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Archiver > GENEALOGY-DNA > 2007-03 > 1172787986


From: "Alfred A. Aburto Jr." <>
Subject: Re: [DNA] Challenge to YDNA J Gurus
Date: Thu, 01 Mar 2007 14:26:26 -0800
References: <001901c75c2a$8ba69340$6400a8c0@Ken1>
In-Reply-To: <001901c75c2a$8ba69340$6400a8c0@Ken1>


Ken,
I have just completed with the histograms of the J1 & J2 data I have
(maximum of 2748 J haplotypes with varying degrees of tested markers).
This includes 78 markers from Ysearch, DNAH, SMGF, and various data
published in technical articles. I haven't done your matrix though. I
just calculated the GD between J1 and J2 using all 78 (fast & slow)
markers. The GD between J1 & J2 is 55 WRT 78 markers which gives a TMRCA
of about 406 generations assuming a mutation rate of 0.002, which at 30
years per generation is about 12171 years between J1 and J2. The worst
"offender" is the "slow" markers DYS413a,b (!!), showing a GD of 9
between J1 and J2 alone... I'll report back with the GD of the slow
markers (including 413a,b) in a bit ...

I am currently going through the database, since FTDNA estimates alot
(most) J2's as just J2(!), and I'm using Whit's fine program to separate
J2 into J2a and J2b as a minimum. However, I am finding quite a few
J2a1k's! Bonnie is right that J2a1k is a significant population of J2.
I'm slow at doing things, but, well, eventually, the tortoise will make
it home :-)
Al


> Ken Nordtvedt wrote:

>It seems that the J specialists may have enough 67 marker haplotypes now to have determined 67 marker modal haplotypes for a number of robustly distinct clades in y-haplogroup J, including in J1 and in J2 (I call such haplotypes "founders' haplotypes").
>
>If so, I believe it would be of interest to see a genetic distance matrix between those several founders' haplotypes.
>
>It is important, I believe, to with discipline pick the 30 or so slowest mutating markers from the 67 (using Chandler's rates, for example), paying no regard to which of these slow markers are particularly useful or not in identifying the separate clades. Paying such attention will bias the marker selection and increase the apparent time between founders. Picking the slow markers minimizes occurrences of unseen back mutations having taken place in the generational strings between the founders.
>
>This matrix of GDs will give an overview sense for the time periods which occured between the existences of the founders relative to haplogroup breakup times.
>
>Rough rule of thumb is to divide the GD by twice the sum of mutation rates for the 30 or so slow markers you chose to use. This is a characteristic time in generations between a split up of the parent clade to the times of the founders for the subclades.
>
>Most of us sense that J is a particularly old haplogroup by the standards of the other haplogroups commonly dealt with in Europe. It would be interesting to see the time scales that emerge from the GD matrix. Maybe someone has done this already, and I have just missed it?
>
>See http://knordtvedt.home.bresnan.net and then file FoundersTree for such a tree constructed for y-haplogroup I.
>
>
>
>Ken
>
>


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