June 15, 2014

Chimp mutation rate is equal to human mutation rate but driven more by males

This is important because (a) it shows evidence for the "slow" mutation rate in a species related to humans, (b) it shows that chimp and human mutation rates are equal and so using the human mutation rate in studies of divergence with chimps is justified, and (c) it is driven differently by males/females than in humans.

Science 13 June 2014: Vol. 344 no. 6189 pp. 1272-1275
DOI: 10.1126/science.344.6189.1272

Strong male bias drives germline mutation in chimpanzees

Oliver Venn


Germline mutation determines rates of molecular evolution, genetic diversity, and fitness load. In humans, the average point mutation rate is 1.2 × 10−8 per base pair per generation, with every additional year of father’s age contributing two mutations across the genome and males contributing three to four times as many mutations as females. To assess whether such patterns are shared with our closest living relatives, we sequenced the genomes of a nine-member pedigree of Western chimpanzees, Pan troglodytes verus. Our results indicate a mutation rate of 1.2 × 10−8 per base pair per generation, but a male contribution seven to eight times that of females and a paternal age effect of three mutations per year of father’s age. Thus, mutation rates and patterns differ between closely related species.



eurologist said...

Had the authors used the much more logical mutation rate by age (rather than generation), there may not have been any significant discrepancy between humans and chimps.

Autosomal mutations have long been known to be dominated by males, and thus by age, and not by generation.

Apes' generation length is much shorter, so the fallacy of using generation length rather than age is even more consequential regarding this completely unscientific result, with them.

andrew said...

The relative male v. female contribution to mutations isn't all that different. In humans males are also grossly disproportionately the source of mutations. In humans, 85% of mutations are male in origin.

The 90% rate for chimps, given the margin of error in both the human and chimp measurements, may not even be a statistically significant difference.