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Archiver > GENEALOGY-DNA > 2008-09 > 1220797042


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] Age of R1b
Date: Sun, 7 Sep 2008 08:17:22 -0600
References: <47325.24414.qm@web86606.mail.ird.yahoo.com>


----- Original Message -----
From: "Alan R" <>

One thing I will note though is the suggestion of a burst of branching of
R1b lineages suggests some sort of demographic effect.

[[[[ You took the words out of my unwritten message. Ancient demographics
is really the main thing from archaeological investigation that is
significant to y-trees in my view. Demographics controls the y-line
extinction rates through time and hence the fullness or sparseness of the
ydna trees (density of tree nodes). I actually think the promotion of a few
founding MRCAs to be the ancestors of all us males today happens more from a
very bleak period of negligible or negative population growth during which
extinction of line chances can reach greater than 99 percent. And those 1
percent or less of surviving lines have a huge variation in their frequency
in the surviving population that comes out of these bottlenecks. The
subsequent eras of larger population growth and bursting of lines then flesh
out the few surviving lines. But this is all said from just the earliest of
investigations, and "line extinctions" seems to me the next subject which
should be explored in much more depth.

So I'd ask the question: does archaeology give any hints of some very bleak
demographic periods around the times we are talking about? The other thing
I should mention is that this is talked about too much in the context of a
single haplogroup. As dominant as y haplogroup R1b... is in much of Europe,
there were other haplogroups there as well, and the demographics is going to
do the same thing to all the haplogroups present, so inter-haplogroup
correlations of bottlenecks and bursts should be looked for. Ken ]]]]


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