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Archiver > GENEALOGY-DNA > 2004-05 > 1085790366


From: "Debby Reagan" <>
Subject: Re: [DNA] 50% Probability of relationship
Date: Fri, 28 May 2004 20:26:06 -0400 (Eastern Daylight Time)
References: <REME20040528200031@alum.mit.edu>


I wrote:
> Let's see... To get that level of likelihood would require 173
> markers (assuming 0.002 average rate). Extrapolating from the
> 37-marker test, the price would be about $900.

Oops. I neglected to divide by two for the two-way comparison.
Ann's answer of 87 is the right one. That drops the price to a
low, low $475. The formula, by the way, is -ln(1-p)/(2*r*G),
where p is the desired probability (0.75 in this case), r is the
average mutation rate, and G is the number of generations.

John Chandler
***********************
Ok, question..... in mtDNA the markers usually tested
is higher on the onset...... average of 72.
That's 6 times higher than the 12 for the Y.....
do we follow the same theory for the mtDNA only times
the 173 requirement by 6?
If not.... than how could we do the needed caculation for
mtDNA?

Debby Reagan


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