October 22, 2010

mtDNA H1 in North Africa

The 95% CI for North African H1 is 4.4-11.5ky, thus the notion that this reflects post-glacial expansions from Iberia is a bit forced. Also, the age of North African H1 is useless to determine when its ancestors arrived; to achieve that, one should have carried out an estimation of the common ancestor of European and North African H1s; if the two split during the Paleolithic, then the common ancestors would have a correspondingly old age.

The age estimation of the North African specific subclades does put a lower limit to the arrival age, but this is 4.3ky (0-9.8ky 95% CI) for the oldest H1v clade.

Thus, I conclude that an old arrival of H1-related lineages to North Africa is likely, but a pre-Neolithic one is neither supported nor refuted by the data.

PLoS ONE 5(10): e13378. doi:10.1371/journal.pone.0013378

Mitochondrial Haplogroup H1 in North Africa: An Early Holocene Arrival from Iberia

Claudio Ottoni et al.

The Tuareg of the Fezzan region (Libya) are characterized by an extremely high frequency (61%) of haplogroup H1, a mitochondrial DNA (mtDNA) haplogroup that is common in all Western European populations. To define how and when H1 spread from Europe to North Africa up to the Central Sahara, in Fezzan, we investigated the complete mitochondrial genomes of eleven Libyan Tuareg belonging to H1. Coalescence time estimates suggest an arrival of the European H1 mtDNAs at about 8,000–9,000 years ago, while phylogenetic analyses reveal three novel H1 branches, termed H1v, H1w and H1x, which appear to be specific for North African populations, but whose frequencies can be extremely different even in relatively close Tuareg villages. Overall, these findings support the scenario of an arrival of haplogroup H1 in North Africa from Iberia at the beginning of the Holocene, as a consequence of the improvement in climate conditions after the Younger Dryas cold snap, followed by in situ formation of local H1 sub-haplogroups. This process of autochthonous differentiation continues in the Libyan Tuareg who, probably due to isolation and recent founder events, are characterized by village-specific maternal mtDNA lineages.

Link

5 comments:

waggg said...

The 12,000 yrs old (more with the recent revision on carbon dating) Taforalt (north-east of Morocco) bones had 19 % of mtDNA H almost for sure and and 43 % of others were either H or U (Kefi et al. 2005).

Logically, they were probably mostly H1.

http://secher.bernard.free.fr/Articles/P3-%20Kefi%20et%20al%20,%20Anthropologie%202005.pdf

(in French)

Dienekes said...

wagg, your reference lists 4 samples as H?

I ran the first of these (16239T) in mitosearch and got H, I, U8a, H4, H, U*, HV*, HV, H1, U5, HV, U5b matches. A fragment of HVRI is not sufficient for haplogroup assignment.

Andrew Oh-Willeke said...

The directionality of H from North to South, as opposed to visa versa, seems non-obvious, particularly given the apparent H DNA type diversity in the Taforalt population per Dienekes analysis in the comment above. The same can be said for the directionality of haplotype V as being South from Iberia to North Africa or the other way around.

Also, coalescence time estimates, of course, to the extent accurate, are a bound on the earliest date that lines could have split, not the latest date. If those branches emerged in some small coastal Iberian village that wasn't expanding much at the time, those haplotypes could have been in place for thousands of years without travelling far before arriving in Morocco (under the article's hypothesis) with founder effects making subtypes from that village common in Morocco, but vanishingly rare in Iberia (and possibly wiped out at some point for any of a multitude of reasons).

waggg said...

@ Dienekes :

"A fragment of HVRI is not sufficient for haplogroup assignment. "

I can't argue with that but the Ibero-maurusian culture of north Africa seem to have come from south-west of Europe before 10,000 BC. What were their haplogroups in your mind? U5 ? maybe U5 + V ?
It's quite possible (likely, I dare say) these haplogroups were among this population but we can't ignore the fact that the diversity of H1 points to south-west Europe, not north Africa. The highest frequency of H1 is among the basques (like U8a that you mentionned as a possibility, BTW) at 27.8 % IIRC (I let aside the Lybian Tuaregs because the diversity favors Europe as the source). It seem to point to the area of the Franco-Cantabrian refugium.

The people from the Taforalt were cro-magnoids of a type named Mechtoids and some of their remains are found up to Mali and Niger. Among the Fulbe of Burkina Faso (below Mali),Cameroon and Chad were found mtDNA hg U5, H ,V and J1b *. To me, these hgs probably came from the same source, these Mechtoids, that (at least partly) came from Europe probably before 12,000 yrs ago.

* http://findarticles.com/p/articles/mi_qa3659/is_200602/ai_n17186281/

Gioiello said...

Waggg writes: “the Ibero-maurusian culture of north Africa seem to have come from south-west of Europe before 10,000 BC…we can't ignore the fact that the diversity of H1 points to south-west Europe, not north Africa…It seem to point to the area of the Franco-Cantabrian refugium…The people from the Taforalt were cro-magnoids of a type named Mechtoids and some of their remains are found up to Mali and Niger. Among the Fulbe of Burkina Faso (below Mali),Cameroon and Chad were found mtDNA hg U5, H ,V and J1b *. To me, these hgs probably came from the same source, these Mechtoids, that (at least partly) came from Europe probably before 12,000 yrs ago”.

Did these women arrive to North Africa alone? Perhaps as a “white slave trade”? No, of course. They were accompanied by their men: R1b1/V88+. Others had gone to Italy and from them, not the R1b1/V88+ who generated the Sardinian R-M18, but from the R1b1/V88- of the Alpine region arose all the R-subclades of Europe. When the Cruciani’s paper on R1b1 in North Africa was published, I didn’t believe to an origin of it from Middle East, but said either from Italy or from Spain. R1b1 in Africa overlaps the mitochondrial H1 (and also in Middle East).