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Archiver > GENEALOGY-DNA > 2004-12 > 1104339970


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] 385a,b Upheaval in R1b (WAS: Can 385a,b = 14,15 be 15/14?)
Date: Wed, 29 Dec 2004 10:06:10 -0700
References: <60.4be2e8cf.2f0439aa@aol.com>


What to some is an obstacle to others is a challenge and opportunity. I
think tackling 464 calls for much, much larger databases and someone willing
to write clever search software to sort such a marker out, but double
markers like 385 are another story.

Superposition of two populations within a haplogroup will primarily occur
when 385 in that haplogroup includes a degenerate set of repeat values like
14, 14 in the midst of its population. That makes the neighboring 385
values 13, 14 and 14, 15 prone to be well-populated from 14,14 in both their
true underlying manifestations --- 13,14 or 14,13 in one case; 14,15 or
15,14 in the other.

Statistically speaking --- and that's all that matters in population
studies --- when a haplogroup's 385 pair of modal values are far apart you
may as well treat them as a single population although you won't know which
it is.

For haplogroup I, geography and bi-modality at other markers then offers
the handles to objectively discern that 13, 14, for example, really consists
of two populations, each with its own history and settlement patterns.

Ken


----- Original Message -----
From: <>
To: <>
Sent: Wednesday, December 29, 2004 9:47 AM
Subject: Re: [DNA] 385a,b Upheaval in R1b (WAS: Can 385a,b = 14,15 be
15/14?)


> First let me hasten to see that the problems with multi-copy markers are
not
> of great concern for projects dealing with the genealogical time frame. If
you
> have a cluster of people who match on most markers, you don't really need
to
> worry about whether some of them are really DYS385a/b 11,14 while others
are
> really 14,11.
>
> In fact, I've only encountered one case where the difference might have
been
> significant for a haplogroup assignment, where a person was estimated to
be
> R1a but turned out to be R1b on a SNP test. He was not very close to the
modal
> values for either haplogroup. I wrote this up in some detail last
November:
>
> http://archiver.rootsweb.com/th/read/GENEALOGY-DNA/2003-11/1068521518
>
> That was before Whit came out with his haplogroup predictor. If someone
has
> time to run Don's numbers through the predictor, that could be
interesting.
>
> As far as population geneticists are concerned, I've seen articles where
the
> authors eliminate multi-copy markers from their phylogenetic analyses.
I've
> always recommended omitting DYS464 from Fluxus calculations, too. The
modal
> values for R1b are 15-15-17-17, which makes it particularly problematic to
know
> which marker changed if someone has 14-15-17-717 or 15-15-16-17.
>
> For Ken's work on Haplogroup I, I'm not familiar enough with the ins and
outs
> of all his analysis to comment on whether he should eliminate the
multi-copy
> markers. But I've always been a bit uneasy with making deductions from
modal
> values which are close to each other, even when they are on distinct
markers.
> It gets very fuzzy when results could be identical by descent (IBD) or
> identical by state (IBS).
>
> Ann Turner - GENEALOGY-DNA List Administrator
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>
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