DISSERTATION RESEARCH: Exploring the Evolution of Shifts in Reproductive Function in Hermaphroditic Fishes Using Gene Coexpression Networks

点击翻译按钮获取中文摘要

Genes and gene pathways responsible for sexual development are highly conserved across animal taxa; organisms as different as humans, fishes, and flies share some of the same basic building blocks for determining if an individual develops as a female or a male. This study will investigate the genetic basis of sexual development in two species of fish. In most animals, sex is predetermined by genetics, established during development, and is fixed for life. This pattern is not true, however, for numerous fish species that exhibit the remarkable ability to change their functional sex (referred to as hermaphroditism). Individuals are neither female nor male and can shift between producing both sperm and eggs as adults. We know very little about the genetic bases of shifting sexual function. Understanding the ability of hermaphroditic fishes to produce new tissues for generating sperm and ova throughout their lives could provide vital information for solving fertility issues in humans, who do not have this ability. In addition, based on the findings, the researchers will provide classroom material for elementary and middle school students.Sequential hermaphroditism, the ability to transition between gamete types at some point in adult life, is a widespread strategy among teleost fishes. This study aims to understand the development, evolution and diversification of shifts in sexual function in the marine fish family Gobiidae. This family is an ideal system in which to explore both the evolution and development of sexual plasticity, as hermaphroditism has arisen independently as many as five times. The study will compare two species, Eviota epiphanes with Lythrypnus dalliI. Histological techniques will be used to generate a morphological time series of fish gonads as they transition from ova to sperm production and sequence the whole transcriptome (RNAseq) of brain and gonadal tissue as they transition. These data will be used to construct gene coexpression networks that will be compared between the two species. The results will provide insight into the gene regulatory pathways that govern the sex change process and be used to test for evolutionary conservation or change in those pathways.