Mechanisms of Recurrent, Parallel Loss of X/Y Pairing and Recombination at Meiosi

Meiosi 的 X/Y 配对和重组的周期性、平行丢失的机制

• 批准号: 8679596
• 负责人: BETHANY L DUMONT
• 金额: $ 8.21万
• 依托单位: NORTH CAROLINA STATE UNIVERSITY RALEIGH
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8679596
• 关键词: Address; Aneuploidy; Architecture; Benchmarking; Biological; Biological Assay; Biological Models; Biology; Candidate Disease Gene; Chromosome Painting; Chromosome Pairing; Chromosome Segregation; Chromosomes; Clinical; Computer Analysis; Cytogenetics; Data Set; Defect; Development; Doctor of Philosophy; Ensure; Event; Evolution; Faculty; Failure; Frequencies; Gene Expression; Genes; Genetic; Genetic Predisposition to Disease; Genetic Recombination; Genome; Genomic Library; Genomics; Goals; Head; High-Throughput Nucleotide Sequencing; House mice; Human; Imagery; Infertility; Instruction; Knock-in Mouse; Laboratories; Lead; Length; Light; Link; Mammals; Meiosis; Meiotic Recombination; Mentors; Mentorship; Methods; Microtus; Mus; Mutation; North Carolina; Organism; Orthologous Gene; Pattern; Phase; Phylogeny; Postdoctoral Fellow; Process; Proteins; Pseudoautosomal Region; Quantitative Genetics; Recurrence; Research; Research Personnel; Role; Science; Sequence Analysis; Sequence Homology; Series; Sex Chromosomes; Staging; Students; Synapses; Syndrome; System; Testing; Time; Training; Training Programs; Transgenic Organisms; Trees; Turner' s Syndrome; Universities; Washington; Wisconsin; Work; X Chromosome; Y Chromosome; base; candidate identification; career; comparative; experience; functional genomics; genome sequencing; human male; innovation; innovative technologies; insight; interest; male; mammalian genome; mouse model; novel; professor; programs; public health relevance; research study; segregation; sex; skills; species difference; theories; therapeutic target; trend

DESCRIPTION (provided by applicant): I am proposing a training program that will prepare me for an independent research career in the field of evolutionary genomics. I received my PhD from the Laboratory of Genetics at the University of Wisconsin- Madison for my work on the genetic and evolutionary basis of mammalian species differences in global recombination rate. I then completed a 2-year postdoc in the Department of Genome Sciences at the University of Washington where I acquired considerable experience and proficiency in the computational analysis of large genomic datasets. Through the proposed training program, I will expand my experimental skill set to include genomic library construction, diverse cytogenetic methods, and functional analyses of candidate genes in mammalian model systems. I propose a 5-year research program composed of a 2-year phase of organized mentorship and training in the Initiative for Biological Complexity at North Carolina State University (NCSU), followed by a 3-year research phase as an independent investigator. The proposed training program will leverage cutting-edge sequencing technologies and innovative methods for chromosome visualization to elucidate the mechanisms of recurrent degeneration and loss of the pseudoautosomal region (PAR) in voles (genus Microtus). This research will draw on diverse research fields, including genomics, evolutionary biology, and cytogenetics. Dr. Trudy Mackay, William Neal Reynolds and Distinguished University Professor of Genetics, will act as the primary mentor for my scientific development. Dr. Mackay is a world-renowned for her work in evolutionary and quantitative genetics, and has an impressive record of successful students and postdocs as a testament to her commitment and enthusiasm for training young investigators. Dr. David Threadgill, Professor and head of the Department of Genetics at NCSU, will provide specific instruction in mouse functional genetics. Dr. Matthew Breen and Dr. Lisa McGraw, both at NCSU, will provide focused mentoring in cytogenetics and vole genetics, respectively. The remarkable breadth of faculty research interests and their overlap with the intellectual and experimental foci of the proposed training program make NCSU the optimal place for conducting the mentored phase of this research. The mammalian PAR promotes pairing, synapsis, and recombination between the heterogametic sex chromosomes at meiosis. These processes are integral to proper sex chromosome segregation. Failure to initiate pairing or recombination in the PAR can lead to spermatogenic failure, infertility, and sex chromosome aneuploidy, including Turner and Kleinfelter Syndromes in humans. Despite its important meiotic function, the PAR is structurally dynamic, rapidly evolving, and has even been completely lost in several exceptional mammalian species. Voles (genus Microtus) display particularly exciting trends in recent PAR evolution. Across the vole phylogeny, there is evidence for ¿3 parallel losses of X/Y chromosome pairing at meiosis, including multiple closely related species pairs with and without meiotic sex chromosome associations. I propose to study these recurrent evolutionary episodes to address 3 specific questions: 1. What structural and sequence-level changes precipitated the degeneration and loss of the PAR along these vole lineages? I propose cytogenetic assays and genome sequence comparisons between closely related vole species with and without meiotic X/Y pairing and recombination to answer this question. 2. How do unpaired, achiasmate sex chromosomes reliably segregate at meiosis? I propose cytological studies linking sex chromosome dynamics with the localization patterns of meiotic proteins to identify candidate achiasmate segregation genes. 3. Do candidate X/Y segregation genes identified in voles rescue sex chromosome segregation defects in organisms with obligate requirements for PAR pairing that harbor disruptive mutations across the region? I will carry out these functional tests using a mouse model with a high frequency of sex chromosome aneuploidy. The availability of multiple, independent episodes of PAR loss across the vole phylogeny presents a logical transition between a mentored phase focused on dissecting the basis of X/Y pairing loss in one species set, and an independent investigator phase that builds on this training to determine the mechanisms of PAR degradation and sex chromosome segregation in other vole species. The proposed research program will provide key insights into the mechanisms of PAR evolution and sex chromosome segregation at meiosis, with potential clinical consequences for understanding the genesis of sex chromosome aneuploidies in humans.

