GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2006-09 > 1158245987


From: Jim T <>
Subject: Re: [DNA] Spreadsheet of GDs for kits with 67 marker resultsin Kerchner's R1b project
Date: Thu, 14 Sep 2006 07:59:47 -0700 (PDT)
In-Reply-To: <mailman.9460.1158210627.24100.genealogy-dna@rootsweb.com>


> John Carr wrote:
>
>The average Genetic Distance of this file is roughly 27,
>with a fairly consistent range between 17 and 44. I know
>a genetic distance this large is not considered reliabe due
>to the vast number of possible mutation events that may have
>ocurred. But, if these averages and ranges continue to hold,
>it must be more than randomness. Assuming the average GD
>is a reliable indicator of genetic distance between everyone
>on this list (a bit of a stretch I know, but ...) and using
>the standard average mutation rate, when would most common
> ancestor of the people on this list lived?
>
>John Carr

I suspect that a large majority of people in the spreadsheet are
R1b1c. Some lines will have more mutations than average since
the R1b1c MRCA, some will have fewer. It seems reasonable to
use the average GD of 27 between two people with 67 markers in a
MRCA calculator to estimate the age of R1b1c. The problem is
what to use for the mutation rate. The mutation rate used by
academics for these kind of calculations is very different from
what is observed in father son studies.

FWIW, here is the distribution of average GDs:

20 *
21 *
22 *******
23 **********
24 **********************
25 *****************************
26 *********************
27 ******************************
28 **********************
29 ********************
30 ***********
31 *********
32 ********
33 *****
34 **
35 *


27 is the mode as well as the mean.

Jim Turner

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