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Archiver > GENEALOGY-DNA > 2006-03 > 1142333989


From: "Exec" <>
Subject: Fw: [DNA] Re: Ages of S28+ (and S21+)
Date: Tue, 14 Mar 2006 11:59:49 +0100


John,
You are right; i did leave out the likely non-linear expansion aspect, but
(see below) i had not ignored it. My estimates, based on east European
data, suggest that an overall 2.1% is applicable between 20k and 40k
years,
giving an overall straightline equivalent rate of 1.79% over 40k years.

I deliberately avoided introducing the aspect of non-linear expansions,
back mutations, and the effect of population setbacks (death, famine , war
and pestilence, etc) to circumvent debate on these topics, but also when i
tested my theory on east European data, the conclusion was that, even over
37k yrs, the DYS390 =24 reduction rate had only increased to the equivalent
of a linear 1.79% per 1,000 years, viz...
(i) Dennis Garvey predicted in 2002 that the M269 brand of R1b probably
entered Europe about 37.5k yrs ago ( Dennis's range was 35kyrs - 40k).
(ii) In my Russian/Baltic data of about 150 R1b haplotypes, DYS390 is modal
at 24, but is only 32.7% of the R1b sample.

(iii) From (i) and (ii) the simple, linear equivalent of the probable
non-linear change of 67.3% over 37.5k years is 1.79%/1,000 yrs.

Using 1.79% per 1,000 years to calculate the possible age of the Atlantic
subgroup in western Europe (in which DYS390=24 has reduced only by 30.3%)
gives the Atlantic subgroup an age of 17,000 (16,927) ybp, since its
post-LGM recovery. This compares reasonably well with my original
assumption that the Iberian R1b population probably began to recover from
the LGM about 20,000 ybp, allowing some of its population to expand,
eventually, across the 1,200 miles or so to Britain, where archaeology
confirms that some settlements had been established there by 15,000 ybp.I
Thanks fr yr interest.

Alan Foster.
========


> I----- Original Message -----
> From: "John Chandler" <>
> To: <>
> Sent: Sunday, March 12, 2006 11:31 PM
> Subject: Re: [DNA] Re: Ages of S28+ (and S21+)
>
>
> > Alan wrote:
> > > In this scenario, if DYS390 has reduced from anything like 100% being
> > > DYS390=24 (within the founding subgroup) to its current 69.7%, then
the
> > > DYS390 modal has decomposed ( 30.3% in 20,000 yrs) at about 1.52% per
> 1,000
> > > years in the Atlantic region.
> >
> > One thing you're leaving out is the non-linear nature of the decay
> > process. For example, if we take the generation length to be 30
> > years, then there are 667 generations in 20,000 years. Over that
> > time, the frequency of DYS390=24 is falling progressively, so that the
> > decay rate itself is declining, and, not only that, but the amounts of
> > DYS390=23 and DYS390=25 are increasing, and these both lead to a
> > rising rate of replenishment. The long and short of it is that the
> > implied mutation rate in falling to 69.7% in 667 generations is 0.0005
> > per generation, which comes to 2% decay in the last 1,000 years (33
> > generations). Not 1.52%. The larger the total decay, the more
important
> > the effect of this non-linearity.
> >
> > John Chandler
> >
> > ______________________________
>


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