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Archiver > DNA-R1B1C7 > 2012-03 > 1332918939


From: "Sandy Paterson" <>
Subject: Re: [R-M222] Geographical distribution of M222+
Date: Wed, 28 Mar 2012 08:15:39 +0100
References: <mailman.33.1332831605.6995.dna-r1b1c7@rootsweb.com> <4F71B0A6.6070005@earthlink.net><89EF7258-4726-4158-A2DF-C21E442D1E70@me.com>
In-Reply-To: <89EF7258-4726-4158-A2DF-C21E442D1E70@me.com>


Malcolm

I don't believe what Mike did in dividing the sum of observed variances of
M222+ by those of P312 is an abuse at all. Of the 111 markers in the largest
FTDNA test, only about 35 of the mutation rates are (reasonably)
well-researched the remaining 76 have to be estimated in order to do
estimated TMRCA calculations. Of the 67-marker panel, about 26 are fairly
well-researched, with very little known about the remaining 41.

I have chosen for the most part to quote sum of variances rather than
ETMRCA, but Mike chose to quote ratios to P312. So when he quotes a figure
of 0.63 for M222+, that means by his estimate, M222+ is about 63% as old as
P312. I can't see anything wrong with that at all, although I don't believe
it is accurate to use fewer than around 50 markers in the summation. In any
event, ETMRCAs are not normally distributed, they are skewed, with a long
tail at the high values and a shorter tail at the lower values.

Sandy




-----Original Message-----
From:
[mailto:] On Behalf Of Malcolm McClure
Sent: 27 March 2012 14:56
To: ;
Subject: Re: [R-M222] Geographical distribution of M222+

Susan

I welcome your clear statement about the aims and objectives of M222
correspondence.
It was beginning to get diverted by speculations about the dim and distant
past rather than being confined to evidence concerning the relevant past two
millennia. Until we can establish a clearer identity for our tribal
antecedents, their strifes and allegiances over the generations, their
migrations and bottlenecks, we are unlikely to establish individual family
and surname antecedents with confidence.
The recent correspondence about Variance ratios seems to me to be a misuse
of statistical tools that were devised to reflect the shape of Normal
Distributions based on a single measurable variable. Lumping variables makes
for nonsense statistics.— Just my 2¢ worth.

Malcolm.



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