Evolution of High Latitude Birds

高纬度物种的进化与历史和当代环境变化有关。了解影响物种分布的历史过程的一种方法是通过使用分子标记。这些标记保留了历史事件以及当代进程的信息。北方北美洲包含了几个地区的次级接触人群之间的不同更新世避难所，被隔离了数千年。我目前的研究计划使用比较的方法来调查人口遗传结构。通过了解过去的气候变化和景观特征如何塑造当代人口，我们可以更好地了解他们的人口动态和集合种群的功能，并预测他们将如何应对未来的气候变化。此外，我们可以通过关注密切相关的同域物种来进一步了解生态多样化。 我的长期目标集中在景观特征和人口水平的过程和人口连接模式的历史范围变化的作用。我的研究揭示了一些具有相似生活史模式和栖息地要求的共同分布物种的对比遗传模式。其中一些模式与已知的物理障碍相对应，但其他模式则不符合，需要进一步研究以确定扩散障碍。作为我的研究的直接结果，我现在更好地理解了我所研究物种的冰后期殖民模式。我的研究计划的短期目标是研究：1）微观和宏观地理种群结构的物种与混合迁移策略，和2）内和种间接触区，以检查微观地理景观遗传学。短期项目的结合也使我们能够研究物种形成过程。例如，迁徙行为对种内基因流动的影响是什么，或者更具体地说，定居种群是否比同一物种的迁徙种群具有更高的种群结构水平？ 在过去的几年里，遗传分析的重大进展使研究人员能够回答甚至在十年前都不可能回答的问题。GIS技术和贝叶斯分析现在允许我使用古气候数据创建单个物种的历史范围图，并将其与我们的遗传数据进行比较。将更新、更强大的分析与传统标记和更多物种相结合，将使我们能够更好地了解进化过程。使用遗传工具，我将确定地理变异是否是限制基因流动或其他生态因素的结果。通过采用线粒体（mtDNA）和核（微卫星和单核苷酸多态性（SNP））位点的组合，我将能够获得更完整和准确的范围内的基因流和精细规模的群体遗传结构的图片。 通过研究北美西部物种（如紫雀）的精细尺度差异，并添加混合迁移策略物种的数据，我们将更好地了解基因流如何因行为和生态差异而发生。此外，通过比较来自不同类别的高度可变标记和占据相似地理区域的不同物种的数据，我们可以评估在变异模式和种群结构上是否存在共同的遗传特征。

The evolution of high latitude species is linked to both historical and contemporary environmental changes. One way to understand the historical processes influencing the species’ distribution is through the use of molecular markers. These markers retain information on historical events in addition to contemporary processes. Northern North America contains several areas of secondary contact between populations from different Pleistocene refugia that were isolated for thousands of years. My current research program uses a comparative approach to investigate population genetic structure. By understanding how past climate changes and landscape features have shaped contemporary populations, we can better understand their population dynamics, and metapopulation functioning and perhaps predict how they will respond to future climate change. In addition, we can gain further insights into ecological diversification by focusing on closely related sympatric species. My long term goals focus on the role of landscape features and historical range shifts on population level processes and patterns of population connectivity. My research has revealed contrasting genetic patterns in some co-distributed species with similar life history patterns and habitat requirements. Some of the patterns correspond to known physical barriers, but others do not and warrant further study to determine the barriers to dispersal. The patterns of postglacial colonization for my study species are now better understood as a direct result of my research. The short term goals of my research program are to study: 1) micro- and macro-geographic population structure in species with mixed migration strategies, and 2) intra- and inter-specific contact zones to examine microgeographic landscape genetics. The combination of short term projects also allows us to study the speciation process. For example, what is the influence of migratory behaviour on intraspecific gene flow or more specifically do resident populations have higher levels of population structure than migratory populations of the same species? In the last few years, major advances in genetic analyses have occurred allowing researchers to answer questions that were not possible even a decade ago. GIS technologies and Bayesian analyses now allow me to create historical range maps for individual species using paleoclimate data and compare these to our genetic data. Combining the newer and more powerful analyses with traditional markers and a larger number of species will allow us to better understand evolutionary processes. Using genetic tools, I will determine if geographic variation is the result of restricted gene flow or other ecological factors. By employing a combination of mitochondrial (mtDNA) and nuclear (microsatellite and single nucleotide polymorphisms (SNPs)) loci, I will be able to obtain a more complete and accurate picture of rangewide gene flow and fine scale population genetic structure. By examining fine scale differences in western North America species, such as purple finch, and adding data on species with mixed migration strategies, we will gain a better understanding of how gene flow is occurring as a result of behavioural and ecological differences. Furthermore by comparing data from different classes of highly variable markers and the different species occupying similar geographic areas, we can assess whether or not there is a common genetic signature on the patterns of variation and population structure.