Allopolyploidization, Niche Evolution, and Systematics of Central African Night Frogs

大多数脊椎动物物种是二倍体：它们有两套染色体，分别来自父母。在一些物种中，每一组都有重复，导致物种成为多倍体（即，它有两套以上的染色体）。当两个物种杂交，从而产生一个新的多倍体物种，包含两套染色体从每个“父母”物种时，这可能发生。新形成的物种可能与其亲本物种竞争，因此可能进化到占据新的环境。多倍体物种与其二倍体亲本之间的竞争在植物中进行了研究，但在动物中却没有。该项目将重点关注西非和中非森林中两个密切相关的蛙类，它们已知表现出多倍性：夜蛙（Astylosternus属）和毛蛙（Trichobatrachus属）。该项目将从这两个群体的所有物种中收集数千个基因的新数据。研究人员将分析这些数据，以建立这些青蛙之间的关系，并测试有关多倍体物种如何与亲本物种竞争的假设，并可能被驱使创造新的生态位，即使在相对恶劣的环境中。这些结果将为多倍体物种如何以及为什么栖息在极端环境中提供新的理解。更好地记录分布和环境要求也将为六个被认为受到栖息地丧失威胁的目标物种的保护工作提供信息。本计画将训练本科生并发展线上学习模组，以帮助本科生了解多倍体物种的科学。研究人员将为美国和喀麦隆的科学家举办一个培训研讨会，为他们提供使用新工具分析多倍体物种分布和进化的实践培训。该项目将促进我们对多倍体物种产生过程和相关生态位进化的理解。它还将增加我们对这些过程如何影响热带生态系统中新脊椎动物物种形成的理解。该项目将开发新的方法来构建祖先国家重建的基本生态位的时间校准的多倍体系统发育网络。这些方法将广泛适用于多倍体植物和动物。重点属Astylosternus和Trichobatrachus分布在中非的森林类型和海拔梯度。因此，它们代表了一个独特的脊椎动物系统，用于研究影响多倍体物种通过杂交和随后的生态位进化的地理，气候和时间因素。综合系统发育关系、物种分布、可用的广告电话和CT扫描新收集的解剖数据，也将有助于对这些鲜为人知的青蛙进行彻底的分类修订，包括发现未描述的物种。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Most vertebrate species are diploid: they have two sets of chromosomes, one from each parent. In some species, there is a duplication of each set leading the species to become polyploid (i.e., it has more than two sets of chromosomes). This can happen when two species hybridize and thus create a new polyploid species that contains both sets of chromosomes from each “parent” species. The newly formed species may be in competition with its parental species and may therefore evolve to occupy new environments. Competition between polyploid species and their diploid parents has been studied in plants but not in animals. This project will focus on two closely related groups of frogs from forests in West and Central Africa that are known to exhibit polyploidy: Night Frogs (genus Astylosternus) and Hairy Frogs (genus Trichobatrachus). The project will collect new data for thousands of genes from all of the species in these two groups. The researchers will analyze these data to establish the relationships among these frogs and to test hypotheses about how polyploid species compete with parental species and are potentially driven to create new ecological niches, even in relatively inhospitable environments. The results will provide new understanding about how and why polyploid species come to inhabit extreme environments. Better documentation of distributional and environmental requirements will also inform conservation efforts for six of the targeted species that are considered threatened by habitat loss. This project will train undergraduate students and develop on-line learning modules to help undergraduates understand the science of polyploid species. The researchers will lead a training workshop for scientists in the U.S. and Cameroon that will provide hands-on training for use of new tools to analyze the distribution and evolution of polyploid species.This project will advance our understanding of the processes generating polyploid species and the associated evolution of ecological niches. It will also add to our understanding of how these processes impact the formation of new vertebrate species in tropical ecosystems. The project will develop new methods to construct ancestral state reconstructions of fundamental niches on time-calibrated polyploid phylogenetic networks. These methods will be broadly applicable across polyploid plants and animals. The focal genera Astylosternus and Trichobatrachus are distributed across forest types and elevational gradients in Central Africa. They thus represent a unique vertebrate system for studying the geographic, climatic, and temporal factors that influence the creation of polyploid species through hybridization and subsequent niche evolution. Synthesis of phylogenetic relationships, species distributions, available advertisement calls, and newly collected anatomical data from CT-scanning will also facilitate a thorough taxonomic revision of these poorly known frogs, including the discovery of undescribed species.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.