Phylogeny of Didelphid Marsupials, a Taxon-Dense Approach Using Data from Nuclear Genes and Morphology

明尼苏达大学的Sharon Jansa和Robert S.沃斯在纽约的美国自然历史博物馆研究南美双头负鼠有袋类动物的进化历史，这种动物通常被称为新大陆负鼠。" 现存的16属有袋类动物包括75种，代表了南美洲古老的地方性哺乳动物区系中最多样化的幸存谱系;今天，这些物种构成了澳大利亚以外唯一基本完整的有袋类哺乳动物辐射。 虽然双头龙长期以来一直受到地理学家和比较生物学家的关注，但它们的进化历史仍然知之甚少。 这个项目的主要目标是推断有袋类动物之间的历史关系，以便为解释它们的进化和历史地理学提供一个安全的框架。 我们将收集和分析DNA序列数据从五个，缓慢进化的核基因与广泛的生化功能的核心组的42种代表所有16属的didelphid有袋动物。 由此产生的8个酶数据集将是这些物种的最大的比较分子数据集，并将为重建其进化史提供关键数据，除其他应用外，这项研究的结果将有助于南美洲的历史地理学研究，为理解有袋动物的形态进化提供一个框架，并为未来在比较生物学和古生物学中使用didelphid样本提供信息。 此外，由此产生的DNA序列数据库将为理解基因功能和哺乳动物辐射中分子进化的动力学提供材料。 在哺乳动物系统学和分子进化研究中，双足目有袋类长期被忽视。 这项研究的结果将填补我们对哺乳动物进化生物学理解的一个明显空白。

A grant has been Sharon Jansa at the University of Minnesota and Dr. Robert S. Voss at the American Museum of Natural History, New York to study the evolutionary history of South American didelphid marsupials (Didelphimorphia: Didelphiadae), commoly known as New World "opossums." The16 extant genera of didelphid marsupials comprise 75 species and represent the most diverse surviving lineage of the old endemic mammalian fauna in South America; today these species constitute the only substantially intact radiation of marsupial mammals outside Australasia. While didelphids have long been of interest to biogeographers and comparative biologists, their evolutionary history remains poorly understood. The principal goal of this project is to infer the historical relationships among didelphid marsupials in order to provide a secure framework for interpreting their evolution and historical biogeography. We will collect and analyze DNA sequence data from five, slowly-evolving nuclear genes with a wide range of biochemical functions for a core group of 42 species representing all 16 genera of didelphid marsupial. The resulting 8 kilobase dataset will be the largest comparative molecular dataset for these species and will provide critical data for reconstructing their evolutionary history.Among other applications, the results of this study will contribute to historical biogeographic research in South America, provide a framework for understanding the morphological evolution of marsupials, and inform the future use of didelphid exemplars in comparative biology and palaeontology. In addition, the resulting database of DNA sequences will provide materials for understanding gene function and the dynamics of molecular evolution in mammalian radiations. Didelphid marsupials have long been overlooked in studies of mammalian systematics and molecular evolution. The results of this study will fill a conspicuous gap in our understanding of mammalian evolutionary biology.awarded to Dr.