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

经典行为模型中的性腺分化的复杂进化遗传学，Astatotilapia burtoni

• 批准号: 1456765
• 负责人: Reade Roberts
• 金额: $ 78万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-15 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1456765&HistoricalAwards=false
• 关键词: Complex; Evolutionary; Genetics; Gonadal; Differentiation

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.

适当的性腺分化对有性繁殖物种的适合性是绝对基础的，但在决定男性与女性的机制上，物种之间存在着令人惊讶的多样性。遗传性别决定是一种常见的机制，但人们对新的性别决定基因如何在种群中产生、相互作用和进化知之甚少。从历史上看，基因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上。最近，遗传性别决定已经在更广泛的物种中被绘制出来，揭示了在不同染色体背景下性别决定基因的不同目录。多基因性别决定(PSD)也已在多个分类群中得到证实，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，尽管患有PSD的物种的个体发育为男性或女性，但可能存在几种男性和女性的遗传类型。伯顿罗非鱼使用PSD来确定男性和女性的发育，为理解遗传性别决定的进化和发展提供了一个模型。这项工作旨在提供迄今为止最全面的PSD系统分析，使用A.burtoni作为模型系统。该项目应该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。这项研究还将为神经和行为生物学模型伯东尼提供重要的基因组资源。本科生、研究生和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，通过研究人员和凯南研究员计划的共同指导，K-12教师将获得直接的研究经验，共同为州立课堂、地区性公共宣传场所和万维网开发广泛规模的教育材料。多个性别决定基因在A.burtoni中分离，产生许多基因类型的性别，并有机会研究多个性别决定基因在个体内的相互作用。这项研究采用了一种综合的方法，包括遗传作图、性染色体的基因组组装和注释、比较基因组学和性腺分化过程中的基因网络分析。目的包括对多个新的性别决定基因进行定位和功能测试，以及追踪新的性别决定等位基因对其所在染色体结构的进化影响，包括连锁基因的功能进化。通过性发育进行的基因表达分析将补充这些作图和注释工作，并提供对多个基因性别开关在发育过程中如何整合的理解。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在不对不可或缺的复杂特征产生负面影响的情况下进化。由于A.burtoni是一个长期存在的行为模型，它为分析第二性特征提供了很好的背景，包括与物种中存在的各种性别决定模式相关的现有行为基因表达数据。