The Nature and Phylogenomic Impact of Sequence Convergence

Protein sequence convergence refers to substitutions leading to the same amino acid residue at the same position of a protein in multiple independent evolutionary lineages. Protein sequence convergence is often viewed as adaptive signal so is of great interest to evolutionary biologists. In this article, we review complications in identifying sequence convergences, statistical tests of the null hypothesis that the observed convergence events in a protein are attributable to chance alone, interpretations of genome-wide observations of sequence convergence, and a comparison in the susceptibility of molecular and morphological characters to convergence and its phylogenetic implications. We highlight the substantial progresses made in the last two decades and point out the main challenges at the present.