Insights into the Middle Eastern paternal genetic pool in Tunisia: high prevalence of T-M70 haplogroup in an Arab population.

To obtain refreshed insights into the paternal lineages of Tunisian populations, Y-chromosome diversity was assessed in two populations belonging to an Arab genealogical lineage, Kairouan and Wesletia, as well as in four Tunisian Andalusian populations, Testour, Slouguia, Qalaat-El-Andalous and El Alia. The Arabs from Kairouan revealed 73.47% of E-M81 and close affinities with Berber groups, indicating they are likely arabized Berbers, clearly differentiated from the Arabs from Wesletia, who harbored the highest frequency (71.8%) of the Middle Eastern component ever observed in North Africa. In the Tunisian Andalusians, the North African component largely prevailed, followed by the Middle Eastern contribution. Global comparative analysis highlighted the heterogeneity of Tunisian populations, among which, as a whole, dominated a set of lineages ascribed to be of autochthonous Berber origin (71.67%), beside a component of essentially Middle Eastern extraction (18.35%), and signatures of Sub-Saharan (5.2%), European (3.45%) and Asiatic (1.33%) contributions. The remarkable frequency of T-M70 in Wesletia (17.4%) prompted to refine its phylogeographic analysis, allowing to confirm its Middle Eastern origin, though signs of local evolution in Northern Africa were also detected. Evidence was clear on the ancient introduction of T lineages into the region, probably since Neolithic times associated to spread of agriculture.

A Distinctive Pattern of Diversity for the TAS2R38 Gene in North Africa.

The TAS2R38 gene is involved in bitter taste perception. This study documents the distinctive diversity patterns in northern Africa of functional single-nucleotide polymorphisms (SNPs) rs713598 and rs1726866 at the TAS2R38 locus and places those patterns in the context of global TAS2R38 diversity. Data previously genotyped with TaqMan assay were analyzed for rs713598 and rs1726866 for 375 unrelated subjects (305 Tunisians from seven locations: Mahdia, Sousse, Kesra, Nebeur, Kairouan, Smar, and Kerkennah; plus 70 Libyans). Data were analyzed to present haplotypes and genotypes before comparison with data from worldwide populations. This study provides information about TAS2R38 diversity in a part of the world that is relatively understudied. Considering the two SNPs rs713598 and rs1726866, the CA nucleotide haplotype leading to the PV amino acid haplotype is extremely rare almost everywhere, but it is relatively frequent (between 6% and 15%) in northern Africa, where it coexists with the globally common amino acid haplotypes PA, AA, and AV. Given its higher frequency in North Africa, the authors propose the CA nucleotide haplotype as a biogeographic marker for forensic purposes.

Evolution of inbreeding coefficients and effective size in the population of Saguenay Lac-St.-Jean (Quebec).

We computed mean inbreeding coefficients (FIT, FIS, and FST) based on approximately 2,700 ascending pedigrees of contemporary people from Saguenay Lac-St-Jean (Québec, Canada). This allowed us to appreciate the accumulated inbreeding and to follow the evolution of these coefficients since the founding of Québec. One of the results was the expected increase in FST. Relying on this parameter, we computed the effective size (Ne) of the contemporary population, obtaining a value around 1,000, in agreement with previous estimations. We noticed a decrease of Ne through history despite the population's growing size.