Phylogenetics of Rodents: Molecular Systematics of the Suborder Hystricognathi and Related Families

啮齿类动物是世界范围内哺乳动物多样性的重要组成部分。它们在形态、栖息地利用、行为、生活史策略和生物地理分布方面表现出相当大的差异。在DNA序列水平上，啮齿动物表现出比其他哺乳动物更快的总体变化速度，核苷酸替代率的增加与世代时间和总体突变率的差异有关。这项由罗德尼·霍尼卡特（Rodney Honeycutt）进行的研究有两个目的。首先，我们将利用来自三个核基因和一个线粒体基因的核苷酸序列数据来研究Histricognathi亚目啮齿动物之间的关系。这个亚目包含了啮齿动物多样性的一个大子集，包括大多数啮齿动物科。组齿目啮齿类动物主要分布在非洲和南美洲，在南美洲，它们代表了哺乳动物辐射的一个独特部分。其次，这些核苷酸序列数据和由此产生的基因树将用于检查分子水平上的变化模式。一些待研究的模式涉及核苷酸取代率的异质性与几个参数（包括体型、代谢率和世代时间）之间的相关性。为了确定啮齿动物的基因是否经历了与其他哺乳动物不同类型的取代，将与其他非啮齿动物哺乳动物群体中所见的核苷酸取代分布和所有这些基因的变化率进行比较。

9615163 HONEYCUTT Rodents represent a major component of mammalian diversity worldwide. They demonstrate considerable variation in morphology, habitat utilization, behavior, life history strategies, and biogeographic distribution. At the DNA sequence level, rodents demonstrate faster overall rates of change than seen for other groups of mammals, and this increase in nucleotide substitution rate has been linked to differences in generation time and overall mutation rates. The purpose of this research, to be conducted by Rodney Honeycutt, is twofold. First, nucleotide sequence data from three nuclear genes and one mitochondrial gene will be used to investigate relationships among rodents in the suborder Histricognathi. This suborder encompasses a large subset of rodent diversity, including a majority of rodent families. Histricognath rodents occur primarily in Africa and South America, and within South America they represent an unique part of the mammalian radiation. Second, these nucleotide sequence data and the resulting gene trees will be used to examine patterns of change at the molecular level. Some of the patterns to be investigated pertain to correlation's between heterogeneity in the rate of nucleotide substitution and several parameters including body size, metabolic rate, and generation time. In an effort to determine whether or not rodent genes experience different classes of substitutions relative to other mammals, both the distribution of nucleotide substitutions throughout each gene and rates of change in all these genes will be compared to those seen in other non-rodent mammal groups.