Dissertation Research: Genetics of Incipient Speciation in Two Species of Salticids

9520668麦迪逊，人们对导致地球上生命多样性的力量知之甚少。这项研究将比较两种跳蛛的遗传学，试图了解推动物种形成的过程。这两个物种隔离在亚利桑那州东南部的山脉上，似乎正在以非常快的速度进化。它们的栖息地在10,000到14,000年前的山脉之间是连续的。在这短短的一段时间里，一个物种的雄性出现了相当大的分化。另一个密切相关的物种也表现出一些分歧，但没有达到如此惊人的程度。将对线粒体和核基因进行检查，以重建促进形态分化的遗传力。基因数据将被用来测试过去十年发展的新理论。其中之一，聚合论，试图通过检查一个物种的基因谱系来重建该物种过去的遗传结构。线粒体DNA的谱系曾被用来尝试推断人类的历史，但我们对线粒体总体上是如何进化的知之甚少。这项研究将增加我们对线粒体如何进化的知识，这可能会影响我们用这个分子解释未来遗传数据的方式。这项研究提供了一个独特的机会，在物种形成仍在发生的时候对其进行研究。亚利桑那州东南部的山脉是由于气候变化而彼此支离破碎的栖息地。它们可能会提供一个模型，从而更好地理解种群过去是如何应对范围分裂的。这样的理解将有助于制定保护战略，以应对由于人类干扰而造成的广泛的栖息地碎片化。

9520668 MADDISON The forces that have lead to the great diversity of life on earth are poorly understood. This study will compare the genetics of two species of jumping spiders in an attempt to understand the processes driving speciation. These two species, isolated on the mountain ranges in southeast Arizona, appear to be evolving at a very rapid rate. Their habitat was continuous between the mountain ranges as recently as 10,000 to 14,000 years ago. In this short period, males of one species have diverged considerably. Another closely related species also shows some divergence, but not nearly to such a striking degree. Mitochondrial and nuclear genes will be examined in order to reconstruct the genetic forces that have promoted morphological divergence. The genetic data will be used to test new theories developed in the past ten years. one of these, coalescent theory, attempts to reconstruct the past genetic structure of a species by examining a gene genealogy of that species. The genealogy of mitochondrial DNA has been used in attempts to infer the history of humans, but we know little about how mitochondria evolve in general. This study will add to our knowledge of how mitochondria evolve, which may influence how we interpret future genetic data with this molecule. This study allows a unique opportunity to examine speciation while it is still occurring. The mountain ranges in southeast Arizona are habitats that have become fragmented from each other due to climatic changes. They may provide a model that will lead to better understanding of how populations have responded to range fragmentation in the past. Such understanding will be useful in developing conservation strategies to deal with widespread habitat fragmentation due to human disturbance.