Archiver > GENEALOGY-DNA > 2003-11 > 1069278531

From: "Nicholas Penington" <>
Subject: [DNA] Mutation rate and distant ancestors
Date: Wed, 19 Nov 2003 16:48:51 -0500

I assume Relative genetics is still using the mutation rate for
one marker of 0.004 (2 mutations in 500 years rather than 1). The reason I
ask is that with all the uncertainty in the mutation rate of markers
385a,b,439,458,459a&b 449 and the 4 markers 464a,b,c&d it seems as if
0.004 might eventually turn out to be about right when one is using a
mixture of fast and slow mutators?
This is suddenly important for me since I have just found someone
who came within 9 mutations of me on 25 markers but 8 of these are in fast
movers (three of them two-step jumps) BUT he shares my surname! The
closest anyone has come to me so far is 6 mutations off but they never
share my surname. This is not surprising by the way since I am the first
to come to the US and my family back in the UK are not at all interested
in genealogy and won't get tested even if I pay!
I have done the estimates of MRCA, squaring the differences etc
but If we use the 0.002 mutation rate and assume 62 transmission events
and Ann's calculator (assuming a relationship occurred at the beginning of
surname adoption) the chance of this guy being related to me in the male
line is about 4.2% (adding the probability of 9,10,11 etc mutations) so we
conclude no relationship. If we use 0.004 then the chance that this guy
actually is related way back is about 16.5%!!! In other words quite
possible. What do you all think?

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