Pervasive Adaptive Evolution in Mammalian Fertilization Proteins

Willie J. Swanson, Rasmus Nielsen, Qiaofeng Yang
2003 Molecular biology and evolution  
Mammalian fertilization exhibits species specificity, and the proteins mediating sperm-egg interactions evolve rapidly between species. In this study, we demonstrate that the evolution of seven genes involved in mammalian fertilization is promoted by positive Darwinian selection by using likelihood ratio tests (LRTs). Several of these proteins are sperm proteins that have been implicated in binding the mammalian egg coat zona pellucida glycoproteins, which were shown previously to be subjected
more » ... ly to be subjected to positive selection. Taken together, these represent the major candidates involved in mammalian fertilization, indicating positive selection is pervasive amongst mammalian reproductive proteins. A new LRT is implemented to determine if the d N /d S ratio is significantly greater than one. This is a more refined test of positive selection than the previous LRTs which only identified if there was a class of sites with a d N /d S ratio Ͼ1 but did not test if that ratio was significantly greater than one.
doi:10.1093/oxfordjournals.molbev.a004233 pmid:12519901 fatcat:zvsvur5nffcp3marqzbiqgu64i