The genetics of reproductive isolation and speciation in north Atlantic sea urchins

北大西洋海胆生殖隔离和物种形成的遗传学

• 批准号: RGPIN-2014-05214
• 负责人: Addison, Jason
• 金额: $ 1.75万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=631748
• 关键词: genetics; reproductive; isolation; speciation; north

The origin of new species remains the central and most elusive question in evolutionary biology. In marine environments, the problem of genetic divergence and speciation is especially complex, because the barriers to genetic exchange that are generally essential for allowing divergence to occur are far more subtle than in terrestrial systems. Both divergent selection along ecological boundaries, and the evolution of gamete incompatibilities to prevent hybridization (i.e., reinforcement) are expected to play key roles in the process of speciation in the sea, but exactly how these forces counteract the homogenizing effects of gene flow has long been debated. My research uses exciting advances in next generation sequencing techniques to investigate species divergence at the level of the genome. I focus on a contact zone between two species of broadcast spawning sea urchins in the northwest Atlantic, where populations overlap and hybridization frequently occurs. Hybrid zones are ideal “natural laboratories” for examining the role of selection in the process of speciation, because the fate of individuals with mixed ancestry can be traced as they move and from one ecological setting to another. Using both laboratory and field studies my students and I (i) will determine how many different genes are involved in the evolution of reproductive isolation across the hybrid zone, (ii) assess the role of adaptation to different habitats as a mechanism of reproductive isolation, and (iii) better understand the role of reinforcement at gamete recognition molecules that may have evolved to prevent hybridization from occurring. The experiments outlined in this proposal will extend our knowledge of the factors driving reproductive isolation at the population level, and contribute to a general understanding of the relative importance that the opposing forces of diversifying selection, gene flow and genetic drift play in the process of speciation.

新物种的起源仍然是进化生物学中的核心和最弹性的问题。在海洋环境中，遗传差异和规格的问题尤其复杂，因为遗传交换的障碍通常对于允许发生分歧的发生至关重要的是比陆地系统更微妙。期望沿生态边界的不同选择以及配子不兼容的防止杂交（即增强）的演变在海中的规范过程中起关键作用，但是这些力量如何抵消基因流的均质化作用，这是长期以来一直在争论的。我的研究使用了下一代测序技术中令人兴奋的进步来研究基因组水平的物种差异。我专注于在西北大西洋的两种广播产卵海胆之间的接触区，那里的种群重叠和杂交经常发生。混合区是理想的“自然实验室”，用于检查选择在规范过程中的作用，因为当他们移动并从一个生态环境到另一个生态环境时，具有混合血统的个体的命运可以追溯到。使用实验室和现场研究，我和我的学生（i）将确定在整个杂种区的生殖隔离演变中涉及多少不同的基因，（ii）评估对不同栖息地的适应性作为生殖隔离的机制，（iii）更好地理解强化在游戏中识别分子的作用，以免发生杂种。该提案中概述的实验将扩展我们对在人群水平上推动生殖隔离的因素的了解，并有助于对相对重要性的一般理解，即在规范过程中相对的多元化选择，基因流和遗传漂移的影响。