Basal Eurasians are an inferred population that diverged from other non-Africans quite early.¹ Basal Eurasians split from hub Eurasians shortly after humans migrated out of Africa,² with estimates placing the time of divergence for Basal Eurasians from the other Eurasian lineages before 50 KYA.³ Given that this lineage has been inferred and there are therefore no individuals associated with the lineage, the primary place of residence for this population is inferred as well. The geographic location of the Basal Eurasian population has been estimated to be west of the hub, primarily in the South Levant and Arabian Peninsula; the ecological isolation caused by the harsh climate of the region would have allowed the Hub and Basal populations to diverge from each other via drift, explaining the genetic disconnect between the two populations.⁴

Subsequent Migrations

Although initially isolated, Basal Eurasians would have begun to admix with other populations by at least 25KYA.⁵ Basal Eurasian ancestry was widespread throughout subsequent populations that inhabited Western Asia and the Eastern Mediterranean , with Natufians, Mesolithic and Neolithic Iranians,⁶ and Anatolian-like populations^7,8 all possessing a significant portion of Basal Eurasian ancestry. This is exemplified by the fact that West Eurasians, who possess ancestry from these populations at varying degrees, have less Neanderthal ancestry compared to East Eurasians, which can be explained via admixture with a population with less Neanderthal ancestry, i.e. the theorized Basal Eurasians, whose genetic impact on West Eurasia is ubiquitous.⁹

Sources

¹ Hajdinjak, M., Mafessoni, F., Skov, L. et al. Initial Upper Palaeolithic humans in Europe had recent Neanderthal ancestry. Nature 592, 253-257 (2021). https://doi.org/10.1038/s41586-021-03335-3

^{2, 4, 5} Vallini, L., Zampieri, C., Shoaee, M.J. et al. The Persian plateau served as hub for Homo sapiens after the main out of Africa dispersal. Nat Commun 15, 1882 (2024). https://doi.org/10.1038/s41467-024-46161-7

^{6, 9} Lazaridis, I., Nadel, D., Rollefson, G. et al. Genomic insights into the origin of farming in the ancient Near East. Nature 536, 419–424 (2016). https://doi.org/10.1038/nature19310

⁷Lazaridis, Iosif & Belfer-Cohen, Anna & Mallick, Subhashis & Patterson, Nick & Cheronet, Olivia & Rohland, Nadin & Jakeli, Nino & Kvavadze, Eliso & Lordkipanidze, David & Matzkevich, Zinovi & Meshveliani, Tengiz & Culleton, Brendan & Kennett, Douglas & Pinhasi, Ron & Reich, David. (2018). Paleolithic DNA from the Caucasus reveals core of West Eurasian ancestry. 10.1101/423079.

⁸ Feldman, M., Fernandez-Dominguez, E., Reynolds, L. et al. Late Pleistocene human genome suggests a local origin for the first farmers of central Anatolia. Nat Commun 10, 1218 (2019). https://doi.org/10.1038/s41467-019-09209-7