Molecular phylogeny and speciation in a regional fauna

我的研究计划的中心目标是了解生物多样性在多个时空尺度上的起源和持续-从特定遗传位点的等位基因变异到生物地理尺度上的物种组合，以及跨越几代到数百万年的分歧。我的研究计划的长期主题是：(1)记录物种内部和物种之间进化分歧的模式，(2)检验关于这种变异的起源和持久性以及自然选择、杂交和变异等过程的相关性的假设，以及(3)将这些知识应用于生物多样性的保护。我研究北美西北部和北极的淡水和海洋鱼类，并将生态学和遗传学的方法整合在一起，以解决有机体和进化生物学中的这些核心问题，这些问题也具有重要的保护应用。我的研究提出了这样的问题：在一个进化分支中，物种之间的相互关系是什么？什么样的生物地理过程（例如，构造、海平面变化、气候变化）塑造了现存的多样性？当物种接触时，它们会杂交吗？如果是，杂交的频率和命运能告诉我们什么关于推动物种形成的地理、生态和遗传过程的信息？哪些生境特征影响同种种群间适应性和中性变异的程度和模式？本提案的关键主题是研究接触的物种，以测试有关全基因组杂交程度和生殖隔离的遗传基础的假设。我利用了两种Salvelinus， S. alpinus （Arctic char）和S. malma （Dolly Varden）在阿拉斯加西部的多个接触区域。我将在我们详细的核DNA微卫星分析的基础上，通过使用基因组测序方法，更好地确定在基因流动中区分这些物种的基因组的范围和特定区域，展示这些物种之间的接触和杂交。这项工作还将通过利用这两个物种的多个异域和同域种群的发生来探索生活史特征位移的假设，这些种群表达了淡水居民和溯河（海洋）生活史的全部范围。我的研究的重要性和新颖性包括：(1)理解进化中的一个基本未知（生物多样性的起源和持续），(2)为加拿大的生物多样性研究提供急需的培训，(3)说明栖息地和生物多样性持续之间的密切联系，这对保护评估和行动至关重要。（iv）强调(i)-(iii)在加拿大的北部地区，这些地区的研究相对不足，环境变化的风险也在增加。

The central goal of my research program is to understand the origins and persistence of biodiversity at multiple spatial and temporal scales - from allelic variation at specific genetic loci to the assemblage of species at a biogeographic scale, and divergences spanning a few generations to millions of years. The long-term themes of my research program are to: (i) document the patterns of evolutionary divergence within and among species, (ii) test hypotheses concerning the origins and persistence of this variation and the relevance of processes such natural selection, hybridization, and vicariance, and (iii) to apply this knowledge to the conservation of biodiversity. I study freshwater and marine fishes in northwestern North America and the Arctic and integrate methods in ecology and genetics to address these central inquiries in organismal and evolutionary biology that also have important conservation applications. My research poses questions such as: what are the interrelationships amongst species within a clade and what biogeographic processes (e.g., tectonics, sea level changes, climate change) have shaped extant diversity? When species come into contact, do they hybridize and if so, what can the frequency and fate of hybrids tell us about the geographic, ecological and genetic processes driving speciation? What habitat features influence the extent and patterns of adaptive and neutral variation among conspecific populations? The key theme of this proposal examines species that come into contact to test hypotheses concerning the genome-wide extent of hybridization and the genetic basis of reproductive isolation. I exploit the occurrence of multiple areas of contact between two species of Salvelinus, S. alpinus (Arctic char) and S. malma (Dolly Varden) in western Alaska. I will build on our detailed nuclear DNA microsatellite analyses demonstrating contact and hybridization between these species by using genomic sequencing approaches to better pinpoint the extent and specific regions of the genome that distinguish these species in the face of gene flow. This work will also explore the hypothesis of life history character displacement by exploiting the occurrence of multiple allopatric and sympatric populations of both species which express the full range of freshwater resident and anadromous (searun) life histories. The significance and novelty of my research includes:(1) understanding a fundamental unknown in evolution (the origins and persistence of biodiversity),(ii) providing much needed training in biodiversity research in Canada, (iii) illustrating the intimate connection between habitat and biodiversity persistence critical for conservation assessment and action, and (iv) providing some emphasis for (i)-(iii) in northern areas which are relatively understudied and at increasing risk in Canada from environmental change.