation rate (and/or gene conversion). That conclusion is not overturned
by recent calculations derived from macroevolutionary assumptions. If those
calculations raise a contradiction, then it is the macroevolutionary
assumptions themselves that are called into question.
Walter ReMine
P.O. Box 28006
Saint Paul, MN 55128