Doctoral Dissertation Improvement: Phylogenetic Relationships and Gene Flow Among Southern African Baboons

普通狒狒（Papio）由一系列地理上不同的形式或“半物种”组成，虽然在外观和行为上彼此不同，但已知在它们的活动范围相遇的地方会在野外杂交。Papio在研究影响近亲杂交物种进化的分化和网状过程中特别有用，因为狒狒是唯一一种我们拥有详细的行为、遗传和形态学数据以及杂交动力学长期研究的灵长类动物。除此之外，对Papio的研究可以提供更直接的见解，以了解进化物种，如早期人属，占据类似的穴居类。狒狒和早期人类一样，是在非洲更新世的热带稀树草原和林地中进化而来的陆生、生态多面手灵长类动物。这些环境中气候驱动的变化影响了Papio的进化，很可能也影响了人属。然而，狒狒保留了这些事件发生时间和地理位置的遗传特征，而最近进化的现代人已经失去了这些特征。目前对Papio进化的了解主要来自对东非狒狒的研究。然而，目前尚不清楚这些东非狒狒是否代表了整个巴布亚。因此，这项研究将集中在南部非洲的进化关系和基因流动模式上，黄色狒狒和chacma狒狒，它们在赞比亚中部相互接触。这两种形式的种群之间的进化关系将从线粒体DNA序列数据推断出来，而种群之间的遗传交换将使用线粒体DNA和一系列核基因组微卫星标记来识别。这项研究解决的问题包括：非洲南部狒狒种群之间的关系是什么？这两种形式杂交了吗？如果杂交了，产生的基因流是什么模式？这种基因交换是由雄性从其出生群体分散到其他附近群体所驱动的吗，就像在东非一样？这些问题的答案将有助于澄清Papio的分类，提高我们对狒狒物种之间关系的理解以及影响其进化的因素，并为这些过程如何影响类似灵长类物种的进化提供见解。狒狒通常用于生物医学、行为和基因研究。准确了解这些重要模式生物之间的进化关系是进行此类研究的必要条件。本项目将为联合项目负责人和本科生提供科学培训机会。它还将促进美国和赞比亚科学家之间的专业接触和合作，这一直不是生物人类学家研究的传统地理焦点。

Common baboons (Papio) comprise a series of geographically distinct forms or 'semi-species' that, while recognizably different from one another in appearance and behavior, are known to hybridize in the wild where their ranges meet. Papio is particularly useful in the study of the processes of divergence and reticulation that affect the evolution of closely-related, hybridizing species because baboons are the only primates for which we have detailed behavioral, genetic, and morphological data as well as long-term research in the dynamics of hybridization. In addition to this, studies of Papio can provide more direct insight into the evolution species, like early Homo, that occupy similar econiches. Baboons, like early Homo, are terrestrial, ecologically generalist primates that evolved in the savannas and woodlands of Pleistocene Africa. The climate-driven changes in these environments that affected the evolution of Papio may well have impacted Homo. However, baboons retain the genetic signature of the timing and geographic placement of these events that more recently evolved modern humans have lost.Current knowledge of the evolution of Papio largely comes from studies of eastern African baboons. However, it is unclear if these eastern African baboons are representative of Papio as a whole. This study, therefore, will focus on the evolutionary relationships and patterns of gene flow among southern African forms, the yellow and chacma baboons, which come into physical contact with one another in central Zambia. The evolutionary relationships among populations of these two forms will be inferred from mitochondrial DNA sequence data, while genetic exchange between populations will be discerned using both mitochondrial DNA and an array of nuclear genomic microsatellite markers. Questions addressed by this research include: what are the relationships among populations of southern African baboons? Do these two forms hybridize, and if so, what pattern does the resulting gene flow take? Is this genetic exchange driven by the dispersal of males from their natal groups into other nearby groups, as in eastern Africa? Answers to these questions will help clarify the taxonomy of Papio, improve our understanding of the relationships among baboon species and the factors that have affected their evolution, and provide insight into how such processes may impact the evolution of similar primate species.Baboons are commonly used in biomedical, behavioral, and genetic research. An accurate understanding of the evolutionary relationships among these important model organisms is necessary for such studies. This project will provide scientific training opportunities for the co-PI and undergraduate students. It will also promote professional contact and collaboration between scientists in the United States and Zambia, which has not been a traditional geographical focus of research by biological anthropologists.