MITOCHONDRIAL FOOTPRINTS OF HUMAN EXPANSIONS IN AFRICA

mtDNA studies support an African origin for modern Eurasians, but expa nsion events within Africa have not previously been investigated. We h ave therefore analyzed 407 mtDNA control-region sequences from 13 Afri can ethnic groups. A number of sequences (13%) were highly divergent a nd coalesced on the ''mitochondrial Eve'' in Africans. The remaining s equences also ultimately coalesced on this sequence but fell into four major clusters whose starlike phylogenies testify to demographic expa nsions. The oldest of these African expansions dates to similar to 60, 000-80,000 years ago. Eurasian sequences are derived from essentially one sequence within this ancient cluster, even though a diverse mitoch ondrial pool was present in Africa at the time.