Evolutionary Ecology of sex-ratio variation in Tigriopus

虎鱼性别比例变异的进化生态学

• 批准号: RGPIN-2015-06224
• 负责人: Anholt, Bradley
• 金额: $ 2.33万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=614019
• 关键词: Evolutionary; Ecology; sex; ratio; variation

Understanding why sex ratio is usually equal and predicting when it should deviate from equality is one of the success stories of evolutionary biology. However, in diploid organisms there is very little variation for sex ratio so the supporting data is almost all observational. The small crustacean copepod Tigriopus californicus has heritable variation for sex ratio and extraordinarily wide phenotypic variation in sex ratio. It produces its first eggs three weeks after hatching, and females mate only once, which makes sequential clutches full sibs.  This makes it ideal to test sex ratio theory experimentally. This animal lives in the splash zone above the high tide line in small pools that frequently dry out. Populations are maintained by frequent dispersal. They are easily maintained in the laboratory and experimental breeding programs are easy to implement.  My research group has been able to  create selected lines that are reliably biased towards producing male or female biased clutches of offspring.  A Quantitative Trait Locus study showed that there are at least 6 loci on 5 (of 12) chromosomes that are significantly associated with clutch sex ratio. This research program seeks to accomplish the following. 1) Understand the unusual features of the Tigriopus sex-determination system. 2) Determine whether population subdivision maintains the wide variation in sex ratio seen in Tigriopus using both theoretical and experimental approaches.   3) Use experimental evolution to test the predictions of sex-ratio theory.  Studies of experimental evolution will be supplemented with high-throughput genomic methods to ascertain whether there are repeatable patterns in the genetic changes associated with evolutionary changes in the sex-ratio phenotype.

理解为什么性别比例通常是相等的并预测何时应该偏离平等是进化生物学的成功故事之一。然而，在二倍体生物中，性别比例的变化非常小，因此支持数据几乎都是观测数据。小型甲壳类桡足类Tigriopus californicus具有可遗传的性别比变异和极其广泛的性别比表型变异。它在孵化三周后产下第一批卵，雌性只交配一次，这使得连续的窝成为完整的同胞。  这使得通过实验检验性别比理论成为理想的选择。这种动物生活在高潮线以上的溅水区的小水池中，这些水池经常干涸。种群通过频繁的分散来维持。它们易于在实验室中维护，并且实验育种计划易于实施。  我的研究小组已经能够创建选定的品系，这些品系可靠地偏向于产生雄性或雌性偏向的后代。  一项数量性状基因座研究表明，5 条（12 条）染色体上至少有 6 个基因座与窝性别比显着相关。 该研究计划旨在实现以下目标。 1) 了解虎龙性别决定系统的不寻常特征。 2) 使用理论和实验方法确定种群细分是否维持虎鱼性别比例的广泛变化。   3）用实验进化来检验性别比理论的预测。  实验进化研究将辅以高通量基因组方法，以确定与性别比例表型进化变化相关的遗传变化是否存在可重复的模式。