DISSERTATION RESEARCH: The Genomic Nature of Adaptation in Anolis lizards

地球上的大多数生物多样性被认为是适应性辐射的结果，这是一种进化现象，许多新物种通过殖民化和适应新环境而迅速形成。在过去的50年里，许多研究人员的工作导致了对与适应性辐射相关的大范围进化模式的新兴理解。尽管取得了这些进展，但我们对适应性辐射期间发生的遗传过程知之甚少。例如，目前尚不清楚新突变在一个环境中单独受到青睐的频率，以及在不同栖息地中对多个物种有益的频率。这一建议利用适应性辐射最具代表性的例子之一——西印度群岛的蜥蜴来解决我们知识上的这一空白。这项研究将集中在两种栖息在树干上的Anolis物种。一种生活在炎热干燥的环境中，另一种生活在潮湿凉爽的森林中。在多米尼加共和国的一小块地区，这些不同的栖息地彼此紧挨着。在这里，两个物种杂交并形成杂交后代。这些独特的环境提供了一个机会来确定哪些基因变异与适应两种不同的环境有关，哪些变异对两个物种都有益。为了解决蜥蜴适应的基因组本质，共同研究人员将使用下一代测序技术收集每个物种个体以及杂交物种的转录组数据。从该测序中获得的基因型将用于进行基因组突变分析，以确定杂交品种中代表性过高和代表性不足的亲本等位基因。基因组突变分析的结果将与种群基因组分析相结合，以确定全球和局部适应的频率，并提供与适应性辐射相关的微进化过程的第一个见解。

Most of the biological diversity on Earth is thought to result from adaptive radiation, an evolutionary phenomenon where many new species are rapidly formed through colonization of and adaptation to new environments. The work of many researchers over the last fifty years has resulted in an emerging understanding of the broad-scale evolutionary patterns associated with adaptive radiation. Despite these advances, we have little understanding of the genetic processes that take place during adaptive radiation. For instance, it is not known how often new mutations are uniquely favored in one environment alone versus being beneficial to multiple species living in different habitats. This proposal addresses this gap in our knowledge using one of the most iconic examples of adaptive radiation, Anolis lizards from the West Indies. This research will focus on two Anolis species that reside on tree trunks?one living in a hot, dry environment, the other in a moist, cool forest. In a small area of the Dominican Republic, these different habitats are immediately adjacent to one another. Here, the two species interbreed and form hybrid offspring. These unique circumstances provide an opportunity to identify what gene variants are associated with adaptation to the two distinct environments and what variants are beneficial to both species.To address the genomic nature of adaptation in Anolis lizards, the co-investigators will use next-generation sequencing technologies to collect transcriptome data from individuals of each species as well as hybrids. The genotypes derived from this sequencing will be used to perform genomic cline analyses, which identify parental alleles that are over- and underrepresented among hybrids. The results of genomic cline analyses will be combined with population genomic analyses to identify the frequency of global and local adaptations and provide a first insight into the microevolutionary processes associated with adaptive radiation.