Doctoral Dissertation Improvement: Population genomics of a baboon hybrid zone in Zambia

杂交，被定义为遗传上不同种群之间的杂交，越来越多地被认为是植物和动物中常见的现象，对于理解物种形成过程是重要的。虽然大多数物种形成可能是由于遗传交换的物理障碍造成的，但这种分离并不总是绝对的，杂交的可能性一直存在。在灵长类动物中，大多数主要的分类学群体中都发现了正在进行的杂交，最近的研究越来越多地在包括人类在内的现存灵长类动物的基因组中检测到古代杂交的事件。然而，杂交的机制及其在塑造灵长类进化史中的作用仍未解决。这项由圣路易斯华盛顿大学博士生Kenneth Chiou在简·菲利普斯-康罗伊博士的指导下进行的研究，将杂交作为一种自然实验，以了解在赞比亚卡福国家公园内及其周围杂交的基达和灰脚查克玛狒狒的遗传变异的空间结构。像人类一样，狒狒生活在不同的环境中，有着悠久的生活史和复杂的社会组织，并且有着共同的祖先，这使它们成为了解人类遗传变异全球模式的理想模式。使用最新的DNA测序技术，来自核和线粒体基因组的数万个标记被分型，来自杂交区的个体。这些标记被用来更好地理解局部适应和社会组织差异在构建种内、种间和种间杂交遗传变异中的作用。这项研究为表征各种过程对遗传变异的影响提供了一个创新的框架。作为对野生灵长类杂交区的首批基因组研究之一，这项研究增加了我们对自然杂交的理解，并产生了第一个大片区域的主要狒狒接触区的遗传数据。DNA序列数据存放在公共数据库中，所有软件都是根据开放源码许可证免费提供的。通过在美国和国外创造合作和拓展的机会，该项目有助于促进科学素养和维护生物多样性。

Hybridization, defined as interbreeding between genetically distinct populations, is increasingly recognized as a common occurrence in plants and animals that is important for understanding the speciation process. While most speciation probably results from physical barriers to genetic interchange, this separation is not always absolute and the possibility of hybridization is ever-present. In primates, ongoing hybridization has been identified in most major taxonomic groups and recent studies are increasingly detecting episodes of ancient hybridization in the genomes of living primates, including humans. The mechanisms of hybridization and its role in shaping primate evolutionary histories, however, remain unresolved.This research by doctoral student Kenneth Chiou (Washington University in St. Louis), under the supervision of Dr. Jane Phillips-Conroy, uses hybridization as a 'natural experiment' for understanding the spatial structure of genetic variation in Kinda and gray-footed chacma baboons, which hybridize in and around Kafue National Park, Zambia. Like humans, baboons inhabit diverse environments, have long life histories and complex social organizations, and share a recent common ancestor, making them ideal models for understanding global patterns of genetic variation in humans. Using the latest DNA sequencing techniques, tens of thousands of markers from across the nuclear and mitochondrial genomes are typed from individuals across the hybrid zone. These markers are used to better understand the roles of local adaptation and of differences in social organization in structuring genetic variation within species, between species, and in interspecific hybrids.This study provides an innovative framework for characterizing the influences of various processes on genetic variation. As one of the first genomic studies of a wild primate hybrid zone, this study increases our understanding of natural hybridization and generates the first genetic data for large areas of a major baboon contact zone. DNA sequence data are deposited in public databases and all software is made freely available under open source licenses. By creating opportunities for collaboration and outreach in both the United States and abroad, this project helps promote scientific literacy and the maintenance of biodiversity.