Direct estimation of mutations in great apes reveals significant recent human slowdown in the yearly mutation rate

Abstract

The human mutation rate per generation estimated from trio sequencing has revealed an almost linear relationship with the age of the father and the age of the mother. The yearly trio-based mutation rate estimate of ~0.43x10-9 is markedly lower than prior indirect estimates of ~1x10-9 per year from phylogenetic comparisons of the great apes. This suggests either a slowdown over the past 10 million years or an inaccurate interpretation of the fossil record. Here we use sequencing of chimpanzee, gorilla and orangutan trios and find that each species has higher estimated mutation rates per year by factors of 1.67+/- 0.22, 1.54+/- 0.2 and 1.84+/- 0.19, respectively. These estimates suggest a very recent and appreciable slowdown in human mutation rate, and, if extrapolated over the great apes phylogeny, yields divergence estimates much more in line with the fossil record and the biogeography.