Distribution of haplotypes from a chromosome 21 region distinguishes multiple prehistoric human migrations

Despite mounting genetic evidence implicating a recent origin of modern hum ans, the elucidation of early migratory gene-flow episodes remains incomple te. Geographic distribution of haplotypes may show traces of ancestral migr ations. However, such evolutionary signatures can be erased easily by recom bination and mutational perturbations, A 565-bp chromosome 21 region near t he MX1 gene, which contains nine sites frequently polymorphic in human popu lations, has been found. It is unaffected by recombination and recurrent mu tation and thus reflects only migratory history, genetic drift, and possibl y selection, Geographic distribution of contemporary haplotypes implies dis tinctive prehistoric human migrations: one to Oceania, one to Asia and subs equently to America, and a third one predominantly to Europe. The findings with chromosome 21 are confirmed by independent evidence from a Y chromosom e phylogeny, Loci of this type will help to decipher the evolutionary histo ry of modern humans.