Dissecting the Mechanisms of Host-Parasite Coevolution Mediating Reciprocal Local Adaptation CLUSTER: "Evolutionary Genetics of Three-Spined Stickleback - Parasite Interactions"

剖析宿主-寄生虫协同进化介导相互局部适应集群的机制：“三刺鱼-寄生虫相互作用的进化遗传学”

• 批准号: 224977492
• 负责人: Dr. Christophe Eizaguirre
• 金额: --
• 依托单位: School of Biological and Behavioural Sciences
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/224977492?language=en
• 关键词: Dissecting; Mechanisms; Host; Parasite; Coevolution

Host-parasite coevolution is known to be one of the adaptive driving forces of evolution. It is now accepted that hosts and their parasites are engaged in a never ending arms race which should select for the fittest hosts’ and the fittest parasites’ genotypes every generation anew. This arms race often ends in local adaptation of either one or both partners. Though crucial for the understanding of adaptive evolution, genetically resolved examples of local adaptation are rare. The major histocompatibility complex (MHC) with its key function in parasite resistance represents an ideal candidate to investigate parasite-mediated host local adaptation. In this project, we take advantage of the occurrence of the three-spined sticklebacks in replicated but genetically distinct lake/river ecotypes to investigate the potential local adaptation of MHC genes and its influence on the parasite genetic pools. Fish from those habitat types harbor different parasite species among which Gyrodactylus gasterostei - a common stickleback trematode parasite which varies genetically and consistently in intensity of infection between habitat types. Using a combination of field and lab experiments based on second generation of lab-bred three-spined stickleback hybrids of lake and river population, we aim to test for 1) host local adaptation of MHC genotypes to habitat-specific parasites. 2) parasite’s Darwinian fitness influenced by the host MHC genotypes. Thanks to the fish quantitative breeding design, in both cases, the reciprocal strength of selections will be quantified independently of the fish genetic background. Such work would represent the only example of genetically resolved host local adaptation and would demonstrate the role of host distribution in affecting parasite population genetic structure. And last, but not least, such a breeding scheme represents ideal system to test for immune related genes identified by Reusch, Bornberg-Bauer and Stoll in the field.

宿主-寄生虫的共同进化被认为是进化的适应性驱动力之一。现在人们普遍认为，宿主和寄生虫正在进行一场永无止境的军备竞赛，每一代人都应该重新选择最适合的宿主和最适合的寄生虫的基因类型。这场军备竞赛往往以一方或双方在当地适应而告终。虽然对理解适应性进化至关重要，但通过基因解决局部适应的例子并不多见。主要组织相容性复合体(MHC)在寄生虫抗性中起关键作用，是研究寄生虫介导的宿主局部适应的理想候选基因。在这个项目中，我们利用三刺刺鱼在复制但遗传上不同的湖泊/河流生态型中的出现来研究MHC基因潜在的局部适应及其对寄生虫基因库的影响。这些栖息地类型的鱼有不同的寄生虫种类，其中包括腹足吸虫，这是一种常见的刺背吸虫寄生虫，其感染强度在不同栖息地类型之间存在遗传差异和一致性。利用基于实验室培育的第二代湖泊和河流种群的三刺刺鱼的野外和实验室实验相结合的方法，我们的目标是测试1)宿主对栖息地特定寄生虫的MHC基因的局部适应。2)寄生虫的达尔文适合度受寄主MHC基因的影响。由于鱼的数量繁育设计，在这两种情况下，选择的相互强度将独立于鱼的遗传背景而被量化。这项工作将是基因解决的宿主局部适应的唯一例子，并将证明宿主分布在影响寄生虫种群遗传结构中的作用。最后，同样重要的是，这样的育种方案代表了一种理想的系统，可以在野外测试Reusch、Bornberg-Bauer和Stoll确定的免疫相关基因。