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Subject: Re: From Tony Frudakis RE: [DNA] Cecelia's Mother's DNAPrint 2.0 Results
Date: Thu, 4 Sep 2003 13:13:36 EDT
In a message dated 09/03/03 1:17:21 PM Pacific Daylight Time,
writes:
> This is the first time, in all the correspondence from Dr. Frudakis,
> where he says that the first confidence interval ("the 2 fold space," as
> he calls it, here) is a "better answer" than the MLE. So, everybody get
> out your red crayon and color in the inside of the arc of the first
> confidence ring on your triangle plots. (And, don't forget to project
> and extend the arc of the ring outside of the triangle!) Somewhere (and
> it could be anywhere) within this giant red blotch are your most likely
> ancestral percentages (that is, before possible systematic error is
> figured in). Would you have paid for these test results, if you really
> understood that this would be your answer?
To be fair, the "2 fold" space has been described in the manual from day one.
It's just that the statistical concept of "Maximum Likelihood Estimate"
sounds more impressive and more precise than you would guess from everyday usage of
those terms.
I see some analogies to the uncertainty that goes with the MRCA (Most Recent
Common Ancestor) calculations for Y-chromosome testing. It would certainly be
nice if we could say your MRCA lived exactly 5 or 8 or 13 generations ago, but
the best we can do is to say the results are (or are not) consistent with an
ancestor who lived in a genealogical time frame. Yet I often see people
rejoicing about a 25-marker match which "proves" that their MRCA lived within the
last seven generations.
Ann Turner - GENEALOGY-DNA List Administrator
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