Mechanisms of speciation in sympatry in polymorphic crater lake cichlid fish: the Neotropical Amphilophus citrinellus species complex

多态性火山口湖慈鲷鱼同域物种形成机制：新热带Amphilophus citrinellus物种复合体

• 批准号: 5363031
• 负责人: Professor Dr. Axel Meyer
• 金额: --
• 依托单位: Lehrstuhl für Zoologie/Evolutionsbiologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2002
• 资助国家: 德国
• 起止时间: 2001-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5363031?language=en
• 关键词: Mechanisms; speciation; sympatry; polymorphic; crater

Recently, both theoretical and empirical evidence for sympatric speciation suggested that some evolutionary conditions are conducive to speciation in sympatry. The Midas cichlid species complex (Amphilophus citrinellus) fits several of the key characteristics of these models - with strong assortative mating on the basis of a color polymorphism coupled with trophic and ecological differentiation based on a polymorphism in their pharyngeal jaws. This species complex is a young radiation in the process of speciation. We plan to use microsatellite markers and a segment of the mtDNA control region to study the population-genetics of polymorphic populations of the Midas cichlid species complex from three crater lakes and two large lakes in Nicaragua. All populations are known to be strongly genetically differentiated on the basis of geography. So far the available evidence suggests that genetic separation, even in fully sympatric conditions of the crater lakes, is more strongly based on color and we failed to find significant genetic structuring based on trophic differences and ecological niche separation between jaw morphs. Preliminary data therefore support the hypothesis that sexual selection contributes more strongly or earlier during the process of speciation than ecological separation. In this project we plan to increase the sampling and the ecological characterization of both morphs of Amphilophus citrinellus, and its closely related species, to investigate the rates of divergence (genetically and phenotypically - through morphometrics) and the mechanisms of repeated sympatric speciation in parallel ecological systems.

最近，同域物种形成的理论和经验证据都表明，某些进化条件有利于同域物种形成。米达斯慈鲷物种复合体（Amphilophus citrinellus）符合这些模型的几个关键特征-强烈的相互交配的基础上的颜色多态性，再加上营养和生态分化的基础上，在他们的咽颚的多态性。这种物种复合体是物种形成过程中的年轻辐射。我们计划使用微卫星标记和mtDNA控制区的一部分，研究人口遗传学的多态性人口的迈达斯慈鲷物种复杂的火山口湖和两个大湖在尼加拉瓜。已知所有种群在地理上都有很强的遗传差异。到目前为止，现有的证据表明，遗传分离，即使在完全同域条件下的火山口湖泊，是更强烈的颜色，我们未能找到显着的遗传结构的基础上的营养差异和生态位分离的颌骨形态。因此，初步的数据支持的假设，性选择的贡献更强烈或更早的物种形成过程中比生态分离。在这个项目中，我们计划增加两种形态的双冠菊及其密切相关的物种的采样和生态特征，调查的分歧率（遗传和表型-通过形态测量学）和机制的重复同域物种形成在平行的生态系统。