Positive selection drives a correlation between non-synonymous/synonymous divergence and functional divergence

摘要

Motivation: Functional divergence among proteins is often assumed to be strongly influenced by natural selection, as inferred from the ratio of non-synonymous nucleotide divergence (d_N) to synonymous nucleotide divergence (d_S). That is, the more a mutation changes protein function, the more likely it is to be either selected against or selectively favored, and because the d_N/d_S ratio is a measure of natural selection, this ratio can be used to predict the degree of functional divergence (d_F). However, these hypotheses have rarely been experimentally tested.