Genetic structure of Tunisian ethnic groups revealed by paternal lineages

Abstract

Tunisia has experienced a variety of human migrations that have modeled the myriad cultural groups inhabiting the area. Both Arabic and Berber-speaking populations live in Tunisia. Berbers are commonly considered as in situ descendants of peoples who settled roughly in Palaeolithic times, and posterior demographic events such as the arrival of the Neolithic, the Arab migrations, and the expulsion of the "Moors" from Spain, had a strong cultural influence. Nonetheless, the genetic structure and the population relationships of the ethnic groups living in Tunisia have been poorly assessed. In order to gain insight into the paternal genetic landscape and population structure, more than 40 Y-chromosome single nucleotide polymorphisms and 17 short tandem repeats were analyzed in five Tunisian ethnic groups (three Berber-speaking isolates, one Andalusian, and one Cosmopolitan Arab). The most common lineage was the North African haplogroup E-M81 (71%), being fixed in two Berber samples (Chenini-Douiret and Jradou), suggesting isolation and genetic drift. Differential levels of paternal gene flow from the Near East were detected in the Tunisian samples (J-M267 lineage over 30%); however, no major sub-Saharan African or European influence was found. This result contrasts with the high amount of sub-Saharan and Eurasian maternal lineages previously described in Tunisia. Overall, our results reveal a certain genetic inter-population diversity, especially among Berber groups, and sexual asymmetry, paternal lineages being mostly of autochthonous origin. In addition, Andalusians, who are supposed to be migrants from southern Spain, do not exhibit any substantial contribution of European lineages, suggesting a North African origin for this ethnic group.

Genome-Wide and Paternal Diversity Reveal a Recent Origin of Human Populations in North Africa

“…The YCC nomenclature [47] was used throughout the manuscript. The Tunisian populations [39] were pooled into one group since Analysis of the Molecular Variance (AMOVA) showed them to be genetically homogeneous (variation among groups  = 0.70%, p>0.05 and 1.50%, p>0.05 for Y-STR and Y-SNP, respectively).…”

“…J2 is very frequent in the Levant/Anatolia/Iran region [37] and its spread in the Mediterranean is believed to have been facilitated by the maritime trading culture of the Phoenicians (1550 BC- 300 BC) [38]. In contrast to the Middle Eastern influence, studies have reported only limited contribution of sub-Saharan paternal lineages to the North African gene pool [39], [40]. Previous analyzes of mtDNA lineages in North African populations suggest significant Eurasian origins [41]–[43] with lineages dating back to Paleolithic times [41] and with recent gene flow from sub-Saharan Africa linked to slave trade [44].…”

From Arabia to Iberia: A Y chromosome perspective

“…Northwest Africa (100% in the Berber group from Chenini-Douiret and Jradou, Tunisia; 80% in Mozabite Berbers from Algeria; 76% in Saharawis from Western Sahara; 65-73% in Berbers from Morocco) (Arredi et al, 2004;Cruciani et al, 2004;Semino et al, 2004;Robino et al, 2008;Fadhlaoui-Zid et al, 2011) while their frequencies decline sharply towards the east (5% in North Egypt) as Berber groups (Sengupta et al, 2006) dwindle. In…”

Genetic structure of theKuwaiti population revealed by paternal lineages

“…Based on haplogroup distribution, the genetic pool of the North African populations is made up of two components: the Berber genetic impact of the autochthonous inhabitants of the region (haplogroup E-M81) added to the Arabic one (haplogroup J1-M267), brought to North Africa by gene flow from the Middle East (Fadhlaoui-Zid et al, 2011;Robino et al, 2008;TrikiFendri et al, 2015). In fact, it is well known that the distribution of E-M81 in Africa is highly related to the regions inhabited by Berber-speaking populations, suggesting a close haplogroup-ethnic group parallelism (Cruciani et al, 2004).…”