Archiver > GENEALOGY-DNA > 2010-03 > 1269883623

From: "O. W. Odom" <>
Subject: Re: [DNA] Family Finder Test
Date: Mon, 29 Mar 2010 12:32:22 -0500
References: <><>
In-Reply-To: <>

Considering a given set of 44 autosomal chromosomes (22 from each parent)
and excluding crossovers, the chance of a second set of 44
autosomal chromosomes having no match with the first set is 1/2(exp)44, or
about 1 out of 17.6 trillion, so I think we could say this is vanishingly
small, and crossing over would reduce the odds dramatically more.


At 11:24 AM 3/29/2010, Stephen wrote:
>A question I've wondered about for some time is the following:
>We know that the mean amount of nuclear DNA shared between two full siblings
>is 50% of the total. What is the variance?
>I imagine this depends considerably on crossover frequencies, etc. and thus
>is not a completely straightforward calculation but surely there must be
>estimates, especially now that we can compare shared segments! In your post
>you allude to a small but nonzero probability of no shared autosomal DNA
>between siblings, so presumably the variance is high enough to not
>completely exclude that.

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