Generic Relationships Among Dasyurid Marsupials Based on Mitrochondrial Cytochrome-b Sequences

达修罗是澳大利亚占主导地位的陆生食肉动物，栖息地多种多样，如荒原、森林和高山石南。它们是小型到中型哺乳动物，从微小的皮尔巴拉(209克)到狗大小的塔斯马尼亚魔鬼(6-8公斤)不等。Dasyuridae科约有17属51种，构成了澳大利亚有袋类动物的三个主要谱系之一。试图了解蝙蝠类之间的进化关系的努力可以追溯到20世纪初，但这些努力只能揭示系统发育的最广泛轮廓。近年来，对蝙蝠类分子遗传变异的比较研究揭示了该科内的亲缘关系，但尚未建立一个详细和明确的属间分枝顺序。这种缺乏系统发育的解决方案阻碍了理解达舒尔科动物的历史生物地理学，特别是新几内亚地方病的起源的努力。在这项研究中，将对所有蝙蝠属的代表进行线粒体细胞色素-b基因的DNA序列变异分析。细胞色素b是细胞能量产生的关键成分，是一种相对较小(约400个残基)的简单分子。以蝙蝠属为代表的细胞色素-b的DNA变异模式在不同的分化时间范围内，将允许构建基因如何进化的简单模型。在现代分子系统学中，这样一个模型对系统发育的估计价值是一个关键问题。这些数据和模型将提供一种有趣的方法来比较几种当前和概念上截然不同的系统发育推断方法。最终的结果应该会提供更清晰的蝙蝠属关系图景，以及对细胞色素-b进化和分子系统学的更好理解。

Dasyurids are the dominant terrestrial carnivores of Australia, occupying a diverse array of habitats such as aridlands, forest, and alpine heath. They are small to medium sized mammals, ranging from the tiny Pilbara ningaui (209 g) to the dog-sized Tasmanian devil (6-8 kg). With approximately 51 species in 17 genera, the family Dasyuridae constitutes one of three major lineages of Australasian marsupials. Attempts to understand the evolutionary relationships among dasyurids date from the early 20th century, but these efforts could only reveal the broadest outlines of phylogeny. In recent years, comparative study of molecular genetic variation among dasyurids has shed much light on relationships within the family, but a detailed and well-resolved branching order for genera has not been established. This lack of phylogenetic resolution has hampered efforts to understand the historical biogeography of dasyurids, particularly the origins of New Guinean endemics. In this study, DNA sequence variation in the mitochondrial cytochrome-b gene will be assayed for representatives of all dasyurid genera. Cytochrome-b, a key component in cellular energy production, is a relatively small (ca. 400 residues) and simple molecule. Patterns of DNA variation in cytochrome-b across the range of divergence times represented by dasyurids will allow construction of a simple model of how the gene evolves. The value of such a model for estimating phylogeny is a key issue in modern molecular systematics. The data and model together will provide an interesting means of comparing several current and conceptually distinct methods of phylogenetic inference. Final results should provide a clearer picture of dasyurid relationships, as well as a better understanding of cytochrome-b evolution and molecular phylogenetics.