DISSERTATION RESEARCH: Molecular and Morphological Perspectives on the Dynamics of a Post-glacial Contact Zone

论文研究：冰河后接触带动力学的分子和形态学视角

• 批准号: 0309377
• 负责人: Marjorie Matocq
• 金额: $ 1.1万
• 依托单位: Idaho State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0309377&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Molecular; Morphological; Perspectives

Hybrid zones provide excellent opportunities to study evolutionary processes. By elucidating mechanisms that shape hybrid zones, we can begin to understand the role of evolutionary factors such as selection, barriers to genetic exchange, and new adaptations. The dynamic glacial events of the late Pleistocene (130,000 - 10,000 years ago) are believed to have modified geographic distributions of many high latitude organisms and created contact zones. While many of the documented post-glacial contact zones are Eurasian, phylogeographic studies in North America are demonstrating post-glacial contact following the retreat of the ice sheets. Preliminary research on a post-glacial contact zone between the northern red-backed vole (Clethrionomys rutilus) and southern red-backed vole (Clethrionomys gapperi) in southeast Alaska documented unidirectional introgression of the mitochondrial genome of C. rutilus into populations of C. gapperi. The proposed work will use additional molecular markers and morphometric tools to explore fundamental evolutionary processes in this hybrid zone. The red-backed vole contact zone is an excellent model system because the phylogeographic histories of these taxa are well known. These species contact each other over 2000 km, providing an opportunity to study interspecific dynamics at multiple localities to test for the consistency of processes that may be shaping this contact zone. Using individuals from populations across three transects of the contact zone, the study will combine morphological data, sequences of the cytochrome b, Sry, MHY2 genes, and 12 microsatellite loci to address the following questions: What is the direction of introgression? Is introgression contemporary? What are the fates of the hybrids? Are the consequences of interspecific interactions the same across multiple transects of the contact zone?

混合区为研究进化过程提供了绝佳的机会。通过阐明形成混合区的机制，我们可以开始了解进化因素的作用，例如选择、遗传交换的障碍和新的适应。据信，晚更新世（130,000 - 10,000 年前）的动态冰川事件改变了许多高纬度生物的地理分布并形成了接触区。虽然许多记录在案的冰期后接触区是欧亚大陆，但北美的系统发育地理学研究表明，冰盖退缩后存在冰期后接触区。对阿拉斯加东南部北部红背田鼠 (Clethrionomys rut​​ilus) 和南部红背田鼠 (Clethrionomysgapperi) 之间冰期后接触区的初步研究记录了 C. rutilus 线粒体基因组单向渗入到 C.gapperi 种群中。 拟议的工作将使用额外的分子标记和形态测量工具来探索这个混合区域的基本进化过程。 红背田鼠接触区是一个很好的模型系统，因为这些类群的系统发育历史是众所周知的。这些物种相互接触的距离超过 2000 公里，为研究多个地点的种间动态提供了机会，以测试可能塑造该接触区的过程的一致性。该研究将利用来自接触区三个横断面的种群中的个体，结合形态学数据、细胞色素b、Sry、MHY2基因的序列和12个微卫星位点来解决以下问题：基因渗入的方向是什么？ 基因渗入是当代的吗？混血儿的命运又是怎样呢？ 在接触带的多个横断面上，种间相互作用的后果是否相同？