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Archiver > GENEALOGY-DNA > 2002-08 > 1030633995


From: "JECrain" <>
Subject: Re: [DNA] How Specific is 12 marker test
Date: Thu, 29 Aug 2002 10:13:15 -0500
References: <5.1.0.14.0.20020828144332.0572e120@mail.verizon.net>


If two or more individuals in a study match on all 12 markers and they share
a surname and all live in the Southern States of the USA, what is considered
their probability of sharing a common ancestor in the last 300+ years. The
sequence shared is said to be a 90% probability of being Amerindian. So how
far back in generations does this point to a MRCA? Thanks.

Janet Crain


----- Original Message -----
From: "John S Walden" <>
To: <>
Sent: Wednesday, August 28, 2002 2:02 PM
Subject: Re: [DNA] How Specific is 12 marker test


> At 08:14 PM 8/28/2002 +0200, you wrote:
> >I would be interested in hearing what other list members think about
thes=
> >e results. I personally was surprised that the additional marker
upgrade=
> > didn't lead to even finer discrimination among cases - more people
staye=
> >d "closely related" at the 25-marker step than I might have expected
befo=
> >re looking at the data.
>
>
> Thanks for plowing through the studies to get the data.
> Here is some of what I got out of the analysis
>
> First, it looks like applying thought to the process of upgrade or not
does
> work.
>
> Second, A 12/12 match gives about an 80% assurance of relatedness.
> Thus if one is looking for that 95% confidence, that quite often comes up
> in statistics,
> then the 23 or 25 marker test will be required.
>
> Third, A match of 10 out of 12 should be considered as NOT a match.
> John W
>
> ______________________________


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