The Fool wrote:
From: David Hobby <[EMAIL PROTECTED]>
...
I think your math is off. Otherwise there would be a much more even
distribution of alleles.
No, there doesn't have to be much gene flow at all for
everyone to have a recent common ancestor. This is the
gist of Alberto's argument that "one f--k can infect a
tribe". All it takes is a little bit of gene flow.
1st generation children would have about 23 chromosomes from lone
invader-parent.
2nd gen would have on average 11-12 chromosomes.
3rd gen would have on average 6 chromosomes.
4th gen would have on average 3 chromosomes.
5th gen would have on average 1-2 chromosomes.
6th gen would on average have 1 or less chromosomes.
This ignores selection of course.
At an average of 2 surviving children per generation, there would at
generation 6 be about 64 decendents with aproximately 1 chromosome. The Lone
Invader Parent had 46 chromosomes, as compared to about 64 individual
surviving chomosomes in his descendents, most of them duplicates. (This
ignores inbreeding, which is endemicic in certain populations, mostly arabic,
that for reasons of maintaining property rights, marry first cousins).
An Actual Inverse Square-Law as opposed to Alberto's Sqaure-Law.
Fool--
So it sounds like we all agree on the broad outline.
If you have a tribe of N people and one invader, then
the "invader's genes" would start with a frequency of
1/N. Barring selection, the frequency would stay at
about that level. Over generations, there is a roughly
exponential increase in the number of the invader's
descendants, and a matching exponential decrease in
how many of his genes they each have.
---David
Khan!
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