Tuesday, May 1, 2012

News Flash: Developments with Y Haplogroup A

Paul Conroy sends me news of an unfolding story that is taking place in the personal genomics sphere.  The Y Haplogroup A project has found a descendant of Albert Perry, a person of African descent, who has been database matched to people in the vicinity of Buea, of coastal Cameroon.  It is exciting that a match can be found to a specific location in Africa, particularly because most people of African American descent end up with a generalized place of origin for their paternal ancestor.  This A0 result is exceptionally interesting because the STR values indicate that Mr. Perry's y haplogroup represents an early branch on the A0 tree.

Bonnie Schrack, the Group Administrator for the Y Haplogroup A project has this to say: 

"There is a huge amount of interest in questions related to human origins, out-of-Africa migrations, interbreeding with archaic humans, etc., etc., which people feel that the A haplogroup (as it's called, though it actually incorporates several haplogroups) will help to illuminate. For anyone out there who has been out of the loop, this is because of findings by Cruciani last year which showed all haplogroups descending from a branch of A. I have now updated the ISOGG haplogroup A tree to show this."

"The other side of the first main branching of A, the one from which other haplogroups are *not *descended, is being called A0. (The rest of us are descended from A1, which can also be called A1T.) A0 is very rare, so far found in Cameroon and Ghana, and we are only beginning to find out how many branches are within it. Cruciani and previous scientists were only aware of one branch, which they called A1b. Thanks to research we're doing in our Haplogroup A project, with the great contributions of Thomas Krahn, we now have two branches, A0a and A0b, both downstream of 16 A0* SNPs (though A0b is not quite ready to show on the ISOGG tree, as a second set of positive test results for the new SNPs are required for these SNPs to gain a non-private status, so we have to wait a little for these SNPs to be ordered and tested)."

"Perry's results apparently will establish a third branch of A0, which branches off earlier than the current A0a and A0b. Thus the great interest."

Even prior to DNA testing (Veeramah et al), Cameroon was thought to be one of the few forest refuges which survived continuously intact during the arid phases that Africa was exposed to during the Quaternary (J. Maley).  Thus it is possible that Perry's paternal African ancestors had been in place in Cameroon since before the beginning of the African great arid phase which began 70,000 years ago. 

It's an impressive result for personal genomics.   I will be interested to follow this story as it develops.

References:

RootsWeb:  Kit N64496 HAS NO HAPLOGROUP AT ALL (Link)

Tishkoff, SA; et al. (22 May 2009).  "The genetic structure and history of Africans and African Americans", Science, 324(5930):1035-44. Epub 2009 Apr 30. (Link)

Cruciani, Fulvio; et al. (19 May 2011). "Revised Root for the Human Y Chromosomal Phylogenetic Tree:  The Origin of Patrilineal Diversity in Africa." doi:10.1016/j.ajhg.2011.05.002.

Veeramah, Krishna R.; et al.  (2010). "Little genetic differentiation as assessed by uniparental markers in the presence of substantial language variation in peoples of the Cross River region of Nigeria", BMC Evolutionary Biology, 10:92. (Link)

Maley, J; "The climatic and vegetational history of the equatorial of Africa during the upper Quaternary" in The Archaeology of Africa, Food, Metals and Towns, Shaw, Sinclair, Andah and Okpoko (editors), 1993.

2 comments:

  1. According to the original paper A0 (then still described as A1b) was found among Pygmies from Cameroon (8.3%) and the Mozabites of Algeria (1.5%) and not only in Cameroon.

    Also I have a minor qualm with the confusing terminology of Bonnie Schrack as in the quote, because what she describes as "A0*" is actually (from context) A0-root or the A0 ancestral node. A0* is the paraphyletic group of directly attested (usually modern) lineages that do not fit in any other category, so her A0b is actually A0* until proven otherwise.

    Luckily there is no such confusion in the FTDNA page, which is more carefully worded.

    Interesting in any case.

    Otherwise it is interesting to know that the haplogroup has been renamed.

    I am understanding that the Buea sample is non-Pygmy group but I'd like to have some more information about their exact ethnic adscription if known. Cameroon is such an ethnographic mosaic!

    ReplyDelete
  2. Maju,

    There are other proposed Quaternary arid phase refuges Africa. They have been extensively research by J. Maley. His chapter in the Archaeology of Africa book is really a summary of his work. It wasn't my intension to imply that this sample indicates a Cameroon only origin for A0. However, it does support the notion that Cameroon was one of a small number of refuges for modern humans during the great arid phase in Africa during the last 70,000 years.

    I've added the Veeramah et al reference which assessed Cameroon (Northwest Province) as well as Nigerian and Ghanaian samples.

    I'm sure that more will be published on the genetic identity of the people of Cameroon. In terms of ethnic group association of this sample, I believe the comments of Professor Rasmus Nielson provide food for thought:

    Do the genes belong to the tribal council?
    http://cteg.berkeley.edu/~nielsen/2011/do-the-genes-belong-to-the-tribal-council/

    ReplyDelete

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