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Archiver > GENEALOGY-DNA > 2010-03 > 1269012701


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] Equivalent Mutations ,relationship between clades and phylogentic tree of Y Chromosome
Date: Fri, 19 Mar 2010 09:31:41 -0600
References: <800388.48060.qm@web26201.mail.ukl.yahoo.com>


----- Original Message -----
From: "Kamel GAZZAH" <>

> Hello,
> Equivalent Mutations ,relationship between clades and phylogentic tree of
> Y Chromosome
>
> By reference to Ytree.ftdna draft version maintained by Thomas,
> equivalent mutations are mutations which are dispalyed in the same line
> (example M410,L152,L212)
> This means that all people who have one of these mutations have also the
> other ones
> but I wonder if is that 100% sure ?


Phylogenetically equivalent snps ONLY means that SO FAR the tested dna has
found the snps equivalently located in the tree. That could be for just two
donors in the worst case, or very many donors in cases where the so-called
equivalent snps have all been tested many times.

You are right; it is sometimes difficult to get donors to pay for tests of
presently phylogenetically equivalent snps. The odds are against them
usually to find some novelty for their increased investment.

It certainly is not for sure that phylogenetically equivalent snps remain so
upon further testing.

But some snps will remain absolutely phylogenetically equivalent for the
tree leading to today's population. This is because the tree for this
situation consists of branch line segments connected together at nodes. The
branch line segments are of various lengths in generations, and more than
one snp can have happened somewhere on the same branch segment. There is no
way with living dna donors to see what is going on within each branch
segment --- we see just the whole packages. So two snps on the same branch
segment will forever remain phylogenetically equivalent.

Digging up old bones and measuring the snps changes this story a little. We
are now looking at a thicker set of branches, as the branch lines which went
extinct before today can come into play. Old bones may have some snps seen
which will never be seen in live donor dna from the same region of the tree.



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