GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2010-02 > 1266434047


From: "Anatole Klyosov" <>
Subject: Re: [DNA] "counting mutations" versus "GD from the modal"
Date: Wed, 17 Feb 2010 14:14:08 -0500
References: <mailman.5375.1266431628.2099.genealogy-dna@rootsweb.com>


From: Sasson Margaliot <>


Dear Sasson,

There is good concept called a "paradigm". It assumes that people who
discuss things are on the same wavelength regarding basic principles.
Otherwise there is no point to discuss. It is astonishing that when someone
talks on a common ancestor of a certain dataset, another someone jumps high
and asked "do you mean Adam"? Is it a (temporary) insanity, or a burning
desire to bite, even without teeth?

I think it goes without saying that by "a common ancestor" of a group of
haplotypes we mean a nearest common ancestor. It happens that some (many)
datasets contain two a more distinct lineages. In J1 "CMH" one subpopulation
has a common ancestor (a nearest common ancestor, for those who still did
not get it) of about 1,000 ybp, another subpopulation's common ancestor is
of 4200 years bp. As a result of that mix, the dataset has plenty of base
haplotypes, however, they are NOT base haplotypes from the whole dataset.
There is another base haplotype of the older subpopulation. That mix does
not follow the first order kinetics, and the data cannot be calculated
without separating of the two sub-populations.

By the way, I would call that J1 1000-year old common ancestor as "J1-CMH",
and year, he is no older than that, and the another J1-4200-years old common
ancestor I would call "J1-AbrahamMH". It is the same in the Arabs, the same
base haplotype and the same 4200-ybp common ancestor. It is of a great (for
me) interest that in J2 haplogroup (J2a) a common ancestor of the Jews and
the Arabs lived.... well... the same 4200 ybp.

There were two Abrahams, believe it or not. One J1, another J2. Are you
still able to be surprised with something? By the way, J2 Cohanim have a
more kosher TMRCA, of 3300 ybp.

Did you suggest, Sasson, a while ago, that J2 Cohamin have more kosher
TMRCA? You were right,.

Regards,

Anatole Klyosov

*********************************

>Sasson:
>I think I can help with the definition of "Common Ancestor". In everyday
English, a "common ancestor" for a set X of individuals, is someone who
simply is an ancestor common to all members of X.

Unlike everyday English, in this discussion we restrict our attention to
strict patrilinear ancestors only, so Anatole no the only one here who uses
common terms in a special sense, we all do. In a simple sense, common
ancestors for X are the MRCA of X and all his "fathers" all the way up to
Adam.

Anatole is consistently using the term "Common Ancestors" of X in the sense
of exactly "MRCAs of significant, prominent sub-clusters" of X. The precise
protocol of how we should decide which clusters are "significant, prominent"
ones was not presented here, but in practice all the cases are rather clear.

Let me give a specific example: the collection of J1 Cohens. It was fed to
Generations2, returning 2300 years. Then it was examined according to
Anatole's method, and it was discovered that the set has a prominent
sub-set corresponding to a branch which is 1400 years old. The MRCA of
the rest is more like 4000. All numbers are approximate, but the situation
is precisely clear.

You see, all the extra-precision of Generation2 algorithm didn't help at
all.

This is the famous Cohen problem, which is in the center of attention for
more than ten years, the last 15 years, of hobbyists and academics alike -
but it was ONLY possible to receive the right results by subjecting the data
to Anatole's method.

Bottom line: a "Common Ancestor" is the founder of such a sub-cluster that
just has to be calculated separately. By the way, once these "significant,
prominent" sub-clusters are already found, the verification of their
"regularity" is relatively straightforward.

I would rather call Anatole's "Common ancestors" "Founding Fathers". It's
not unusual for one of the "Founding Fathers" of X to turn out to be an
ancestor of all others.

Sasson



This thread: