Dissertation Research: Molecular Phylogenetics of Neotropical Oryzomyine Rodents (Muridae: Sigmondontinae)

[801056]巴顿大鼠和小鼠亚科是南美洲最大的哺乳动物群，大约有250种占据了整个大陆的所有栖息地。这个多样化组合中的一个亚群是Oryzomyini，这是一个大约有15属100种的群体（“部落”），分布在安第斯高原的草原到亚马逊雨林。其中许多的分布范围很局限，需要加以保护；其他疾病传播广泛，并与人类疾病的媒介有关。这个部落中啮齿类动物之间的历史（系统发育）关系尚不确定；人们认为他们是北美移民的后裔。解决这些关系是一个复杂的问题，提出了重大的科学挑战。强有力的重建将为那些值得保护的物种（如加拉帕戈斯群岛特有的物种）以及那些与主要人类疾病有关的媒介（如汉塔病毒）提供一个明智的管理决策的历史框架。在本博士论文研究中，James L. Patton和学生Luis F. Garcia将主要通过比较线粒体和细胞核中几个基因的DNA序列来重建Oryzomyini的系统发育。“组合基因”方法应该在部落内所有分类水平上提供高分辨率的系统发育。系统发育应该允许研究人员测试一些流行的观点，关于这些啮齿动物何时何地首次在南美洲建立，以及它们在引入后如何多样化。

9801056 PATTON Rats and mice of the subfamily Sigmodontinae comprise the largest group of living mammals in South America, with some 250 species occupying all habitats throughout the continent. One of the subgroups of this diverse assemblage is the Oryzomyini, a group ("tribe") of about 15 genera and 100 species that occur from the grasslands of the high Andes to the Amazon rainforest. Many of these have highly localized ranges and are of conservation concern; others are widespread and have been implicated as vectors in human diseases. Little is certain about the historical (phylogenetic) relationships among rodents in this tribe; it is thought that they are descended from North American migrants. Resolving these relationships is a complex problem that presents a significant scientific challenge. A robust reconstruction would provide a historical framework for informed management decisions for those species of conservation concern (such as those endemic to the Galapagos Islands) as well as for those implicated as vectors in major human diseases (such as hanta virus). In this doctoral dissertation research, James L. Patton and student Luis F. Garcia will reconstruct the phylogeny of the Oryzomyini, principally by comparing DNA sequences from several genes in the mitochondrion and nucleus. The "combined gene" approach should provide high resolution of the phylogeny at all taxonomic levels within the tribe. The phylogeny should allow the researchers to test some prevailing ideas about when and where these rodents first became established in South America, and how they diversified after their introduction.