Duarte, M.A., Fernandes, C.R., Heckel, G., da Luz Mathias, M. & Bastos-Silveira, C. (2021) Variation and selection in the putative sperm-binding region of ZP3 in muroid rodents: a comparison between cricetids and murines.Genes, 12(9), 1450. DOI:10.3390/genes12091450 (IF2020 4,096; Q2 Genetics and Heredity)
In mammals, the zona pellucida glycoprotein 3 (ZP3) is considered a primary sperm receptor of the oocyte and is hypothesized to be involved in reproductive isolation. We investigated patterns of diversity and selection in the putative sperm-binding region (pSBR) of mouse ZP3 across Cricetidae and Murinae, two hyperdiverse taxonomic groups within muroid rodents. In murines, the pSBR is fairly conserved, in particular the serine-rich stretch containing the glycosylation sites proposed as essential for sperm binding. In contrast, cricetid amino acid sequences of the pSBR were much more variable and the serine-rich motif, typical of murines, was generally substantially modified. Overall, our results suggest a general lack of species specificity of the pSBR across the two muroid families. We document statistical evidence of positive selection acting on exons 6 and 7 of ZP3 and identified several amino acid sites that are likely targets of selection, with most positively selected sites falling within or adjacent to the pSBR.