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Archiver > GENEALOGY-DNA > 2010-03 > 1269797868


From: Vincent Vizachero <>
Subject: Re: [DNA] 23andme cousin results
Date: Sun, 28 Mar 2010 13:42:25 -0400
References: <CCC182DA-E426-430A-BA37-355BD4D5E8AD@earthlink.net><ea3bd9561003272128k3b567d83y190aeb937b77803b@mail.gmail.com><253CFBB8-15B8-4B84-81E5-A4F86DEEC8D7@earthlink.net><ea3bd9561003280921v52a58139o5e8c730e640c5c7f@mail.gmail.com><00d901cace95$a4b8bda0$5e82af48@Ken1><CB6050F2-F6A2-4324-A8E2-060B8829AD1E@earthlink.net>
In-Reply-To: <CB6050F2-F6A2-4324-A8E2-060B8829AD1E@earthlink.net>


Actually, the explanation for this is that two parents have genomes
that are something more than 0% identical to each other. In fact,
even complete strangers are about 65% to 75% identical for the SNPs
commonly tested.

So, if roughly 50% of my DNA comes from my father (that part must
match 100%) and 50% comes from my mother (and my mother is, say, a 70%
match to my dad given that they are genetic "strangers") then I will
match ((.5*100%)+(.5*70%))= 85% with my father.

VV


On Mar 28, 2010, at 1:31 PM, John Carr wrote:

> Perhaps this male recombination bias David mentioned explains why
> parent to child shared results and sibling shared results are
> consistently around 84% rather than the 50% that is offered as the
> expected shared result.


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