Re: Rapid genetic variation

Steve Clark (ssclark@facstaff.wisc.edu)
Sun, 20 Aug 1995 14:50:11 -0500

Glenn writes:

>Abstract: Walter's argument is shown to be based upon a faulty definition of
>what an allele is.
>
>I wrote:
>>>But Noah and his family did not start with two million copies of a gene at
>least as far as reproduction is concerned. They started with 10 alleles max
>at each location ...<<
>
>Walter replied:
>>Fine, for the sake of discussion let's freeze the genetics right there --
>and allow NO MORE MUTATIONS. Glenn allows that the population contains 10
>alleles maximum for a given gene. How many genes are in the human genome?
>Here I will use the evolutionists' figure of 100,000 genes to code for the
>human body. (I think it a serious underestimate on their part, it amounts
>to merely 2.9 percent of the DNA in a human sperm.) Thus, that small
>population contains roughly 10 x 100,000 = ONE MILLION different alleles.<<
>
Glenn is correct that this is a misleading calculation that probably
originates in a faulty conception of what an allele is.

> "Each gene occupies a specific poosition on a chromosome, called the
>gene *locus* (*loci*, plural). All allelic forms of a gene therefore are
>found at corresponding positions on genetically similar (*homologous*)
>chromosomes."

THus, an allele is a different form of the same gene. Any individual can
carry, at most, two alleles, but the total population (gene pool) may
contain several different alleles, each fixed in the gene pool according to
the Hardy-Weinberg equation.

>What you calculated above is the total number of GENES in the population of
>10 people. That is not at all the same as the number of alleles that same
>population could have. The maximum number of alleles in the 5 independent
>people on the ark was 10.

Steve
____________________________________________________________________________
Steven S. Clark, Ph.D. Phone: (608) 263-9137
Associate Professor FAX: (608) 263-4226
Dept. of Human Oncology and email: ssclark@facstaff.wisc.edu
UW Comprehensive Cancer Ctr
University of Wisconsin "To disdain philosophy is really to
Madison, WI 53792 be a philosopher." Blaise Pascal
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