Pierre Zalloua

Exploration of the ancestral genetic landscape of the Saudi Peninsula and the Levant

The calamitous and abrupt weather conditions of the Yonger Dryas that left Arabia and most of the southern Levant dry were the catalysts for the Natufians’ movement from the southern Levant to the Negev, North East Levant, and Mesopotamia. Other contemporaneous cultures emerged in the Zagros, the Zawi Chemi/Shenidar and in Southern Turkey the Beldibians. Besides material remains, many of these cultures, including Natufians, left human remains whose genetic information provides a time scale of human migration and admixture starting nearly from the time of post glacial expansions from refugia to modern times.

Genomic data analyses revealed two distinct expansions dominating Southwest Asia, one leading to the Levant and the other leading to the Persian Gulf and Iran. These two genetic expansions shared a common ancestor around 46-77kya. Further studies showed that Neolithic Levant derived its ancestry from Natufian and Neolithic Anatolian populations, that subsequently admixed with the Neolithic Iranian population, all within a region defined as the Neolithic Core Zone, yielding the modern Levantine genetic landscape. Neolithic Iranians and Levantine populations also acquired lineages found among Scandinavian Hunter Gatherers long before Indo-European languages appeared in the Levant. Modern Arabian peninsula populations derived their ancestry from two genetic components: one marked by Natufian, and one component largely reflected by the Persian Gulf and modern Iran. Further, Ethiopia carries two major subpopulations (Gumuz and Somalis) each carrying distinctive genetics impacting the Peninsula, and the Levant.

David Comas

Genetic insights into the population history of North African groups

Institut de Biologia Evolutiva (CSIC-UPF), Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona

Despite being part of the African continent, the population history of North African groups has shown its own demographic characteristics. The region has been populated since Paleolithic times although posterior contacts and extensive gene flow from neighboring areas have modelled the extant North African gene pool. The genetic composition of North Africans is an amalgam of West Eurasian and sub-Saharan components, including an autochthonous component found exclusively in North Africa. This admixture of components has been shown by the analysis of classical genetic and uniparental markers, as well as recent genome-wide data. There is ample debate about the continuity of these first inhabitants and the extant groups of North Africa. Ancient genetic data and new complete genomes provide new insights into the population history of the region, suggesting that there is genetic evidence of population continuity in North Africans despite the major genetic replacement that took place during the Neolithic and the minor influence of historical events such as the Arabization. No correlation between major linguistic groups (Arabs and Berbers) and genetics is found in North Africa, but gradients of ancestral components are found in the region, suggesting a heterogeneous genetic landscape, which can be correlated with demographic events. One of the limitations of the reconstruction of the population history of North Africans is the lack of genetic data compared to other geographical areas, which challenges the availability of data for biomedical studies.