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Archiver > GENEALOGY-DNA > 2010-03 > 1268603223


From: (John Chandler)
Subject: Re: [DNA] Number of matches for WAMH in FTDNA database
Date: Sun, 14 Mar 2010 17:47:03 -0400
References: <03a801cac3ab$a0eef800$e2cce800$@org><B27D61E723904037862A4DD2CEF03097@HP><9D479DCC0A57466FB0ACFA8857D0730A@HP><fef9eee41003141352ja1cdd96ga8d6d240c9039791@mail.gmail.com>
In-Reply-To: <fef9eee41003141352ja1cdd96ga8d6d240c9039791@mail.gmail.com>(message from John S Walden on Sun, 14 Mar 2010 16:52:52 -0400)


John wrote:
> I have an Adams man with (only) 12 markers and yes he get th 2058
>
> But then FTDNA report only 22 matches at GD of 1
> those look to be restricted to the Adams project

That seems to be true (and sensible). I have often noticed that
project members who elect to compare against the entire FTDNA customer
database typically get a list of 12-marker exact matches with a
diversity of surnames, but the corresponding list of one-step-off
near-matches contains only the member's same surname. Since the
95% confidence interval of the TMRCA estimate for a one-step-off
near-match goes back about 4500 years, the field of impossible-to-
prove relatives with GD of 1 would be expected to overwhelm that
second list without the extra restriction of having the same
surname.

John Chandler


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