Thursday, August 23, 2012
Did Haplogroup R1 Originate in Africa ?
In a new article on the R1 clade, The genetic landscape of Equatorial Guinea and the origin and migration routes of the Y chromosome haplogroup R-V88 Gonzalez et al, argue that R1 probably spread across Europe from Iberia to the east given the distribution of R1 in Africa.
In my paper POSSIBLE AFRICAN ORIGIN OF Y-CHROMOSOME R1-M173:here ;
I argue that the P clade originated in Africa because 1) the age of R-V88 and 2) the widespread nature of R1 in Africa. Researchers have found that the TMRCA of V88 was
9200-5600 kya (Cruciani et al, 2010). Eurasians carry the M269 (R1b1b2) mutation. The subclades of R1b1b2 include Rh1b1b2g (U106) (TMRCA 8.3kya) and R1b1b2h (U152) (TMRCA 7.4kya). The most recent common ancestor for R1b1b2 in Europe is probably 8kya (Balaresque et al, 2010). Y-Chromosome R1b1b2 has high frequencies in England, France, Italy and Germany (Balaresque et al, 2010). Clearly, R-V88 is older than R-M269 .
The new article by Gonzalez et al adds further support to my theory. The researchers propose that the R haplogroup did not spread from East Africa.
European Journal of Human Genetics advance online publication 15 August 2012; doi: 10.1038/ejhg.2012.167
The genetic landscape of Equatorial Guinea and the origin and migration routes of the Y chromosome haplogroup R-V88
Advance online publication 15 August 2012
Human Y chromosomes belonging to the haplogroup R1b1-P25, although very common in Europe, are usually rare in Africa. However, recently published studies have reported high frequencies of this haplogroup in the central-western region of the African continent and proposed that this represents a ‘back-to-Africa’ migration during prehistoric times. To obtain a deeper insight into the history of these lineages, we characterised the paternal genetic background of a population in Equatorial Guinea, a Central-West African country located near the region in which the highest frequencies of the R1b1 haplogroup in Africa have been found to date. In our sample, the large majority (78.6%) of the sequences belong to subclades in haplogroup E, which are the most frequent in Bantu groups. However, the frequency of the R1b1 haplogroup in our sample (17.0%) was higher than that previously observed for the majority of the African continent. Of these R1b1 samples, nine are defined by the V88 marker, which was recently discovered in Africa. As high microsatellite variance was found inside this haplogroup in Central-West Africa and a decrease in this variance was observed towards Northeast Africa, our findings do not support the previously hypothesised movement of Chadic-speaking people from the North across the Sahara as the explanation for these R1b1 lineages in Central-West Africa. The present findings are also compatible with an origin of the V88-derived allele in the Central-West Africa, and its presence in North Africa may be better explained as the result of a migration from the south during the mid-Holocene.
Central-West Africa; Equatorial Guinea; human male lineages; Y chromosome; haplogroup R-V88; back to Africa hypothesis
The Gonzalez et al article is further proof of the African origin for y-chromosome R1’ The researchers found that 10 out of 19 subjects in the study carried R1b1-P25 or M269. This is highly significant because it indicates that 53% of the R1 carriers were M269. the finding is further proof of the widespread nature of this so-called Eurasian genes in Africa among populations that have not mated with Europeans.
Gonzalez et al proposes a West to East spread for P-25, with a possible entry of this clade via Gibraltar.