描述(由申请人提供)：我正在提议一个培训计划，为我在进化基因组学领域的独立研究生涯做准备。我在威斯康星大学麦迪逊分校遗传学实验室获得博士学位，是因为我在哺乳动物物种全球重组率差异的遗传和进化基础上所做的工作。然后，我在华盛顿大学基因组科学系完成了为期两年的博士后研究，在那里我获得了相当多的经验，并精通了大型基因组数据集的计算分析。通过拟议的培训计划，我将扩大我的实验技能集，包括基因组库构建、多样化的细胞遗传学方法，以及在哺乳动物模型系统中对候选基因的功能分析。我提议一个为期5年的研究计划，包括在北卡罗来纳州立大学(NCSU)进行为期2年的生物复杂性倡议有组织的指导和培训，然后是为期3年的独立研究阶段。拟议的培训计划将利用尖端测序技术和创新的染色体可视化方法来阐明田鼠(田鼠属)伪常染色体区域(PAR)反复退化和丢失的机制。这项研究将涉及不同的研究领域，包括基因组学、进化生物学和细胞遗传学。威廉·尼尔·雷诺兹博士和杰出的大学遗传学教授特鲁迪·麦凯博士将担任我科学发展的主要导师。麦凯博士在进化论和数量遗传学方面的工作享誉世界，她在成功的学生和博士后方面有着令人印象深刻的记录，这证明了她对培养年轻研究人员的承诺和热情。NCSU遗传学系主任兼教授David Threadgill博士将在小鼠功能遗传学方面提供具体指导。NCSU的Matthew Breen博士和Lisa McGraw博士将分别提供细胞遗传学和田鼠遗传学方面的重点指导。教师研究兴趣的显著广度及其与拟议培训计划的智力和实验重点的重叠，使NCSU成为进行本研究指导阶段的最佳地点。哺乳动物的PAR在减数分裂过程中促进异性配子染色体之间的配对、突触和重组。这些过程对于正确的性染色体分离是不可或缺的。未能在PAR中启动配对或重组可导致生精障碍、不育和性染色体非整倍体，包括人类的Turner和Kleinfelter综合征。尽管PAR具有重要的减数分裂功能，但它在结构上是动态的，进化迅速，甚至在几个特殊的哺乳动物物种中已经完全消失。田鼠(田鼠属)在最近的PAR进化中表现出特别令人兴奋的趋势。纵观田鼠的系统发育，有证据表明减数分裂时X/Y染色体配对的平行丢失，包括具有和不具有减数分裂性染色体关联的多个密切相关的物种对。我建议研究这些反复发生的进化事件，以解决三个具体问题：1.是什么结构和序列水平的变化导致了这些田鼠血统上PAR的退化和丢失？为了回答这个问题，我建议用细胞遗传学分析和基因组序列比较的方法，对有和没有减数分裂X/Y配对和重组的近缘种田鼠进行比较。2.未配对的、完全配对的性染色体如何在减数分裂时可靠分离？我建议进行细胞学研究，将性染色体动态与减数分裂蛋白的定位模式联系起来，以确定候选的成虫分离基因。3.在田鼠身上发现的候选X/Y分离基因是否可以挽救具有专有PAR配对要求的生物体中的性染色体分离缺陷，这些生物体在整个地区都存在破坏性突变？我将使用一个性染色体非整倍体频率很高的小鼠模型进行这些功能测试。在田鼠系统发育过程中出现多个独立的PAR缺失事件，呈现了一个逻辑上的转变，一个是专注于剖析一个物种集合中X/Y配对缺失基础的指导阶段，另一个是建立在这种训练基础上的独立研究阶段，以确定PAR降解和其他田鼠物种的性染色体分离的机制。这项研究计划将对PAR进化和减数分裂时性染色体分离的机制提供关键的见解，对理解人类性染色体非整倍体的起源具有潜在的临床意义。