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Archiver > GENEALOGY-DNA > 2005-09 > 1127418528


From: "David F Reynolds" <>
Subject: TMRCA calculation (was re: Felstead TMRCA, hg E3b)
Date: Thu, 22 Sep 2005 12:48:48 -0700
References: <380-220059220214337977@M2W087.mail2web.com> <43308839.6020402@dna-fingerprint.com> <REME20050920182157@alum.mit.edu> <op.sxfa9wsxpqnhvj@pablo> <009001c5be39$39effe50$0100a8c0@chrissam> <op.sxfdbclzpqnhvj@pablo> <00c101c5be3e$424f7300$0100a8c0@chrissam> <001c01c5beb5$a6d62fe0$0100a8c0@chrissam> <op.sxg1kudbpqnhvj@pablo> <003e01c5bf02$b79062e0$0100a8c0@chrissam> <op.sxg849xapqnhvj@pablo> <001801c5bfa2$3d101b00$0100a8c0@chrissam> <op.sxio70hnpqnhvj@pablo> <000a01c5bfa9$5e4beea0$71509045@Ken1>
In-Reply-To: <000a01c5bfa9$5e4beea0$71509045@Ken1>


On Thu, 22 Sep 2005 12:11:00 -0700, Ken Nordtvedt <> wrote:

> But the rate to be used in a TMRCA is the AVERAGE rate for all the markers
> present in the haplotypes being compared. The individual rate for the
> marker or markers seen to have mutated are not to be singled out. The only
> thing that the individual rates is relevant to is how relatively often,
> after lookking at many cases, you should see the different markers being the
> ones that have mutated. In other words, you should see more cases of the
> fast markers having mutated than the slow ones.

How does that reconcile with the statement below from Bruce Walsh, which I read to mean that a single mutation rate is used for convenience? (I'm not quibbling here, just trying to make sure I understand a complicated topic. :) --david

http://nitro.biosci.arizona.edu/ftdna/models.html#Mutation
It is likely that mutation rates differ at microsatellites. Again, if we could find those with the highest mutation rates, these will provide the most information. Since this information is still unresolved, for a first pass, we will assume all microsatellite markers have the same rate (as information on rate differences becomes available, the calculator will be updated to allow for marker-specific differences).

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