The phylogeography of mitochondrial DNA haplogroup L3g in Africa and the Atlantic slave trade. Reply to Bortolini et al.

The availability of new mtDNA data from central Africa has allowed Bortolini et al. (2004 [in this issue]) to evaluate two alternative scenarios, formulated by Salas et al. (2004), regarding the source of the L3g mtDNAs carried from Africa to America by the Atlantic slave trade. Bortolini et al. proposed that the American L3g haplotypes have an Atlantic African provenance, rather than a direct eastern African origin, and that their most likely source was Cameroon or the neighboring regions. We can safely rule out the Atlantic coast of western Africa as an important source for American L3g, since this haplogroup has not been detected at present in a large sample (>1,200 mtDNAs) that includes individuals from, among other places, Cabo Verde, Senegal, Sierra Leone, and Nigeria. Some diffusion into northern Africa (Egypt, with signatures in Sudan and Nubia) as well as into the Middle East (Syria, Israel, and Palestine) has been detected, probably reflecting the haplogroup’s greater antiquity in eastern Africa.