GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2002-11 > 1037563620
From: "John F. Chandler" <>
Subject: Re: [DNA] MRCA calculations
Date: Sun, 17 Nov 2002 15:07 EST
In-Reply-To: DNACousins@aol.com message <firstname.lastname@example.org> of Sun, 17 Nov 2002 09:24:47 -0700
> I checked your formula against Bruce Walsh's tables for 20 and 50 markers. It
> looks like your formula underestimates slightly, more and more as D
> increases. But I think this would be a good ball-park formula for cases where
> we don't have any tables.
Actually, my formula gives an OVERestimate. I think Walsh's tables
give values for the number of loci that match vs do not match. Thus,
if you read his table to get the time for n=20 and k=19, you are getting
a superposition of cases with D=1, D=2, D=3, etc., where only one locus
is affected. This superposition increasingly makes the two quantities
diverge as k decreases and D increases.
|Re: [DNA] MRCA calculations by "John F. Chandler" <>|