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From: Bonnie Schrack <>
Subject: Re: [DNA] Haplogroup J2 frequency
Date: Mon, 07 Aug 2006 18:10:55 -0400


Jackson asked,

> Does anyone know which country has the highest proportion of Y-DNA
> haplogroup J2 in the world?

It's hard to say for sure, but in Al-Zahery (2003), Y-chromosome and
mtDNA polymorphisms in Iraq, a crossroad of the early human dispersal
and of post-Neolithic migrations, they say,

> As for the Y chromosome, the distinguishing feature
> of the Iraqis is the extremely high frequency (58.3%) of
> the haplogroup J-12f2. This, together with the values
> observed in Syria and in the Zagros Mountains of Iran, is
> the highest incidence reported so far (Hammer et al.,
> 2000; Mitchell et al., 1993; Nebel et al., 2001; Quintana-
> Murci et al., 2001; Ritte et al., 1993; Santachiara-Benerecetti
> et al., 1993; Semino et al., 1996, 2000a; Wells et al., 2001)

Interestingly, Al-Zahery has some ideas about J1 and J2 that are worth
considering. Note that J(xM172) represents J1 in his text. He was
correct to hypothesize that

> all (or most) of the J(xM172) Y chromosomes might represent a
> monophyletic cluster
> defined by yet unidentified mutations

The mutation which had not yet been identified at that time was M267,
which defines J1.

> When J-M172 and J(xM172) are compared, a higher variation
> both for the 49a,f system and for eight microsatellites
> (Santachiara-Benerecetti et al., unpublished data) is observed
> in J-M172 (h = 0:947 vs. 0.844), and the internal
> microsatellite variance of J-M172 is more than twice that
> of J(xM172). Thus, whatever the real age of these two
> lineages may be (age evaluations for the Y chromosome
> are always very uncertain, Brinkmann et al., 1998; Forster
> et al., 2000), J-M172 appears to be older than
> J(xM172). This consideration, which is in agreement
> with the data of Nebel et al. (2001) relative to other
> Middle Eastern populations, is apparently in contrast
> with the Y-chromosome phylogeny (Fig. 3) that derives
> J(xM172) directly from the node 12f2-8Kb, whereas JM172
> is derived through a further mutation (M172).
> These data suggest that all (or most) of the J(xM172) Y
> chromosomes might represent a monophyletic cluster
> defined by yet unidentified mutations. The lower variability
> of J(xM172) with respect to J-M172, together with
> the different distribution of these two lineages in the
> Middle East and in surrounding areas affected byMiddle
> Eastern migrations, may suggest that they evolved in two
> separate human groups with a previous common ancestry
> and underwent expansions at different times. In
> particular, it seems reasonable to assume that the haplogroup
> J-M172 expanded first, possibly from the
> Northwestern part of the Fertile Crescent (Asia Minor),
> where agriculture actually started and triggered the development
> and growth of other Middle Eastern populations.
> On the other hand, J(xM172) seems to have had
> its center in the Eastern part of the Fertile Crescent (Iraq
> and Iran), and to have undergone a later expansion
> mainly affecting modern Arab populations (Cruciani
> et al., 2002; Nebel et al., 2001; Semino et al., 2002).

The latter part of this is a very useful set of hypotheses about J2 and
J1 that we would do well to keep in mind.

The data that I have accumulated so far over the last year or two agrees
with the observation here that the microsatellite variance of J2 is much
higher than that of J1. Others have noticed this, and the theory that
J2 expanded first and thus has had more time to accumulate haplotype
variation seems the best explanation.

Bonnie



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