RPG: Phylogeny and Evolution of Mitochondrial DNA in ExtinctMalagasy Primates

这项拟议的研究项目将利用古代脱氧核糖核酸(A-脱氧核糖核酸)技术，以了解已灭绝灵长类的不同组合的进化起源和灭绝。线粒体DNA将被提取、扩增和测序，用于马达加斯加亚化石狐猴的全面样本。被测试的样品的年龄范围从现在之前的大约650年(b.p.)公元前一万多年。DNA序列将用系统发育、分子进化和种群遗传学的方法进行分析，以重建大型灭绝狐猴与小型现存狐猴的进化关系，并调查导致这些独特哺乳动物灭绝的力量。单个物种谱系内的时间间隔DNA序列的比较将允许实时观察分子进化模式，从而为分子进化领域提供了一个新的视角。研究DNA序列和结构随时间的变化(即分子进化)是一个越来越有价值的科学研究领域。这类研究的应用领域非常广泛，如分析和控制有机病原体(例如，艾滋病病毒)、生物地理学、系统发育学、生理学和保护生物学-仅举几例。在A-DNA研究人员群体中正在开发的技术允许科学家直接观察DNA结构的变化，这些变化以前被限制在通过比较活的生物的DNA来推断的领域。尽管没有真正的理论或概念原则来统一A-DNA学科，但所采用的严格和困难的实验室方法已经创建了一个研究人员社区，对他们来说，相互交流是必不可少的。这项拟议的研究将增加这一不断增长的知识体系，并将从已灭绝的非人类灵长类动物中产生史无前例的DNA序列数据。问题将同时在宏观和微观进化层面上解决，从而超越“技术好奇心”来分析更大的问题。首先，该项目将有助于恢复马达加斯加所有地方性灵长类动物的系统发育。这一目标的实现对于了解马达加斯加和非洲的生物地理历史以及了解极为多样化的哺乳动物群体的形态和生态进化具有重要意义。其次，该项目将允许对分子进化现象进行细粒度分析，如突变率和核苷酸替换模式。第三，在已知的灭绝窗口内对种群内遗传多样性进行时间间隔采样，可以通过识别遗传同质性的危险水平来帮助指导未来的保护工作。

Yoder 9707559 RPG The proposed research project will exploit ancient-DNA (A-DNA) techniques in order to understand the evolutionary origins and demise of a diverse assemblage of extinct primates. Mitochondrial DNA will be extracted, amplified, and sequenced for a comprehensive sample of subfossil Malagasy lemurs. The samples to be tested range in age from approximately 650 years before present (b.p.) to more than 10,000 years b.p. DNA sequences will be analyzed with phylogenetic, molecular evolutionary, and population genetic methods in order to reconstruct the evolutionary relationships of the large-bodied extinct lemurs relative to the smaller-bodied extant lemurs and in order to investigate the forces that led to the extinction of these unique mammals. The comparison of time-interval DNA sequences within a single species lineage will permit the observation of molecular evolutionary patterns in "real time", thus contributing a novel perspective to the field of molecular evolution. The study of changes in DNA sequence and structure over time (i.e.,molecular evolution) is an increasingly valuable field of scientific investigation. Such studies have applications for fields as diverse as the analysis and control of organic pathogens (e.g., the AIDS virus), biogeography, phylogenetics, physiology, and conservation biology --- just to name a few. The techniques that are being developed within the community of A-DNA researchers permit scientists to directly observe changes in DNA structure that had previously been confined to the realm of extrapolation through the comparison of DNA from living organisms.Although there is no real theoretical or conceptual principle that unites the A-DNA discipline, the stringency and difficulty of the laboratory methods that are employed has created a community of researchers for whom intercommunication is essential. The proposed research will add to this growing body of knowledge and will generate an unprecedented amount of DNA seque nce data from extinct, non-human primates. Questions will be addressed on both macro- and microevolutionary levels, thereby going beyond "technological curiosity" to analyze larger questions. First, the project will contribute to the goal of recovering the phylogeny of all endemic Malagasy primates. The achievement of this goal is significant for understanding the biogeographic history of Madagascar and Africa as well as for understanding morphological and ecological evolution in an extremely diverse assemblage of mammals. Second, the project will allow a fine-grained analysis of molecular-evolutionary phenomena such as mutation rate and patterns of nucleotide substitutions. Third, time-interval sampling of intra-population genetic diversity throughout a known extinction window could help guide future conservation efforts by identifying dangerous levels of genetic homogeneity.