Re: Floyd, This Is My Repsonse

On Fri, 28 Nov 2003 04:57:51 +0000 (UTC),
[EMAIL PROTECTED] (Nowhere Man) did some sarious
thank'n and scribbled:

>This is a common mistake that people who believe in evolution make so
>do not feel bad about it. You ask what would stop these helpful
>mutations from happening. 

Your argument is weak if not false. Most mammals have a
number of mechanisms with promote the mutation process.
For one the DNA polymerases are less than perfect and make
mistakes, more-so in humans than other species that have
almost perfect fidelity in replication. Therefore there is
not perfect selection on polymerase fidelity. 
 
Secondarily there is a very active and rapid process for
recombining mutations into new variants.

Read Parham and Ohta, Science 1996 or Watkins. Critical
Reviews in Immunology 1995. 

The mammalian replicative process is not entirely passive
with regard to creating mutations, without considering gene
conversion as discussed by Parham and Ohta, simply consider
that each generation there are approximately 2 recombination
events on each chromosome for a total of 90 recombination
events per generation per individual. 

>The real question is not what would stop
>them but what would cause them.

If you stopped them within a few hundred thousand years the
species would probably die off. Recombination keeps the
population healthy by having certain individuals with
multiple disgenic traits that perish or are unlikely to
reproduce favoring individuals with the best combinations.

> If you want to claim that mutations
>can cause new features than you have to find evidence for your claim.

Right, gene conversion in south america

The appearance of approximately 30 new HLA B and C
phenotypes over the last 15,000 years that are both
functionally different and resulting from recombination.
These new allelotypes are most likely the result of
constrictions in the earliest immigrants couple with disease
selection in south america. The frequency and abundance of
new haplotypes relative to the founding populations in
northwestern pacific suggest that selection changed as
people migrated and that this positively selected for
nascent DNA allelotypes in south america. As a result one
should conclude that at some loci 15,000 years is a
sufficient time for rapid evolution of positively selective
traits. 

See references above. 

>I personally suggest that you save some your time because I have
>looked myself and there has never been a benificial mutation that has
>been observed. Mutations only do harm. There is evidence for that. If
>you want to say they can cause new constructions then you need to
>provide some  evidence for that.

See above, you don't know what you are looking for. 

>Yes I agreed that there is change is all living things but I did not
>say that it was caused by mutations.

See above, SNPs provide a basis rapid changes occur with
gene conversion and recombination. 

> That would not be reasonable. The
>changes are built into the life form's original designs. That is the
>only reasonable explanation

Wrong, unless Noah personally carried people from mt. ararat
to south america, dropped them off and came back (not to
mention hugely erroneous timing). 

>  if you think about it.

Obviously you haven't thought about it because you are
wrong. 

Other examples of genetic change that has been beneficial:

1. Reduction of glutin Upper GI susceptibility in agrarian
societies that grow wheat, persistence of susceptibility in
agrarian societies that do not. 

2. Reduction in type II diabetes in societies where fat and 
carbohydrate abundance were cyclical.

3. Lactose tolerance in milk consuming societies. West
africa and northwestern europe. 
(results from an extension into adulthood the enzyme that
allows lactose digestion)

4. Alcohol dehydrogenase and metabolism in societies where 
alcohol drinking traditions have developed. 

There are many changes in beneficial genes in humans that
have occurred in the last few thousand years, most of these
are based on genetic variants in place; however in the case
of the HLA A,B,C types in south america 15,000 years ago
these variants did not exist and came to exist as a result
of nascent recombinant allelotypes and positive selection.