Complex Evolutionary Genetics of Gonadal Differentiation in a Classic Model of Behavior, Astatotilapia burtoni

适当的性腺分化是绝对的基础，以适应性繁殖的物种，但令人惊讶的多样性存在于物种之间的机制，决定男性与女性。遗传性别决定是一种常见的机制，但很少有人知道新的性别决定基因是如何出现的，相互作用，并在人群中进化。从历史上看，遗传性别决定研究主要集中在少数单因素，染色体性别决定系统。最近，遗传性别决定已被映射在一组更广泛的物种，揭示了性别决定基因在各种染色体背景下的多样性目录。多基因性别决定（PSD）也已被证实在多个分类群，其中多个遗传因素指导性发育。PSD挑战了关于遗传性别决定系统的传统思维，同时提供了强有力的策略来探索性别决定的进化和发展，包括比较具有多种性别决定遗传模式的兄弟姐妹。换句话说，虽然PSD物种的个体发育为雄性或雌性，但可能存在几种遗传类型的雄性和雌性。丽鱼科鱼类Astatotilapia burtoni使用PSD来确定雄性与雌性发育，为理解遗传性别决定的进化和发展提供了模型。这项工作的目的是提供最全面的分析PSD系统的日期，使用A。Burtoni作为一个模型系统。该项目将揭示驱动性腺分化和发育的新基因和基因网络，同时产生重要的进化见解。这项研究还将为A. Burtoni，神经和行为生物学模型。本科生和研究生以及博士后研究员将进行拟议的实验，为他们在科学领域的职业生涯做准备。此外，K-12教师将通过研究人员和凯南研究员计划的共同指导获得直接的研究经验，共同开发广泛适用于州教室，区域公共宣传场所和万维网的教育材料。burtoni，产生许多基因型的性别和机会，研究多个性别决定基因的相互作用的个人。拟议的研究采用综合方法，涉及遗传作图，基因组组装和性染色体注释，比较基因组学和性腺分化过程中的基因网络分析。目的包括多个新的性别决定基因的定位和功能测试，以及追踪新的性别决定等位基因对它们所在的染色体结构的进化影响，包括连锁基因的功能进化。通过性发育的基因表达分析将补充这些映射和注释工作，并提供了解如何在发展过程中整合多个遗传性别开关。在发育过程中不同遗传性别之间的基因表达分析也将揭示性腺发育的核心遗传网络，并深入了解遗传网络如何演变，而不会对不可或缺的复杂性状产生负面影响。自从A. burtoni是一个长期存在的行为模型，它为分析第二性征提供了极好的背景，包括现有的行为基因表达数据，以及与物种中存在的各种性别决定模式有关的数据。

Proper gonadal differentiation is absolutely fundamental to the fitness of sexually reproducing species, yet surprising diversity exists among species in the mechanisms that determines males vs. females. Genetic sex determination is one common mechanism, yet little is known about how novel sex determination genes arise, interact, and evolve in populations. Historically, genetic sex determination research has largely focused on a handful of single-factor, chromosomal sex determination systems. More recently, genetic sex determination has been mapped in a broader set of species, revealing a diverse catalog of sex determination genes in a variety of chromosomal contexts. Polygenic sex determination (PSD) has also been confirmed in multiple taxa, where multiple genetic factors direct sexual development. PSD challenges traditional thinking regarding genetic sex determination systems, while providing powerful strategies to explore the evolution and development of sex determination, including comparisons of siblings with multiple genetic modes of sex determination. In other words, while individuals of species with PSD develop as male or female, several genetic types of males and females may exist. The cichlid fish species Astatotilapia burtoni uses PSD to determine male vs. female development, providing a model to understand the evolution and development of genetic sex determination. This work aims to provide the most comprehensive analysis of a PSD system to date, using A. burtoni as a model system. The project should reveal novel genes and gene networks driving gonadal differentiation and development, while yielding important evolutionary insights. The research will also produce important genome resources for A. burtoni, a model for neural and behavioral biology. Undergraduate and graduate students and postdoctoral fellows will carry out proposed experiments, preparing them for careers in science. Additionally, K-12 teachers will be given direct research experience through co-mentoring by the researchers and the Kenan Fellows Program, together developing educational materials broadly scaled for state classrooms, regional public outreach venues, and the world wide web.Multiple sex determination loci segregate in A. burtoni, producing many genotypic sexes and the opportunity to study the interaction of multiple sex determination genes within individuals. The proposed research uses an integrated approach involving genetic mapping, genome assembly and annotation of sex chromosomes, comparative genomics, and gene network analysis during gonadal differentiation. Aims include mapping and functional testing of multiple novel sex determination genes, and tracing the evolutionary impact of novel sex determination alleles on the structure of chromosomes where they reside, including functional evolution of linked genes. Gene expression analyses through sexual development will supplement these mapping and annotation efforts, and provide understanding of how multiple genetic sex switches are integrated during development. Gene expression analyses among different genetic sexes during development will also reveal core genetic networks underlying gonadal development, and yield insight into how genetic networks evolve without negatively impacting indispensable complex traits. Since A. burtoni is a longstanding behavior model, it provides excellent context for analysis of secondary sexual characteristics, including existing behavioral gene expression data, in relation to the various modes of sex determination present in the species.