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From:
Subject: Re: [DNA] MRCA = 800 AD
Date: Tue, 28 Dec 2004 18:09:29 +0000


Thanks Ann and Ken for doing the computations.

Basically I want to be able to tell these chaps something, anything.

It appears that the Y-DNA evidence is consistent with the genealogical evidence. I don't think I can say more than that except to do one more thing. Check Dennis Garvey's R1b pages for the rarity of occurrence for each marker. Clearly if they share a cadre of infrequently seen marker values, this adds more weight to the hypothesis of "somewhat near to Identical, considering the number of generations, By Descent" has validity.

David F.



-------------- Original message --------------

> In a message dated 12/28/04 9:14:36 AM Pacific Standard Time,
> writes:
>
> > Would someone who is more adept at stats than I kindly determine the
> > expected number of mutations in 90 transmissons (45 for each man back to the
> > alleged common ancestor) using both the standard mutation rates (e.g., .028)
> and
> > those arrived at by FTDNA recently for their first two panels. Gracias.
>
> You can plug in various combinations of transmission events, mutation rates,
> and markers into my Mutation Calculator. The output shows the percentage of
> times you would see 0,1,2, etc. mutations if you studied a large number of
> cases.
>
> http://members.aol.com/dnafiler/MutationCalculator.exe
>
> For the "expected" number, the calculation is straightorward -- transmissions
> * markers * mutation rate = 90 * 25 * .0028 = 6.3. (Note you need one more
> zero for your mutation rate.) The Mutation Calculator output will show that six
> mutations is indeed the single most likely outcome (the Maximum Likelihood
> Estimate, MLE) -- but in absolute terms, it's only about 16%. So the statistical
> and the everyday use of the word "expect" is different -- we shouldn't
> "expect" to always see the "expected" value. Five or seven mutations are
> somewhat
> less likely, four or eight mutations still less, and so forth.
>
> Ann Turner - GENEALOGY-DNA List Administrator
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