MISMATCH DISTRIBUTIONS OF MTDNA REVEAL RECENT HUMAN-POPULATION EXPANSIONS

Although many genetic studies of human evolution have tried to make di stinctions between the replacement and the multiregional evolution hyp otheses, current methods and data have not resolved the issue. However , new advances in nucleotide divergence theory can complement these in vestigations with a description of human demographic behavior during t he late Middle and Upper Paleolithic (approximately the last 250,000 y ears). Restriction fragment length polymorphism (RFLP) and DNA sequenc e analyses of human mitochondrial DNAs (mtDNAs) from 25 ethnic and rac ial groups indicate that significant expansions occurred during the la te Middle and Upper Paleolithic in 23 of the 25 populations examined. Estimates for the individual group expansion times are consistently le ss than 100,000 years ago with a mean expansion time of approximately 40,000 years ago. The dramatic expansions suggested by these data occu rred well after modern human anatomy appeared, approximately 100,000 y ears ago, but are concordant with archeological evidence for the expan sion of modern human technology, approximately 50,000 years ago.