Archiver > GENEALOGY-DNA > 2009-12 > 1260200247

From: "Ken Nordtvedt" <>
Subject: Re: [DNA] R-U152 and R-L21 on the European Continent
Date: Mon, 7 Dec 2009 08:37:27 -0700
References: <> <><><006701ca76ef$d0ab50b0$7201f210$@org><003201ca76f3$ee2dcd30$6400a8c0@Ken1><91E2D25B95804417B98E786B9CB9E69B@bobPC><00ac01ca774c$e11bdd40$6400a8c0@Ken1>

I regret repeating the formulation "average mutation rates" without more
explanation. STRs each have intrinsic mutation rates --- an attribute of
the biological machinery and its environment determined by chemistry and
physics. We can observe the STRs over some period of time and showing some
number of mutations, and thereby record an average observed mutation rate as
measurements of the intrinsic rates.

"Average mutation rate" is a mathematical construct for a collection of
STRs. I, personally, don't recommend using such a construct because it
possibly puts false images in mind. But if we have 3 STRs, one with
intrinsic mutation rate 1/1000, one with rate 2/1000, and one with 4/1000,
one can call the average mutation rate of those 3 STRs 7/3000, but there are
really three STRs with three different rates of mutation.

----- Original Message -----
From: "Ken Nordtvedt" <>
To: <>
Sent: Monday, December 07, 2009 7:52 AM
Subject: Re: [DNA] R-U152 and R-L21 on the European Continent

> The nuisance is that some people invent bogus "effective" rates. I don't
> think average mutation rates vary in nature very much due to different
> physical conditions, although there could be some of that. In any case,
> the
> mutation behaviors of the different STRs are to be directly measured.

>> It is a real nuisance that
>> mutations vary
>> rates of mutation vary
>> and average mutation rates vary.
>> Bob

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