The Genetic Consequences of Long Generation Times

9727161这项研究计划使用dna序列变异分析来量化来自三个大陆地区的淡水和陆地龟的种群分化水平：美国中部、亚马逊盆地西部和北部以及澳大利亚东部。在这些地区中的每一个地区，在过去的15,000年里都发生了严重的气候变化，这些变化对包括海龟在内的所有动植物的过去和现在的分布产生了影响。例如，大约17,000年前，北达科他州和明尼苏达州的大部分地区都处于冰川之下，而今天，这些地区完全居住着从温暖地区向北迁徙的物种。来自至少两个基因的DNA序列数据将被用来量化这些冰川后迁徙模式的程度，重点放在海龟上，因为它们的世代时间很长，应该显示这些过去事件对其当前种群的最大影响。更广泛地说，这些数据将提供关于如何使用来自长寿物种的分子遗传数据来了解迁徙水平、种群波动和种群稳定的信息。这些数据经常被用于从保护和管理到基础生态学和进化的学科，它们取决于这样一个假设，即过去的气候波动对当前人口的影响可以忽略不计。这些数据将告诉我们，这些假设是否有效，或者是否需要修改。

Shaffer 9727161 This research program uses the analysis of DNA sequence variation to quantify levels of population differentiation in freshwater and terrestrial turtles from three continental regions: the central United States, the western and northern Amazon basin, and eastern Australia. In each of these regions, there have been severe climate changes during the past 15,000 years, and these changes have had impacts on the past and current distribution of all plants and animals, including turtles. For example, about 17,000 years ago most of North Dakota and Minnesota were under glacial ice, whereas today they are fully inhabited by species that have migrated north from warmer areas. DNA sequence data from at least two genes will be used to quantify the extent of these post-glacial migration patterns, focussing on turtles because they have very long generation times, and should show the maximal impacts of these past events in their current populations. More generally, these data will provide information on how one can use molecular genetic data from long-lived species to understand levels of migration, population fluctuations, and population stability. Such data are frequently utilized in disciplines ranging from conservation and managment to basic ecology and evolution, and they hinge on the assumption that past climatic fluctuations have has a negligable impact on current populations. These data will inform us on whether such assumptions are valid, or are in need of revision.