Doctoral Dissertation Research: Natural Hybridization Between Red-tailed Monkeys (Cercopithecus ascanius) and Blue Monkeys (Cercopithecus mitis) in Gombe National Park, Tanzania

这个项目正在使用一个“自然实验”来研究一个很少被考虑的进化现象，更不用说在野外研究了，但它可能在生命史上非常重要。物种被认为是自然多样性的基本单位，应该遵循单向进化轨迹，首先在身体上孤立，然后在生殖上孤立。在这个关键点之后，一个物种在遗传上是独立的;它只能通过突变获得新的变异和进化的潜力。一个新的物种生存下来，通过雕刻自己的一片生态空间来做到这一点，并且在这样做的过程中，它的行为和适应能力往往变得更加狭窄，更加专业化。毫无疑问，这种典型模式在进化的多样化过程中是常见的，也是核心的。 然而，一些证据表明，物种形成过程并不总是不可逆转的;在不寻常的情况下，但并非不可能罕见，无可争议地属于不同物种的种群可以通过融合消除生殖障碍并形成一个新物种。 一旦完成，这种融合比传统的分裂物种形成更难识别。事实上，最好的证据往往来自直到最近才获得的分子遗传信息。 该项目利用观察数据和遗传数据来检验一种假设，即坦桑尼亚国家公园的贡贝两种猴子的种群正处于这一过程之中。 红尾猴（Cercopithecus ascanius）和蓝猴（C.mitis）是很好的物种，在外观和行为上都很不同。在这两种植物出现的大部分地区，它们很少杂交，杂交显然是不成功的。然而，在贡贝国家公园，经过多代的杂交，杂交种在繁殖种群中占了相当大的少数。这项研究正在验证一个假设，即贡贝不寻常的地理和人口条件促使这两个物种在遗传和行为上融合。 Co-PI的实地调查将量化亲本物种和杂交物种的密度，并将其与森林生境的分布联系起来。行为数据将被用来测试的推测，在贡贝这两个C.mitis和C.ascanius往往涉及杂交，和其他物种的成员，与行为通常保留同种。 这项研究的遗传学阶段将利用最近的技术进步，允许从“生物碎屑”（如粪便）中回收遗传物质。 这两种猴子特有的遗传标记将用于追踪贡贝种群中单个猴子的祖先，从而推断种群之间以及进入杂交种的基因流动模式。 由此产生的博士学位将使一名具有良好教学和公共服务记录的女科学家有资格进入学术界。实地工作本身涉及国际合作，以及在东道国坦桑尼亚对人员进行实际科学培训。更广泛地说，它还应该有助于向公众宣传生物进化的本质。

This project is using a "natural experiment" to investigate an evolutionary phenomenon that has rarely been considered, let alone studied in the field, yet which may have been of great importance in the history of life. Species, considered the basic units of natural diversity, are supposed to follow a one-way evolutionary trajectory, becoming isolated first physically, then reproductively. After that crucial point, a species is genetically independent; it can acquire new variation, and the potential to evolve, only via mutation. A new species that survives does so by carving itself a slice of ecological space, and in doing so often becomes narrower, more specialized, in its behavior and adaptations. This canonical pattern is undoubtedly frequent and central to the process of evolutionary diversification. Some evidence suggests, however, that the speciation process is not always irreversible; that under circumstances that are unusual, but not impossibly rare, populations belonging indisputably to different species can dissolve the reproductive barrier and form a new species by fusion. Once completed, such fusions are much harder to recognize than instances of conventional, splitting speciation. Indeed, the best evidence for them often comes from molecular genetic information of a kind unavailable until very recently. This project uses both observational and genetic data to test the hypothesis that populations belonging to two species of monkeys in the Gombe National Park, Tanzania, are in the midst of such a process. Red-tailed monkeys (Cercopithecus ascanius) and blue monkeys (C.mitis) are good species, quite distinct in appearance and behavior. Over most of the broad area where both occur, they rarely hybridize, and hybrids are apparently unsuccessful. In Gombe National Park, however, interbreeding over many generations has established hybrids as a substantial minority within the breeding population. The study is testing the hypothesis that unusual biogeographic and demographic conditions at Gombe have driven the two species towards genetic and behavioral integration. The Co-PI's field survey will quantify the density of parental species and hybrids, and relate these to the distribution of forest habitat. Behavioral data will be used to test the speculation that at Gombe both C.mitis and C.ascanius tend to relate to hybrids, and members of the other species, with behaviors normally reserved for conspecifics. The genetic phase of the study will take advantage of recent technical advances that allow genetic material to be recovered from "biodetritus" - such as feces. Genetic markers specific to the two monkey species will be used to track the ancestry of individual monkeys in the Gombe population, and hence infer the patterns of gene flow between the populations and into the hybrids. The resulting PhD will qualify a female scientist, with a proven teaching and public service record, to enter the academic community. The fieldwork itself involves international collaboration, and practical scientific training of personnel in the host country, Tanzania. More broadly, it should also help to inform the general public about the nature of biological evolution.