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Archiver > GENEALOGY-DNA > 2005-12 > 1134803354


From: (John Chandler)
Subject: Re: [DNA] RE: Are you missing the Geno boat?
Date: Sat, 17 Dec 2005 02:09:14 -0500 (EST)
References: <20051216194215.90845.qmail@web81807.mail.mud.yahoo.com>
In-Reply-To: <20051216194215.90845.qmail@web81807.mail.mud.yahoo.com> (messagefrom Robert Stafford on Fri, 16 Dec 2005 11:42:15 -0800 (PST))


Bob wrote:
> I have never been able to reconcile the numbers. For example, they
> refer to 50,357 Y records, instead of haplotypes.. What do they
> define as a record? Is there just one record for each person or 1
> record for Y-STR results, another for SNP results and another for
> MTDNA results.

As I read the announcement, it says to me there are 50,357 persons with
Y-DNA test results and 14,981 persons with mtDNA test results. Some of
those are the same persons, of course.

> They don't quote a number for 37-marker haplotypes. Is it the
> difference between 25 and 12 results and the number above?

No. They are talking about *distinct* haplotypes. The figure of
14,886 distinct 12-marker haplotypes tells me that, on average,
a person can expect to have 2.5 matches in the database at 12
markers. Of course, there is probably a very skewed distribution
of matches, and it may be extremely rare to have 2 or 3 matches,
instead of none or 50. In any case, they don't say how many of
the Y records include 25 markers, so it isn't possible from this
announcement to calculate the expected number of matches at 25,
but experience indicates that it's much smaller.

John Chandler

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