DISSERTATION RESEARCH: The phylogenetic history of Plestiodon and a new empirical perspective on multi-locus molecular dating methods

研究人员早就认识到精确的分子钟对重要进化事件的潜在解释力。不幸的是，现在人们认识到，分子进化往往不是以时钟的方式进行的，更复杂的弛豫时钟方法正在开发中。 本研究的一个主要目标将是评估的假设和行为，新开发的松弛时钟发散测年方法的背景下，20个轨迹的经验数据集的scincid蜥蜴属Plestiodon。Plestiodon蜥蜴是生物学研究的一个常见课题，居住在美国大部分地区，但对它们的进化历史知之甚少。识别和确定过去的生物事件是进化生物学的一个基本目标。年代学是分析历史地理学的核心，也是阐明形态结构、行为或生理进化速度的核心。此外，重要的是要确定关键的进化事件的日期，无论它们是灭绝事件，历史上的人类迁移事件，还是与疾病爆发有关的流行病事件。 这项研究的结果调查最近开发的分子测年方法的性能将适用于整个领域的分子分歧测年，并将提高生物学家的能力，以估计重要的生物事件的时间。

Researchers have long recognized the potential explanatory power of precise molecular clocks for placing dates on important evolutionary events. Unfortunately, it is now recognized that molecular evolution often does not proceed in a clock-like fashion and development of more complex relaxed-clock methods is ongoing. A major goal of this study will be to evaluate the assumptions and behavior of newly developed relaxed-clock divergence dating methodologies in the context of a 20-locus empirical data set for the scincid lizard genus Plestiodon. Plestiodon lizards are a common subject of biological research and inhabit most of the United States, yet little is known about their evolutionary history. Identifying and dating biological events in the past is a fundamental goal of evolutionary biology. Chronology is central to analyses of historical biogeography, as well as to efforts to elucidate the rate at which a morphological structures, behaviors, or physiologies have evolved. It is furthermore important to place dates on critical evolutionary events, whether they be extinction events, historical human migration events, or epidemiological events associated with disease outbreak. The results of this research investigating the performance of recently developed molecular dating methodologies will be applicable to the entire field of molecular divergence dating and will improve the ability of biologists to estimate the timing of important biological events.