Mating systems and protein-protein interactions determine evolutionary rates of primate sperm proteins.

Bibliographic Collection: 
Publication Type: Journal Article
Authors: Schumacher, Julia; Rosenkranz, David; Herlyn, Holger
Year of Publication: 2014
Journal: Proc Biol Sci
Volume: 281
Issue: 1775
Pagination: 20132607
Date Published: 2014 Jan 22
Publication Language: eng
ISSN: 1471-2954
Keywords: Animals, DNA, Complementary, Evolution, Molecular, Haplorhini, Male, Mating Preference, Animal, Protein Interaction Domains and Motifs, Sequence Analysis, DNA, Sexual Behavior, Animal, Spermatozoa, Testis

To assess the relative impact of functional constraint and post-mating sexual selection on sequence evolution of reproductive proteins, we examined 169 primate sperm proteins. In order to recognize potential genome-wide trends, we additionally analysed a sample of altogether 318 non-reproductive (brain and postsynaptic) proteins. Based on cDNAs of eight primate species (Anthropoidea), we observed that pre-mating sperm proteins engaged in sperm composition and assembly show significantly lower incidence of site-specific positive selection and overall lower non-synonymous to synonymous substitution rates (dN/dS) across sites as compared with post-mating sperm proteins involved in capacitation, hyperactivation, acrosome reaction and fertilization. Moreover, database screening revealed overall more intracellular protein interaction partners in pre-mating than in post-mating sperm proteins. Finally, post-mating sperm proteins evolved at significantly higher evolutionary rates than pre-mating sperm and non-reproductive proteins on the branches to multi-male breeding species, while no such increase was observed on the branches to unimale and monogamous species. We conclude that less protein-protein interactions of post-mating sperm proteins account for lowered functional constraint, allowing for stronger impact of post-mating sexual selection, while the opposite holds true for pre-mating sperm proteins. This pattern is particularly strong in multi-male breeding species showing high female promiscuity.

DOI: 10.1098/rspb.2013.2607
Alternate Journal: Proc. Biol. Sci.