CAREER: Evolution of allosomes and dosage compensation in terrestrial isopods

职业：陆地等足动物异体的进化和剂量补偿

• 批准号: 1453298
• 负责人: Christopher Chandler
• 金额: $ 64.13万
• 依托单位: SUNY College at Oswego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2021-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1453298&HistoricalAwards=false
• 关键词: CAREER; Evolution; allosomes; dosage; compensation; CAREER; Evolution; allosomes; dosage; compensation

Allosomes are chromosomes that determine sex, like the X and Y chromosomes in mammals, and they play crucial roles in the evolutionary biology of species. They have evolved independently in a wide array of species, and while these chromosomes in different groups share many similarities, they also exhibit important differences. Explaining these differences, however, remains difficult. While a strong body of theoretical work makes several important predictions regarding the evolution of allosomes, conclusively testing those predictions has been difficult because most prior research has focused on a small subset of model organisms. This project will address this problem by examining allosomes in terrestrial isopod crustaceans, which include woodlice and pillbugs. Terrestrial isopods are an ideal group for these questions because they exhibit considerable variation in sex-determining mechanisms, but, surprisingly, their genomes have received little attention. The proposed experiments are designed to help explain why these chromosomes are so unique, and how they contribute to vital biological processes. Importantly, this project will also promote diversity in science and create hands-on educational opportunities for students, especially engaging those from under-served groups. First, a project-based genomics course will be developed, and course materials made publicly available. Second, an international summer program will be established that provides undergraduates at SUNY Oswego with opportunities to conduct research abroad. Finally, this work will generate interest in research on campus by allowing incoming freshmen participating in an existing science and math summer 'bridge' camp to take part in interdisciplinary laboratory activities.This project will address key questions on the evolution of allosomes in three species of terrestrial isopod crustaceans (Trachelipus rathkei, Porcellio laevis, and Armadillidium vulgare). This research will (i) identify where changes in sex-determining chromosomes have occurred on the isopod evolutionary tree; (ii) test whether genes on these chromosomes are affected more strongly than autosomal genes by natural selection and genetic drift; and (iii) test whether these species exhibit dosage compensation. A comparative approach using whole genome sequencing and gene annotation via RNA sequencing will be used to address the first two aims. Fluorescent in-situ hybridization (FISH) will also be used to determine homology of allosomes among species. The sex of terrestrial isopods can be experimentally manipulated through surgical ablation or implantation of androgenic glands, which offers a unique opportunity to accurately test for dosage compensation using RNA sequencing in manipulated and unmanipulated individuals of the same and opposite sex. By studying a unique taxonomic group, this research will help examine the generality of patterns suggested by earlier work on allosomes, providing significant insights into these influential components of so many organisms' genomes, including those of humans.

同种体是确定性别的染色体，例如哺乳动物中的X和Y染色体，它们在物种的进化生物学中起着至关重要的作用。它们已经在各种各样的物种中独立发展，尽管这些不同群体中的这些染色体具有许多相似之处，但它们也表现出重要的差异。但是，解释这些差异仍然很困难。虽然强大的理论工作对同种异体的演变做出了一些重要的预测，但最终测试这些预测是困难的，因为大多数先前的研究都集中在一小部分模型生物体上。该项目将通过检查陆地等异形甲壳类动物中的同种异体来解决这个问题，其中包括木质和药丸。陆地等类动物是这些问题的理想群体，因为它们在性别确定的机制上表现出很大的差异，但是令人惊讶的是，它们的基因组很少受到关注。提出的实验旨在帮助解释为什么这些染色体如此独特，以及它们如何促进重要的生物学过程。重要的是，该项目还将促进科学方面的多样性，并为学生创造动手的教育机会，尤其是与服务不足的团体相关的人。首先，将开发基于项目的基因组学课程，并公开提供课程材料。其次，将建立一项国际夏季计划，该计划在SUNY OSWEGO提供本科生提供在国外进行研究的机会。最后，这项工作将通过允许参加现有的科学和数学夏季“桥”营地的新生参加跨学科实验室活动来引起人们对校园的研究的兴趣。该项目将解决有关三种恐怖症的异源性甲壳虫（Tracheipus ratheipus rathekei，porcellio laevis，porcellio laevis laevis and Armadillid）的关键问题。 这项研究将（i）确定在等异形物进化树上发生性别确定的染色体的变化； （ii）通过自然选择和遗传漂移测试这些染色体上的基因是否比常染色体基因更强烈； （iii）测试这些物种是否表现出剂量补偿。 使用整个基因组测序和通过RNA测序的基因注释的比较方法将用于解决前两个目标。荧光原位杂交（FISH）也将用于确定物种之间同种异体的同源性。可以通过外科手术消融或植入雄激素的性能来在实验上操纵陆地等异形体的性别，该雄激素腺提供了一个独特的机会，可以使用RNA测序在操纵和无操纵的同性和异性的人中使用RNA测序来准确测试剂量补偿。 通过研究一个独特的分类群体，这项研究将有助于研究早期作品对同种异体的研究所暗示的模式的普遍性，从而对许多生物体的基因组（包括人类的基因组）提供了这些有影响力的成分的重要见解。