GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2005-11 > 1133280665
Subject: Re: [DNA] YSNP testing, hobby scientist forces, convergence, and back mutatio...
Date: Tue, 29 Nov 2005 11:11:05 EST
In a message dated 11/28/05 9:17:17 PM Pacific Standard Time,
> It would seem to me that 1st
> cousins should always be closer on marker values than more distant cousins.
First cousins will be closer than distant cousins ON THE AVERAGE, but
mutations are random events. Even two brothers can differ: one brother can match his
father, who matches his fifth great-grandfather, but the other brother can
have a mutation (or rarely, even two -- Dupuy found one case in his study of
1,766 father/son pairs using 10 loci).
> I also have to think about your "time ordering" in a branch not to "time
> scale". Had assumed that the YCC chart was drawn with a pre-set time scale
> from left to right and from top to bottom... Hap A was the oldest at the top
> and Hap R was the newest haplogroup at right bottom; and, the YCC chart was
> proportionately right. Perhaps as your other email indicated....we should
> wait for better aging on SNP before a new proportionally correct chart can
> be drawn.
I discussed this in a different context recently.
The vertical lines certainly give a tidy visual impression of events
occurring at the same time. But the reality is much messier, and dates are not well
established. For instance, look at the "pivot point" that leads to C and the
superhaplogroup F. If you imagine that the vertical lines can bend left and right
at that point to show a real time scale on the horizontal axis, you could
equally well move C to the left or to the right of F.
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