Proteomic identification and evolutionary analysis of primate reproductive proteins

Abstract

Sex and reproduction have long been recognized as drivers of distinct evolutionary phenotypes. Studying the evolution and molecular variation of reproductive proteins can provide insights into how primates have evolved and adapted due to sexual pressures. In this dissertation, I explore the long-term evolution of reproductive proteins in human and non-human primates. I first describe the evolutionary diversification of sperm and eggs, and what drives them to diverge. I then describe rapidly evolving proteins in the egg and in sperm-egg interactions. I then present the use of a unique combination of genomic and proteomic technologies to study the evolution of seminal fluid proteins. With proteomics, I identify and quantify the abundance of a large proportion of uncharacterized seminal fluid proteins from 8 primate species with diverse mating systems. Using evolutionary analyses, I find rapidly evolving seminal fluid proteins and candidates genes with evolutionary rates and protein abundances that are correlated with mating system variation. I then explore the phylogentic relationships between putatively coevolving sperm-egg fusion genes. I find evidence that two pairs of sperm-egg fusion genes have correlated evolutionary rates along primate phylogenetic branches, which may indicate that they are genetically interacting. I conclude by discussing how to disentangle the selective pressures causing reproductive protein divergence, the value of using proteomics in comparative evolutionary studies, and future directions for identifying interacting fertilization proteins.