A burst of protein sequence evolution and a prolonged period of asymmetric evolution follow gene duplication in yeast

It is widely accepted that newly arisen duplicate gene pairs experience all altered selective regime that is often manifested as all increase ill the rate of protein sequence evolution. Marly details about the nature of the rate acceleration remain unknown, however, including its typical magnitude and duration, and whether it applies to both gene copies or just one. We provide initial answers to these questions by comparing the rate of protein sequence evolution among eight yeast species, between a large set of duplicate gene pairs that were created by a whole-genome duplication (WGD) and a set of genes that were returned to single-copy after this event. Importantly, we use a new method that takes into account the tendency for slowly evolving genes to be retained preferentially ill duplicate. We show that, oil average, proteins encoded by duplicate gene pairs evolved at least three times faster immediately after the WGD than single-copy genes to which they behave identically ill non-WGD lineages. Although the high rate ill duplicated genes subsequently declined rapidly, it has not yet returned to the typical rate for single-copy genes. Ill addition, we show that although duplicate gene pairs often have highly asymmetric rates of evolution, even the slower members of pairs show evidence of a burst of protein sequence evolution immediately after duplication. We discuss the contribution Of neofunctionlization to duplicate gene preservation and propose that a form of subfunctionalization mediated by coding region activity-reducing mutations is likely to have played all important role.