Exon capture data uncover the determiants of the adaptive substitution rate in eukaryotes

We gathered multi-species, coding sequence polymorphism data in five distant groups of animals via exon capture (butterflies, ants, earth worms, ribbon worms, mussels). We estimated the expected rate of nearly-neutral amino-acid substitution in each group by jointly analysing the synonymous and non-synonymous SFS of closely related species. Surprisingly, the improved method revealed a negative relationship between wA and Ne across groups, i.e., a faster rate of adaptive molecular evolution in small populations.