Biogeography of Malagasy Carnivores

[9807045 . YODER]马达加斯加的食肉哺乳动物没有像岛上其他哺乳动物那样被广泛研究，但它们是这个独特动物群的重要组成部分。食肉动物入侵过这个岛多少次？他们是如何到达那里的？他们从哪里来？有没有马达加斯加的食肉动物迁徙回大陆？了解马达加斯加食肉动物的历史（系统发育）将有助于回答这些以及其他有关这些动物的生物学和分布的问题。在这项研究中，Anne Yoder和她的同事John Flynn和Michael Nedbal将获取和分析DNA序列数据，来自两个线粒体基因和两个核基因的部分，这些数据来自马达加斯加食肉动物。根据这些数据，将重建这些食肉动物的历史（系统发育）关系；分析将包括居住在其他地方的被认为是马达加斯加食肉动物近亲的食肉动物物种，因此可能属于马达加斯加食肉动物出现的谱系。在某些情况下，DNA序列数据可以用作“分子钟”来估计重大事件的日期。食肉动物的数据将被评估，看看这样的估计是否合适，如果是，那么食肉动物在马达加斯加定居的地质日期将被提出。随着对马达加斯加陆生脊椎动物其他谱系的了解越来越多，这些调查的结果将变得越来越重要。例如，如果我们发现不同的种群可能以很宽的间隔出现，并且这些间隔之间没有明显的模式，那么对马达加斯加如何成为动物栖息地的最好解释就是它是偶然的；创始人乘坐被冲到岛上海岸上的倒下的原木或其他“木筏”，每隔一段时间就到达一次。另一方面，如果所有的种群都是在相对较短的时间内出现的，那么马达加斯加岛的人口分布机制就不那么随机，很可能与地质事件有关。例如，动物到达马达加斯加的离散间隔，加上马达加斯加和另一块陆地之间的一系列岛屿的地质证据，表明动物在这些岛屿之间“跳跃”，在马达加斯加定居。

9807045 YODER The carnivorous mammals of Madagascar have not been studied as extensively as other mammals on this island, yet are an important component of this unique fauna. How many times have carnivores invaded the island? How did they get there? From where did they come? Have any Madagascar carnivores ever migrated back to mainland areas? An understanding of the history (phylogeny) of Madagascar carnivores should help answer these and other questions about the biology and distribution of these animals. In this research, Anne Yoder and her colleagues John Flynn and Michael Nedbal will acquire and analyze DNA sequence data, from two mitochondrial genes and portions of two nuclear genes, collected from the species of Madagascar carnivores. From these data, the historical (phylogenetic) relationships of these carnivores will be reconstructed; the analysis will include carnivore species inhabiting other places that are presumed to be the closest relatives of the Madagascar carnivores, and thus may belong to lineages from which Madagascar carnivores appeared. In some cases, DNA sequence data can be used as a "molecular clock" to estimate dates for major events. The carnivore data will be evaluated to see if such estimations are appropriate, and if so, then geologic dates for carnivore colonization(s) of Madagascar will be proposed. The results of these investigations will become increasingly important as more is learned about other lineages of Madagascar's terrestrial vertebrates. If, for example, it is found likely that different groups appeared at widely spaced intervals and without obvious patterning to the intervals, then the best explanation for how Madagascar became populated with animals would be that it was haphazard; founders arrived on fallen logs or other "rafts" washed up at irregular intervals on the island's shore. If, on the other hand, all groups are estimated to have appeared within a relatively short time period, then a less random mechanism for populating Ma dagascar, likely tied to geological events, would be favored. For example, a discrete interval for animal arrival on Madagascar coupled with geological evidence for a chain of islands between Madagascar and another land mass would suggest that the animals "hopped" among these islands to colonize Madagascar.