Temporal trails of natural selection in human mitogenomes.
Mildly deleterious mutations initially contribute to the diversity of a population, but later they are selected against at high frequency and are eliminated eventually. Using over 1,500 complete human mitochondrial genomes along with those of Neanderthal and Chimpanzee, I provide empirical evidence for this prediction by tracing the footprints of natural selection over time. The results show a highly significant inverse relationship between the ratio of nonsynonymous-to-synonymous divergence (d(N)/d(S)) and the age of human haplogroups. Furthermore, this study suggests that slightly deleterious mutations constitute up to 80% of the mitochondrial amino acid replacement mutations detected in human populations and that over the last 500,000 years these mutations have been gradually removed.
Subramanian
Sankar
S
Allan Wilson Centre for Molecular Ecology and Evolution, Institute of Molecular BioSciences, Massey University, Auckland, New Zealand. s.subramanian@griffith.edu.au
D000818:Animals; D019143:Evolution, Molecular; D054629:Genome, Mitochondrial; D006801:Humans; D009154:Mutation; D012641:Selection, Genetic