GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2007-07 > 1184240096


From: "Joe Knapp" <>
Subject: Re: [DNA] Help please with marker 458
Date: Thu, 12 Jul 2007 07:34:56 -0400
References: <008701c7b415$794b0120$2401a8c0@your447023ae6b><REME20070705181857@alum.mit.edu><a81622ac0707051724y16754956obfb853b6686e74ed@mail.gmail.com><REME20070707152459@alum.mit.edu><a81622ac0707071304x11373a0en3b0b4e52a7b2e3c@mail.gmail.com><REME20070707183721@alum.mit.edu><a81622ac0707071637o34a3421dr36660529da9f75a4@mail.gmail.com><REME20070709202718@alum.mit.edu><a81622ac0707092003u290a5dd4s96c4a87a62fe3230@mail.gmail.com><REME20070711175004@alum.mit.edu>
In-Reply-To: <REME20070711175004@alum.mit.edu>


On 7/11/07, John Chandler <> wrote:
> Nonethless, your FFT showed what looked like significant power in
> the frequencies of interest. You apparently need to do some
> smoothing to see the oscillations.

What are the frequencies of interest? There's power at the lower
frequencies mostly due to the initial spike in birth rate as the
population builds up to the steady state, plus of course the "DC"
term.

> > I'll think about what I need to do to the program to do what you
> > suggest re an expanding population. One issue is that I'm limited by
> > memory concerns to about 2,500,000 people total in the simulation, so
> > an exponentially increasing population will hit that limit pretty
> > quick.
>
> Yes, that could be problem unless you pick the expansion rate very
> precisely.

Well then, how much does the exponential constant matter? A flat
population has a constant of 0. Would a tiny growth rate of 0.001/gen
make any difference in the result? I.e., at what point does is the
growth rate large enough to show the effect you want?

> > BTW, re decescendants of the original population, as far as haplotypes
> > go anyway, the founding haplotype at least is still the MRCA at the
> > end of the run.
>
> I'm not sure what you mean by MRCA here. In the 10-tribe case, there
> is obviously not any common ancestor at all, and my suspicion is that,
> even in the one-tribe case, there are many members of the original
> population who still have living male-line descendants after 10,000
> years, but I was hoping you could give a definitive answer for the
> relative numbers in these two cases.

I mean the MRCA where "ancestor" is along the chain of paternal
haplotypes, not individuals per se. So the original universal
haplotype is the founding "ancestor."

As for descendants of individuals, given the initial population of 500
males, here are the only ones having any male descendants at the end
of the 10,000-year run:

10-tribe case:

male#/descendants
36 486
45 526
78 867
125 142
324 949
338 492
369 489
408 6
450 498
479 523

1-tribe case:

male#/descendants
3 343
120 1343
125 172
131 565
141 412
146 15
150 501
187 667
315 248
469 637

Joe

This thread: