Systematics of Lipotyphlan Insectivores, An Early Lineage of Placental Mammals

9629319 ALLARD脂类目食虫动物（鼩、鼹鼠、刺猬及其近亲）是现存哺乳动物中最大的目之一。然而，这些食虫动物之间的系谱（系统发育）关系，以及脂类动物与其他哺乳动物群体之间的关系，仍然知之甚少。关于这些动物之间的关系，人们提出了几种不同的、相互竞争的解释。食虫动物是最早出现在化石记录中的哺乳动物之一，这表明食虫动物的不同谱系在该群体（以及一般哺乳动物）的历史早期就出现了分歧。可靠地重建古代生物群的系统发育关系比重建较新的生物群的系统发育关系要困难得多。在这项研究中，Marc C. Allard将采用多学科方法来研究脂肪类群系统发育的稳健重建问题。Allard将从所有食虫动物家族的代表中发现的线粒体和核基因中获得序列信息。这些序列将相互比较，并与其他哺乳动物群体的序列进行比较，并将用于构建系统发育树。基因序列将被单独和组合分析；此外，来自已发表的形态和解剖信息的数据将被编码，与基因序列数据一起包含在单个数据矩阵中，并用于系统发育重建。研究结果将为哺乳动物的早期历史和现代关系提供基本信息。

9629319 ALLARD The insectivores in the order Lipotyphla (shrews, moles, hedgehogs and their relatives) represent one of the largest orders of living mammals. However, the genealogical (phylogenetic) relationships among these insectivores, and between Lipotyphla and other groups of mammals, remain poorly understood. Several different and competing explanations for how these animals are related to each other have been suggested. Insectivores are among the first mammals to appear in the fossil record, suggesting that the various lineages of insectivores diverged early in the history of the group (and of mammals in general). It is more difficult to reliably reconstruct the phylogenetic relationships of ancient groups of organisms than of more recent ones. In this study, Marc C. Allard will use a multidisciplinary approach to investigate the problem of robustly reconstructing the phylogeny of Lipotyphla. Allard will obtain sequence information from mitochondrial and nuclear genes found in representatives of all families of insectivores. The sequences will be compared with each other and with sequences from other mammalian groups, and will be used to construct phylogenetic trees. The gene sequences will be analyzed individually and in combination; also, data from published morphological and anatomical information will be encoded, included in a single data matrix with the gene sequence data, and used in phylogenetic reconstructions. The results should provide fundamental information on the early history and present-day relationships of mammals.