What are the fitness and evolutionary consequences of the Y chromosome?

Y 染色体的适应性和进化后果是什么？

• 批准号: RGPIN-2019-05780
• 负责人: Campbell, Lesley
• 金额: $ 2.4万
• 依托单位: Ryerson University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738510
• 关键词: What; fitness; evolutionary; consequences; chromosome

Adaptive explanations of the existence of male (Y) chromosomes have been coupled to increased individual fitness with reduced inbreeding and/or stronger sexual selection. Because the outcome of the two processes is increased fitness, it has, thus far, proved difficult to discriminate among them empirically. Experimental evidence to test the relative importance of Y chromosomes in these two important evolutionary processes is rare (if not absent, in a recent literature search) because it is also difficult to find dioecious organisms that can produce male phenotypes and gametes without also possessing the Y chromosome. Cannabis sativa is a dioecious plant with sex determined by an XY system; however, sex expression in this species is sensitive to environmental context. Thus, sex chromosomes and sex expression in cannabis can be decoupled: 1) plants can possess XY chromosome complements but produce either male or female flowers, or 2) they can possess XX chromosome complements but produce either male or female flowers. This plant provides an excellent platform to test basic hypotheses about the role of the Y chromosome in sexual differentiation and expression, sexual selection and inbreeding avoidance. The long-term objective of my research program is to discover principles that drive evolution as a consequence of demography, especially mating processes. We are in a unique position to test basic questions about chromosome complement and mating using a plant with flexible sex expression. Insights gleaned from this plant are transferrable to other dioecious plants (including Asparagus, Rumex, and hops). My research program will study the reproductive biology of cannabis by exploring: how genetic and environmental factors influence a) sex-specific heritability of quantitative traits, and b) shifts in sex expression; the consequences of flexible sex expression for: a) life history and fecundity, and b) the genetic composition of gametes and embryos; and the relative importance of Y chromosomes in reducing inbreeding or increasing sexual selection.This research program will allow us to finally separate the process of sex from sex chromosomes while still maintaining a dioecious system, and allow us to assess the role of the Y chromosome in mating and sexual selection. Furthermore, this research will train students in a diversity of skillsets, including ecological and population genetics, and protein biochemistry.

男性（Y）染色体的存在的适应性解释已经耦合到减少近亲繁殖和/或更强的性选择增加个人健身。由于这两个过程的结果是增加健身，它已被证明，到目前为止，很难区分它们之间的经验。测试Y染色体在这两个重要进化过程中的相对重要性的实验证据是罕见的（如果不是不存在的话，在最近的文献检索中），因为它也很难找到雌雄异株的生物体，可以产生雄性表型和配子，而不拥有Y染色体。大麻是一种雌雄异株的植物，其性别由XY系统决定;然而，该物种的性别表达对环境背景敏感。因此，大麻中的性染色体和性别表达可以解耦：1）植物可以具有XY染色体互补体，但产生雄花或雌花，或者2）它们可以具有XX染色体互补体，但产生雄花或雌花。这种植物提供了一个很好的平台来测试Y染色体在性分化和表达，性选择和避免近亲繁殖中的作用的基本假设。我的研究计划的长期目标是发现作为人口统计学结果的驱动进化的原则，特别是交配过程。我们处于一个独特的位置，可以使用具有灵活性别表达的植物来测试有关染色体互补和交配的基本问题。从这种植物中获得的见解可以转移到其他雌雄异株植物（包括芦笋，酸模和啤酒花）。我的研究计划将通过探索研究大麻的生殖生物学：遗传和环境因素如何影响a）数量性状的性别特异性遗传力，以及B）性别表达的变化;灵活的性别表达的后果：a）生活史和繁殖力，以及B）配子和胚胎的遗传组成;以及Y染色体在减少近亲繁殖或增加性选择方面的相对重要性。这项研究计划将使我们能够最终将性过程与性染色体分离，同时仍然保持雌雄异株系统，让我们能够评估Y染色体在交配和性选择中的作用。此外，这项研究将培养学生的各种技能，包括生态和种群遗传学，以及蛋白质生物化学。