May 20, 2009

mtDNA of Libyan Tuaregs

The sample consisted of haplogroups H1, V, M1, and an assortment of African L subclades.

From the paper:
Of note is that the other Tuareg sample described in the literature (Watson et al., 1996) (Western Tuaregs) did not show a close genetic relationship with the Libyan Tuaregs, implying a genetic heterogeneity of the Tuaregs. This difference appears to be primarily caused by the low frequency (8%) of the European component in the Western Tuaregs, characteristic of northern African populations. After the removal of the H and V haplotypes, the Libyan Tuaregs showed a strong affiliation with the Eastern populations, while theWestern Tuaregs associated more with the Central and Western African populations (Fig. 2).
In other words, the Libyan Tuaregs are primarily "European"+"Eastern African" (or Saharan) in affiliation, while the Western Tuaregs from Nigeria, Niger, and Mali have a predominantly West African maternal heritage.

Annals of Human Genetics doi:10.1111/j.1469-1809.2009.00526.x

First Genetic Insight into Libyan Tuaregs: A Maternal Perspective

Claudio Ottoni et al.

Abstract

The Tuaregs are a semi-nomadic pastoralist people of northwest Africa. Their origins are still a matter of debate due to the scarcity of genetic and historical data. Here we report the first data on the mitochondrial DNA (mtDNA) genetic characterization of a Tuareg sample from Fezzan (Libyan Sahara). A total of 129 individuals from two villages in the Acacus region were genetically analysed. Both the hypervariable regions and the coding region of mtDNA were investigated. Phylogeographic investigation was carried out in order to reconstruct human migratory shifts in central Sahara, and to shed light on the origin of the Libyan Tuaregs. Our results clearly show low genetic diversity in the sample, possibly due to genetic drift and founder effect associated with the separation of Libyan Tuaregs from an ancestral population. Furthermore, the maternal genetic pool of the Libyan Tuaregs is characterized by a major "European" component shared with the Berbers that could be traced to the Iberian Peninsula, as well as a minor 'south Saharan' contribution possibly linked to both Eastern African and Near Eastern populations.

Link

4 comments:

Maju said...

Link is broken. From Mathilda's I got this link (PDF).

It's a long paper, rather an e-book (a doctoral thesis in fact), but very worth reading, as it does not only analyzes mtDNA but also makes a comprehensive review at the beginning of African, and even some European, prehistoric and gentic info.

It is very interesting that all reported Tuareg samples are 2/3 HV (mostly H1, and mostly with the CRS haplotype motiff - not the same as "CRS haplogroup", which would be H2a). This links with North African high presence of SW European-derived HV (H1, H3 and V basically) but is much more marked possibly because of founder effect. Instead typical North African haplogroup U6 is absent, while the fraction of L(xM,N) is larger than among average North Africans (though in many cases the Tuareg L haplotypes are close to a possibly East African root).

Gioiello said...

Many thanks for the link.

Ponto said...

Interesting reading these PhD theses. Shows the work you have to do to get a doctorate.

H1, H3 and V mtDNA haplogroups are most frequent in Iberia, taking into account the lack of diversity in the mtDNA V found in the Saami. The three mtDNA haplogroups are thought to be native to Iberia and spread from there after the last glacial maximum. There have been studies on those haplogroups done previously that show those conclusions. V haplogroup, my mtDNA haplogroup, has not been found in the remains from ancient cemeteries in the Basque zone of Iberia. This lack gives the native to Iberia claim less grounding. It could well have originated in NW Africa. Its origins are not resolved.

While I enjoyed the thesis, I think these type of studies are flawed with assumptions of ultimate origins. H1, H3 and V mtDNA haplogroups might be European in origin, ultimately the source of HV is in the Middle East as is most subclades of mtDNA H which means it is pointless to attribute origins to haplogroups that originate in mostly or wholly Caucasoid people which is the geographical area from Western Eurasia to North and Northeast Africa. Europe is a mere extension of Asia.

Maju said...

V haplogroup, my mtDNA haplogroup, has not been found in the remains from ancient cemeteries in the Basque zone of Iberia.

This was the main rationale for some to argue that aDNA "disproved" any connection with modern Basques. Yet modern Basques in the areas sampled in that study are very low in mtDNA V (3%). Gipuzkoans are high (11%) but no cemetery was sampled in that province.

MtDNA V anyhow seems more directly linked to other populations anyhow. In some studies Catalans were high in this lineage, while in others they were not.

This lack gives the native to Iberia claim less grounding.

Can you guys stop mixing Basques and Iberians? We are clearly in two different genetic and archaeological provinces (though interconnected within the context of Europe). Basques would be if anything descendants of the peoples of the Franco-Cantabrian area, north of the mountains and in general, notwithstanding some Neolithic flows via the Ebro, we relate most tightly with Gascons (and surely other Occitans too). These peoples do not live in Iberia.

... it is pointless to attribute origins to haplogroups that originate in mostly or wholly Caucasoid people which is the geographical area from Western Eurasia to North and Northeast Africa. Europe is a mere extension of Asia.

But North African H (and V) is mostly a subset of Iberian variability. HV coalesced in West Asia but its descendants H1 and H3 (and surely V) did not. IMO, H itself shows clear signs of European-specific origin and, having that striking starlike structure (that I can only compare with mtDNA M because of the huge number of sublineages stemming directly from the basal node), suggests a very fast expansion within Europe, in Aurignacian and/or Gravettian periods.