A Response to Tracing Modern Human Origins

Both modern human mitochondrial DNA (mtDNA) and the male-specific part of the modern human Y chromosome have a recent origin in Africa and were dispersed throughout the rest of the world less than 100,000 years ago (1, 2). This is not to say that there was no (limited) interbreeding of anatomically modern humans with archaic humans, which might be reflected in some autosomal and X-chromosome genes—a possibility that our Report did not address. The current evidence from these loci, however, remains equivocal.