Joined: 02 May 2006 {Posts: 363 } Location: Île-de-France
Posted: Fri 05 Sep 2008 15:13 Post subject: Y Haplogroup R1* / M-173
Some more info on R1* outside of northern Cameroon that may show the tracks of a back migration from the middle east to africa.
Quote:
Egypt is the only African population that is known to harbor all three M173 subtypes (R1b-M269, R1*-M173, and R1a1-M17). This unique status is most likely due to Egypt’s strategic location and its long history of interaction with Eurasia. Oman, like Egypt, also exhibits all three M173 haplogroups. The relatively high frequency of R1a1-M17 (9%) may result from the post-LGM expansion associated with this mutation. The expansion estimates of this haplogroup (11.4–3.4 ky; see table 3) support this hypothesis. The above data strongly suggest that the Levantine corridor was, by far, more important than the Horn of Africa passage in the original African dispersal of undifferentiated M173 chromosomes as well as the more recent introduction into Africa of its derivatives, since the M173 mutation is nearly absent in East, Central, and South African collections, except for a 1% frequency in both the Ethiopian (Underhill et al. 2000) and the Hutu assemblages.
A high-resolution, Y-chromosome analysis using 46 binary markers has been carried out in two Jordan populations, one from the metropolitan area of Amman and the other from the Dead Sea, an area geographically isolated. Comparisons with neighboring populations showed that whereas the sample from Amman did not significantly differ from their Levantine neighbors, the Dead Sea sample clearly behaved as a genetic outlier in the region. Its high R1*-M173 frequency (40%) has until now only been found in northern Cameroonian samples. This contrasts with the comparatively low presence of J representatives (9%), which is the modal clade in Middle Eastern populations, including Amman. The Dead Sea sample also showed a high presence of E3b3a-M34 lineages (31%), which is only comparable to that found in Ethiopians. Although ancient and recent ties with sub-Saharan and eastern Africans cannot be discarded, it seems that isolation, strong drift, and/or founder effects are responsible for the anomalous Y-chromosome pool of this population. These results demonstrate that, at a fine scale, the smooth, continental clines detected for several Y-chromosome markers are often disrupted by genetically divergent populations.
Posted: Fri 05 Sep 2008 15:48 Post subject: Re: Y Haplogroup R1* / M-173
That is just fascinating.
I was already aware of the low level (one or two percent) of R1* in Egypt. That barely noticeable trace is why Oppenheimer's charts show the back-migration of 45 kya as going from Asia Minor, through Egypt, then southwest into the Sahara (which was fertile and green back then), and finally countinuing southwestwards to wind up in Cameroon.
But I am uttery stunned by the 40 percent rate found in that Dead Sea population. As far as I am concerned, that is the smoking gun for the back-migration described above. (Assuming, of course, that some Cameroonian army of horny soldiers did not invade the Dead Sea region in ancient times.)
Joined: 07 Oct 2007 {Posts: 203 } Location: United States
Posted: Fri 05 Sep 2008 18:22 Post subject:
I wonder if R1 is found primarily in certain ethnic groups. I understand that in Cameroon, there is a difference in language affinities between southerners and northerners. The southern half of Cameroon are primarily bantu speakers, and the northern half are typically either niger-congo A or Afro Asiatic speakers. There are also some Fulani groups and Kanuri (nilo-saharan groups) toward the middle and northern sections as well. Though I recall fwsweet saying that R1 is found in populations that are as "negroid" looking as you can get, I've heard people calling those groups somewhat less "negroid" looking, usually because of more narrow noses.
Also, I'm wondering if there is some kind of correlation between R1 and T (which is found in fulani groups), both of which indicate somekind of back migration.
I wonder if R1 is found primarily in certain ethnic groups. ... I'm wondering if there is some kind of correlation between R1 and T (which is found in fulani groups), both of which indicate somekind of back migration.
Good questions! Cavalli-Sforza has shown that DNA usually aligns quite well with language and vice-versa. I would love to know the answers.
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