Mapping human dispersals into the Horn of Africa from Arabian Ice Age refugia using mitogenomes

"Article number: 25472"
Rare mitochondrial lineages with relict distributions can sometimes be disproportionately informative about deep events in human prehistory. We have studied one such lineage, haplogroup R0a, which uniquely is most frequent in Arabia and the Horn of Africa, but is distributed much more widely, from Europe to India. We conclude that: (1) the lineage ancestral to R0a is more ancient than previously thought, with a relict distribution across the Mediterranean/Southwest Asia; (2) R0a has a much deeper presence in Arabia than previously thought, highlighting the role of at least one Pleistocene glacial refugium, perhaps on the Red Sea plains; (3) the main episode of dispersal into Eastern Africa, at least concerning maternal lineages, was at the end of the Late Glacial, due to major expansions from one or more refugia in Arabia; (4) there was likely a minor Late Glacial/early postglacial dispersal from Arabia through the Levant and into Europe, possibly alongside other lineages from a Levantine refugium; and (5) the presence of R0a in Southwest Arabia in the Holocene at the nexus of a trading network that developed after ~3 ka between Africa and the Indian Ocean led to some gene flow even further afield, into Iran, Pakistan and India.
This work was supported by the University of Pavia strategic theme “Towards a governance model for international migration: an interdisciplinary and diachronic perspective” (MIGRAT-IN-G), the Italian Ministry of Education, University and Research: Progetti Futuro in Ricerca 2012 (RBFR126B8I) (to A.A. and A.O.) and Progetti Ricerca Interesse Nazionale 2012 (to A.A., F.C., A.T. and O.S.), a Leverhulme Doctoral Scholarship award to M.B.R., a Newton International Fellowship to M.P., the intramural funding program of the Medical University Innsbruck for young scientists MUI-START, Project 2013042025 (to M.B.), an EMBO short-term fellowship (ASTF 70- 2014/Award) and a University of Huddersfield University Research Fellowship award to F.G. P.S. is supported by FCT, European Social Fund, Programa Operacional Potencial Humano and the FCT Investigator Programme (IF/01641/2013) and acknowledges FCT I.P. for CBMA’s strategic funding UID/BIA/04050/2013.