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From: "Lancaster-Boon" <>
Subject: [DNA] TMRCA assessments
Date: Tue, 16 Feb 2010 07:57:12 +0100


Dear Anatole

Anatole to Richard Stafford:-
>The difference between "parallel mutations" and back mutations is a
fundamental one, in my view. "Parallel mutations" are trivial mutations, can
happen in any generation, and should be counted as anything else. Back
mutations take a long time to make a noticeable contribution, because they
are in a way similar - statistically - with two-step mutations.

OK, so parallel mutations are more common than back mutations.

But if by trivial you mean that they simply "should be counted as anything
else" there is a problem.
How do you count them?
First you look at the haplotype tree right?
How do you make the haplotype tree?
The computer or whatever, uses a human-made method, and looks at which
markers are the same?

So how does the method distinguish parallel mutations from being in the same
branch?
It can not normally do it.

Also any method at all which involves counting differences from modals etc
will be fooled by parallel mutations.

What am I missing?

Best Regards
Andrew


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