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平等的，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察数据。小型桡足类的性比具有可遗传的变异和极宽的表型变异。它在孵化后三周产下第一个蛋，雌性只交配一次，这使得连续的窝都是同胞。 这使得通过实验来检验性别比例理论成为一种理想的方法。这种动物生活在高潮线以上的飞溅区，在经常干涸的小水池里。种群是通过频繁的扩散来维持的。它们很容易在实验室中维护，实验性育种计划也很容易实施。 我的研究小组已经能够创造出可靠的偏向于产生雄性或雌性偏向的后代的选择线。 数量性状基因座研究表明，在12条染色体中的5条上至少有6个基因座与窝卵性比显著相关。 该研究计划旨在实现以下目标。1)了解虎首虎性别决定系统的不寻常特征。2)确定人口细分是否保持广泛的变化，在Tigriopus使用理论和实验方法的性别比例。 3)用实验进化来检验性别比例理论的预测。 实验进化的研究将补充高通量基因组学方法，以确定是否有可重复的模式，在遗传变化与性别比例表型的进化变化。