Affordable Access

Molecular Population Genetics of the Gene Encoding the Human Fertilization Protein Zonadhesin Reveals Rapid Adaptive Evolution

Authors
Publisher
The American Society of Human Genetics
Publication Date
Source
PMC
Keywords
  • Article
Disciplines
  • Biology
  • Mathematics

Abstract

A hallmark of positive selection (adaptive evolution) in protein-coding regions is a dN/dS ratio >1, where dN is the number of nonsynonymous substitutions/nonsynonymous sites and dS is the number of synonymous substitutions/synonymous sites. Zonadhesin is a male reproductive protein localized on the sperm head, comprising many domains known to be involved in cell-cell interaction or cell adhesion. Previous studies have shown that VWD domains (homologous to the D domains of the von Willebrand factor) are involved directly in binding to the female zona pellucida (ZP) in a species-specific manner. In this study, we sequenced 47 coding exons in 12 primate species and, by using maximum-likelihood methods to determine sites under positive selection, we show that VWD2, membrane/A5 antigen mu receptor, and mucin-like domains in zonadhesin are rapidly evolving and, thus, may be involved in binding to the ZP in a species-specific manner in primates. In addition, polymorphism data from 48 human individuals revealed significant polymorphism-to-divergence heterogeneity and a significant departure from equilibrium-neutral expectations in the frequency spectrum, suggesting balancing selection and positive selection occurring in zonadhesin (ZAN) within human populations. Finally, we observe adaptive evolution in haplotypes segregating for a frameshift mutation that was previously thought to indicate that ZAN was a potential pseudogene.

There are no comments yet on this publication. Be the first to share your thoughts.