GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2009-12 > 1260516645


From: "Tim Janzen" <>
Subject: Re: [DNA] R-U152 and R-L21 on the European Continent
Date: Thu, 10 Dec 2009 23:30:45 -0800
In-Reply-To: <00b501ca79b8$d3898970$6400a8c0@Ken1>


Dear Ken,
I think that Al's point is that you need to be careful which markers
you include in the analysis depending on what you are trying to study.
Including a lot of fast mutating markers in the group of markers used for
interclade TMRCA estimates is fine if you are simply trying to determine the
ages of nodes for relatively young subclades (3000 years old or so and
younger). However, as I pointed out in various messages this summer,
including a lot of fast mutating markers in the group of markers used for
interclade TMRCA estimates for subclades or haplogroups 10,000 or more years
old will invariably skew the ages to be lower than they are likely to be in
actuality. See
http://archiver.rootsweb.ancestry.com/th/read/GENEALOGY-DNA/2009-07/12467369
45,
http://archiver.rootsweb.ancestry.com/th/read/GENEALOGY-DNA/2009-07/12489369
44 and other messages in July and August for background. However, we also
have a problem in that John Chandler's estimated mutation rates for the
slowest 10 or so mutating markers in the 67-marker FTDNA panel probably are
a lower than they are in reality. This has the effect of skewing interclade
TMRCA estimates to be older than they are likely to be in reality if the
slowest mutation markers are used in the estimates.
I think we need to do more analysis on haplotypes from groups where
there is a documented geographical separation of a haplogroup and where the
timing of the separation is relatively well documented based on
archeological data. In particular, I think we need to look at splits that
occurred over 10,000 years ago as our best reference points. Two of the
best documented geographic separations are the immigration of Native
Americans into N. America (ca 15,000 years ago or so) and the immigration of
Australian Aborigines into Australia (ca 40,000 years ago). Haplogroups Q
and C migrated into N. America and haplogroup C migrated into Australia. I
have done work on the Haplogroups Q for Native Americans (see
http://archiver.rootsweb.ancestry.com/th/read/GENEALOGY-DNA/2009-06/12462577
85,
http://archiver.rootsweb.ancestry.com/th/read/GENEALOGY-DNA/2009-07/12465582
30 and the first message I mentioned above). If we had a good selection of
67-marker Haplogroup C haplotypes from Australian Aborigines and also a
group from elsewhere in southern Asia, we could do interclade TMRCA
estimates to see how close they are to 40,000 years. The number of
haplotypes in the haplogroup C project at
http://www.familytreedna.com/public/Chaplogroup is relatively few. Are
there Haplogroup C haplotypes from Australian Aborigines available anywhere
for analysis?
Sincerely,
Tim Janzen

-----Original Message-----
From:
[mailto:] On Behalf Of Ken Nordtvedt
Sent: Thursday, December 10, 2009 8:50 AM
To:
Subject: Re: [DNA] R-U152 and R-L21 on the European Continent

I don't think there is any "right" mix of markers. There may be more
well-behaved (easier to model) markers, however.

If one can represent the behavior of markers mathematically, that's all that

counts for including them into variance age estimates. We do want the
maximum total mutational power (rate) in order to have the tightest possible

statistical confidence intervals to the estimates. So one throws away
markers only for solid reasons.

Ken


----- Original Message -----
From: "Al Aburto" <>

> I think when we get the _right_ mix of markers to use that correspond to
> the actual mix of fast & slow markers in the Y-chromosome that we'll be
> happier ...
> Al


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