mtDNA variation in East Africa unravels the history of afro-asiatic groups
Version of Record online: 3 JAN 2013
Copyright © 2013 Wiley Periodicals, Inc.
American Journal of Physical Anthropology
Volume 150, Issue 3, pages 375–385, March 2013
How to Cite
Boattini, A., Castrì, L., Sarno, S., Useli, A., Cioffi, M., Sazzini, M., Garagnani, P., De Fanti, S., Pettener, D. and Luiselli, D. (2013), mtDNA variation in East Africa unravels the history of afro-asiatic groups. Am. J. Phys. Anthropol., 150: 375–385. doi: 10.1002/ajpa.22212
- Issue online: 23 FEB 2013
- Version of Record online: 3 JAN 2013
- Manuscript Accepted: 19 NOV 2012
- Manuscript Received: 11 JUL 2012
- University of Bologna RFO grants 2010 and 2011 to DL
- Horn of Africa;
- genetic structure
East Africa (EA) has witnessed pivotal steps in the history of human evolution. Due to its high environmental and cultural variability, and to the long-term human presence there, the genetic structure of modern EA populations is one of the most complicated puzzles in human diversity worldwide. Similarly, the widespread Afro-Asiatic (AA) linguistic phylum reaches its highest levels of internal differentiation in EA. To disentangle this complex ethno-linguistic pattern, we studied mtDNA variability in 1,671 individuals (452 of which were newly typed) from 30 EA populations and compared our data with those from 40 populations (2970 individuals) from Central and Northern Africa and the Levant, affiliated to the AA phylum. The genetic structure of the studied populations—explored using spatial Principal Component Analysis and Model-based clustering—turned out to be composed of four clusters, each with different geographic distribution and/or linguistic affiliation, and signaling different population events in the history of the region. One cluster is widespread in Ethiopia, where it is associated with different AA-speaking populations, and shows shared ancestry with Semitic-speaking groups from Yemen and Egypt and AA-Chadic-speaking groups from Central Africa. Two clusters included populations from Southern Ethiopia, Kenya and Tanzania. Despite high and recent gene-flow (Bantu, Nilo-Saharan pastoralists), one of them is associated with a more ancient AA-Cushitic stratum. Most North-African and Levantine populations (AA-Berber, AA-Semitic) were grouped in a fourth and more differentiated cluster. We therefore conclude that EA genetic variability, although heavily influenced by migration processes, conserves traces of more ancient strata. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.