title: A recent common ancestry for human Y chromosomes.
abstract: The male-specific portion of the Y chromosome is especially useful for studies of human origins. Patterns of nucleotide variation that are neutral with respect to fitness should permit estimates of when and where ancestral Y chromosomes existed. However, variation on the human Y chromosome has been observed to be greatly reduced relative to the autosomes and the X chromosome. One explanation is that selection for a favourable mutation on the non-recombining portion of the Y chromosome has resulted in the recent fixation of a single Y haplotype. A 2.6-kilobase fragment encompassing a polymorphic Alu insertion was sequenced from 16 human and four chimpanzee Y chromosomes. Patterns of nucleotide sequence diversity and divergence provide no evidence for a recent, strong selective sweep on the human Y chromosome. The time back to a common ancestral human Y chromosome is estimated to be 188,000 years, with a 95% confidence interval from 51,000 to 411,000 years. These results are consistent with autosomal and mitochondrial DNA studies that suggest a long-term human effective population size of 10,000 and a sex ratio of 1 (ref. 7). These inferences contradict predictions of the multiregional hypothesis positing a widespread transformation of Homo erectus populations into Homo sapiens.
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D019143:Evolution, Molecular; D006239:Haplotypes; D015186:Hominidae; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D002679:Pan troglodytes; D011110:Polymorphism, Genetic; D014998:Y Chromosome
chemical_list: D017931:DNA Primers