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Archiver > GENEALOGY-DNA > 2010-02 > 1265032930


From: John Lerch <>
Subject: [DNA] re GD vs TMRCA
Date: Mon, 1 Feb 2010 6:02:10 -0800


You forgot to mention how many markers you were looking at. E.G. A distance of 4 in 1 generation for a 12 marker profile is absurd.

Sandy P wrote
Much work has been done on the estimation of TMRCA's between pairs of
haplotypes but I've not come across anything that addresses the question of
analysing genetic distances for given TMRCA's. That could simply be because
I don't read very widely.

Whatever the reason, for my own interest, as well as hopefully for the
interest of anyone interested in deep genealogy, I've had a look at this.
The idea is to address for example the following question : If two families
are believed by traditional genealogy to have had a common ancestor say 30
generations ago, what genetic distance would one expect today between
members of the two different families?

The following table gives a partial answer to that question.

TMRCAMean GD

10.44
20.88
31.35


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