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

杂交，被定义为遗传上不同的种群之间的杂交，越来越被认为是植物和动物中常见的现象，对理解物种形成过程很重要。虽然大多数物种形成可能是由于遗传交换的物理障碍，但这种分离并不总是绝对的，杂交的可能性始终存在。在灵长类动物中，在大多数主要的分类类群中已经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发现了古代杂交的片段。然而，杂交的机制及其在塑造灵长类动物进化史中的作用仍未得到解决。这项研究由博士生Kenneth Chiou（圣路易斯华盛顿大学）在Jane Phillips-Conroy博士的指导下进行，利用杂交作为一种“自然实验”来了解金达狒狒和灰足chacma狒狒遗传变异的空间结构，这些狒狒在赞比亚Kafue国家公园及其周围进行杂交。像人类一样，狒狒生活在不同的环境中，有着漫长的生活历史和复杂的社会组织，并且拥有一个共同的祖先，这使它们成为理解人类遗传变异全球模式的理想模型。利用最新的DNA测序技术，来自细胞核和线粒体基因组的数万个标记从杂交区域的个体中分型。这些标记被用来更好地理解本地适应和社会组织差异在种内、种间和种间杂交遗传变异结构中的作用。该研究为描述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次基因组研究之一，本研究增加了我们对自然杂交的理解，并为狒狒主要接触区的大面积区域提供了第一个遗传数据。DNA序列数据存储在公共数据库中，所有软件在开源许可下免费提供。通过为美国和国外的合作和推广创造机会，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.