The Levant versus the Horn of Africa: Evidence for Bidirectional Corridors of Human Migrations

Abstract

Paleoanthropological evidence indicates that both the Levantine corridor and the Horn of Africa served, repeatedly, as migratory corridors between Africa and Eurasia. We have begun investigating the roles of these passageways in bidirectional migrations of anatomically modern humans, by analyzing 45 informative biallelic markers as well as 10 microsatellite loci on the nonrecombining region of the Y chromosome (NRY) in 121 and 147 extant males from Oman and northern Egypt, respectively. The present study uncovers three important points concerning these demic movements: (1) The E3b1-M78 and E3b3-M123 lineages, as well as the R1*-M173 lineages, mark gene flow between Egypt and the Levant during the Upper Paleolithic and Mesolithic. (2) In contrast, the Horn of Africa appears to be of minor importance in the human migratory movements between Africa and Eurasia represented by these chromosomes, an observation based on the frequency distributions of E3b*-M35 (no known downstream mutations) and M173. (3) The areal diffusion patterns of G-M201, J-12f2, the derivative M173 haplogroups, and M2 suggest more recent genetic associations between the Middle East and Africa, involving the Levantine corridor and/or Arab slave routes. Affinities to African groups were also evaluated by determining the NRY haplogroup composition in 434 samples from seven sub-Saharan African populations. Oman and Egypt's NRY frequency distributions appear to be much more similar to those of the Middle East than to any sub-Saharan African population, suggesting a much larger Eurasian genetic component. Finally, the overall phylogeographic profile reveals several clinal patterns and genetic partitions that may indicate source, direction, and relative timing of different waves of dispersals and expansions involving these nine populations.

Separating the post-Glacial coancestry of European and Asian Y chromosomes within haplogroup R1a

“…All chromosomes unresolved previously beyond the R1-M173* level 14,15,35,36 that were available to us are now attributed to either R1a*-M420 or R1b*-M343 haplogroups. Consequently, we revise the haplogroup nomenclature following the YCC guidelines.…”

The phylogenetic and geographic structure of Y-chromosome haplogroup R1a

“…We assembled a genotyping panel of 16 244 males from 126 Eurasian populations, some of which we report upon for the first time herein and others that we have combined from earlier studies, 22,[29][30][32][33][34][35][36][37][38][39][40][41][42][43][44][45] and updated to a higher level of phylogenetic resolution. All samples were obtained using locally approved informed consent and were de-identified.…”

The genetic landscape of Equatorial Guinea and the origin and migration routes of the Y chromosome haplogroup R-V88

“…Nevertheless, high frequencies of these lineages in some African populations have been previously reported by several authors. [5][6][7]29,30 Lineages in clade A, although almost entirely restricted to Africa, have been described in Bantu populations at low frequencies. These lineages are mostly present in Nilo-Saharan speakers Figure 1 Phylogenetic tree of the Y chromosome haplogroups studied.…”

“…[5][6][7]29,30 This haplogroup is thought to have originated in Central Asia approximately 40 000 years BP and then migrated westward into Europe, achieving its highest frequencies in the western region of this continent. 39,40 Although Balaresque et al 41 proposed the hypothesis of a European spread of haplogroup R1b1b2-M269 during the Neolithic, the distribution of the M269 sub-haplogroups and their Y-STR diversities proved to be compatible with a pre-Neolithic diffusion of M269 in Europe.…”