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

与性发育有关的基因和基因通路在动物分类群中高度保守；像人类、鱼类和苍蝇这样不同的生物，在决定个体发育为雌性还是雄性时，具有一些相同的基本组成部分。本研究将探讨两种鱼类性发育的遗传基础。在大多数动物中，性别是由基因决定的，在发育过程中确定，并终身固定。然而，这种模式并不正确，因为许多鱼类表现出改变其功能性性别的非凡能力（称为雌雄同体）。个体既不是雌性也不是雄性，成年后可以在产生精子和卵子之间转换。我们对改变性功能的基因基础知之甚少。了解雌雄同体鱼类在其一生中产生新组织以产生精子和卵子的能力，可以为解决人类的生育问题提供重要信息，因为人类没有这种能力。此外，根据研究结果，研究人员将为中小学生提供课堂教材。顺序雌雄同体，即成年后配子类型之间转换的能力，在硬骨鱼中是一种普遍的策略。本研究旨在了解海洋鱼类虾蛄科（Gobiidae）性功能变化的发展、进化和多样化。这个家族是探索性可塑性进化和发展的理想系统，因为雌雄同体已经独立出现了多达五次。本研究将比较两种植物，红腹鱼（Eviota epiphanes）和水仙（Lythrypnus dalliI）。组织学技术将用于生成鱼类性腺从卵子到精子生产转变的形态学时间序列，并对其转变过程中大脑和性腺组织的全转录组（RNAseq）进行测序。这些数据将用于构建基因共表达网络，并将在两个物种之间进行比较。该研究结果将提供对控制性别变化过程的基因调控途径的深入了解，并用于测试这些途径中的进化守恒或变化。

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.