Mitochondrial DNA Heterogeneity in Tunisian Berbers

Abstract

SummaryBerbers live in groups scattered across North Africa whose origins and genetic relationships with their neighbours are not well established. The first hypervariable segment of the mitochondrial DNA (mtDNA) control region was sequenced in a total of 155 individuals from three Tunisian Berber groups and compared to other North Africans. The mtDNA lineages found belong to a common set of mtDNA haplogroups already described in North Africa. Besides the autochthonous North African U6 haplogroup, a group of L3 lineages characterized by the transition at position 16041 seems to be restricted to North Africans, suggesting that an expansion of this group of lineages took place around 10500 years ago in North Africa, and spread to neighbouring populations. Principal components and the coordinate analyses show that some Berber groups (the Tuareg, the Mozabite, and the Chenini-Douiret) are outliers within the North African genetic landscape. This outlier position is consistent with an isolation process followed by genetic drift in haplotype frequencies, and with the high heterogeneity displayed by Berbers compared to Arab samples as shown in the AMOVA. Despite this Berber heterogeneity, no significant differences were found between Berber and Arab samples, suggesting that the Arabization was mainly a cultural process rather than a demographic replacement.

Mitochondrial DNA geneflow indicates preferred usage of the Levant Corridor over the Horn of Africa passageway

“…The presence of Moroccan Berber H individuals may stem from an initial westward migration of the Egyptian Berbers along the North African coast. This hypothesis is consistent with polymorphic H levels in three Tunisian Berber groups (a mean of 21.4 for the Matama, Sened, and Chenini-Douiret Berbers) (Fadhlaoui-Zid et al 2004), which are positioned geographically between Egypt and Morocco.…”

“…There is also uncertainty regarding the route into Egypt, since no J1b lineages are detected in the Jordanians, the Druze of northern Israel (Macaulay et al 1999) or in the Ethiopians ). The very low frequency of J1b among the Matmata Berbers (0.02) and Tunisian Arabs (0.02) (Fadhlaoui-Zid et al 2004) and its apparent absence in various northwest African groups including two populations geographically close to the Strait of Gibraltar (Moroccan Berbers and non-Berber Moroccans in Rando et al 1998) adds complexity to this issue. It is possible that random genetic drift has erased J1b from many populations along its trail(s) (either through the Levant, from Ethiopia to Egypt and/or from North West Africa to Tunisia) after its introduction into Tunisia and Egypt.…”

Mitochondrial DNA Variation in Mauritania and Mali and their Genetic Relationship to Other Western Africa Populations

“…In fact, when linguistically differentiated Berber and Arab populations from Morocco are compared by their L3A frequencies (6% vs 12%; data from Thomas et al 2002; and our unpublished results), significant differences are found between them (P = 0.007), the Berber frequency being similar to that of the Maure. This L3A difference between Berber and Arab speaking groups is extendable to Argelia (7% vs 15%; P < 0.000; data from Côrte-Real et al 1996;Rosa et al 2004 and our unpublished results) and to Tunisia (10% vs 23%; P = 0.028; data from Plaza et al 2003;Fadhlaoui-Zid et al 2004). The latter significance level would be increased if only the most genetically isolated Tunisian Berbers from Chenini-Douiret were compared.…”

The Genetic Impact of the Lake Chad Basin Population in North Africa as Documented by Mitochondrial Diversity and Internal Variation of the L3e5 Haplogroup

“…It was initially described (but unnamed) in Tunisian Berbers (Fadhlaoui-Zid et al, 2004), and later also detected in the LCB where its root type (16041-16223), along with several derived types having few matches elsewhere, appears to be very frequent (Černý et al, 2007). It was further suggested that the evolution of L3e5 took place in the LCB region and that its most recent common ancestor lived there ∼11.5 ka (Černý et al, 2007).…”