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Archiver > GENEALOGY-DNA > 2011-11 > 1320889037


From: Terry <>
Subject: Re: [DNA] IBD segment common ancestor age calculation
Date: Thu, 10 Nov 2011 12:37:17 +1100
References: <1320835162.21575.YahooMailNeo@web29520.mail.ird.yahoo.com><CACPdyDmVMdZ6DS3ttFmd9DLUdKfRpKerbAnsEwPGyWOSXSGF-g@mail.gmail.com><CAJet0toQO0NwOUsDjirY2WGTUY0kTMM8YeUgt==2J2vRVeAqQw@mail.gmail.com>
In-Reply-To: <CAJet0toQO0NwOUsDjirY2WGTUY0kTMM8YeUgt==2J2vRVeAqQw@mail.gmail.com>


Paul,

The table does appear to say that if two people have a tMRCA of say 4
generations, then they are likely to have an average size block of 9 cM in
common. Is that an unreasonable number? Perhaps the table is quoted wrong.
Or perhaps the reverse statement is not true.

Terry


On Thu, Nov 10, 2011 at 11:57 AM, Paul Wright <>wrote:

> If anyone thinks MOST 5 cM autosomal matches are related within 7
> generations and 9 cM matches are within 4 generations, they are most likely
> dilusional.
>
>
>
> On Wed, Nov 9, 2011 at 6:14 PM, Terry <> wrote:
>
> > Anders,
> >
> > In CeCe's blog on the Family Tree DNA's Conference on Genetic Genealogy -
> > see
> >
> >
> >
> http://www.yourgeneticgenealogist.com/2011/11/family-tree-dnas-7th-international.html
> >
> > there is quoted a table by Bruce Walsh, that says amongst other things,
> > that a 5 cM match between two people would likely correspond to a 7
> > generations ago TMRCA, and a 9 cM match would likely correspond to a 4
> > generations ago TMRCA etc.
> >
> > Not certain if that is what you were asking.
> >
> > Terry
> >
>


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