Selection on the genomic diversity of a species increases with the population size
The rate of genomic adaptation is determined by the rate of environmental change, the availability of beneficial mutations, and the efficiency of positive selection. Scientists conclude that the impact of selection on the genomic diversity of a species increases with the effective population size, most likely due to the differential influx rate of beneficial mutations.
The rate of genomic adaptation is determined by the rate of environmental change, the availability of beneficial mutations, and the efficiency of positive selection. The relative importance of these factors has been actively discussed.
A new study published this week at PNAS by Tomàs Marquès-Bonet and collaborators address these questions using whole genome sequences of great apes, which have very different population sizes whereas their genomic architectures are highly similar.
Scientists conclude that the impact of selection on the genomic diversity of a species increases with the effective population size, most likely due to the differential influx rate of beneficial mutations. This explanation is, among other possibilities, expected if adaptive evolution is limited by the waiting time for new favorable mutations in great apes.
Reference Article: Nam, K.; Munch, K.; Mailund, T.; Nater, A.; Greminger, M.P.; Krützen, M.; Marquès-Bonet, T.; Schierup, M.H. 2017. Evidence that the rate of strong selective sweeps increases with population size in the great apes. Proc Natl Acad Sci U S A. pii: 201605660. doi: 10.1073/pnas.1605660114. [Epub ahead of print]