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Archiver > GENEALOGY-DNA > 2007-07 > 1183354344


From: Didier Vernade <>
Subject: [DNA] R1b1c7 as a calibration tool
Date: Mon, 2 Jul 2007 07:32:24 +0200
References: <738632.10095.qm@web83718.mail.sp1.yahoo.com>
In-Reply-To: <738632.10095.qm@web83718.mail.sp1.yahoo.com>


Dear list,

The following links allow you to download files for R1b subclades with a color
code to visualize genetic distance.
http://www.megaupload.com/?d=TFSLPAKI for R1b1c7
http://www.megaupload.com/?d=C9B2UQMR for R1b1c6
http://www.megaupload.com/?d=6P45XQAC R1b1c6 (a few modifications)
http://www.megaupload.com/?d=B8J945EO for R1b1c9

I hope you'll find them usefull. I used the R1b1c7 file to find the genetic
distance on 31 markers (the 37 marker set from FTDNA without 464 and CDY).
For each haplotype the genetic distance to the founder (in pale yellow) is
counted.
Here is the distribution found for R1b1c7 :
012345678
5142939493119152

It's a nice unimodal distribution with a neat peak for 4.

My believe is that " Neill of the nine hostage" or rather one of his close
ancestor may be is really the founder. In the following I suppose that the
founder lived 1700 years ago. This fairly precise dating can be used to get
an estimate of TMRCA for other groups and the advantage is that no other
assumption is to be made on the average mutation rate per generation that it
stayed the same between "R1b1c7" time and , for example, "R1b1c6" time. In
addition, no guess on the generation time is needed, assuming again that it
didn't change between "R1b1c7" time and the time of the group studied.
As an example I applied it to R1b1c6. The distribution for R1b1c6 is :
2345678910
113364252

and there is one at 11 and one at 12.
The figures are low but it looks like a bi-modal distribution with a first
peak at 6 and a possible lower peak at 9. Here is how a TMRCA can be found
for each of these 2 peaks.

There is proportionality between the time and the genetic distance for the 31
markers studied. Therefore, the time for the first peak is :

T = 1700 x 6 / 4 = 2550 taking round values for the peaks. So that would
mean that a founder lived at iron age ( 550 bc ) for R1b1c6.

For the second peak we get :

T = 1700 x 9 / 4 =3825 again for a rough estimate with round values. This
could mean that the initial founder lived at bronze age and among his lineage
there was an important "second burst" at iron age. This is merely an example
of the method apply. As more data will be available I expect it to be a very
convenient way to estimate TMRCA.

As for the value "1700" I took Conn as the possible real founder. The "burst"
is undoubtedly due to Neill of the nine hostage but he may have kept the same
haplotype values as a recent ancestor such as Conn. This, anyway may even be
tested as data on R1b1c7 group are increasing.
I don't discuss the other haplogroups here. It seems that they are older.
One advantage of this method is to allow identification of multiple peaks in
the genetic distance distribution.

Didier


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