Direct estimate of the spontaneous germ line mutation rate in African green monkeys

Here, I provide the first direct estimate of the spontaneous mutation rate in an Old World monkey, using a seven individual, three-generation pedigree of African green monkeys. Eight de novo mutations were identified within ∼1.5 Gbp of accessible genome, corresponding to an estimated point mutation rate of 0.94 × 10^-8 per site per generation, suggesting an effective population size of ∼12000 for the species. This estimation represents a significant improvement in our knowledge of the population genetics of the African green monkey, one of the most important nonhuman primate models in biomedical research. Furthermore, by comparing mutation rates in Old World monkeys with the only other direct estimates in primates to date-humans and chimpanzees-it is possible to uniquely address how mutation rates have evolved over longer time scales. While the estimated spontaneous mutation rate for African green monkeys is slightly lower than the rate of 1.2 × 10^-8 per base pair per generation reported in chimpanzees, it is similar to the lower range of rates of 0.96 × 10^-8 -1.28 × 10^-8 per base pair per generation recently estimated from whole genome pedigrees in humans. This result suggests a long-term constraint on mutation rate that is quite different from similar evidence pertaining to recombination rate evolution in primates.