Biodiversity Institute and Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045-7561, USA.
Mol Phylogenet Evol. 2010 May;55(2):699-710. doi: 10.1016/j.ympev.2010.01.027. Epub 2010 Feb 2.
In the Philippines, Pleistocene sea level oscillations repeatedly connected and isolated neighboring islands. Hence, an understanding of the island platforms adjoined during periods of low sea level has led biologists to a suite of expectations that, taken together, represent a paradigm for the process of recent diversification in southeast Asia. We employ statistical tests of phylogenetic topology and population genetic analyses of widespread species of bent-toed geckos (Cyrtodactylus) to ascertain whether patterns of inter- and intra-specific diversity can be explained by a Pleistocene aggregate island model of diversification. Contrary to many classic studies of Philippine vertebrates, we find complex patterns that are only partially explained by past island connectivity. In particular, we determine that some populations inhabiting previously united island groups show substantial genetic divergence and are inferred to be polyphyletic. Additionally, greater genetic diversity is found within islands, than between them. Among the topological patterns inconsistent with the Pleistocene model, we note some similarities with other lineages, but no obviously shared causal mechanisms are apparent. Finally, we infer well-supported discordance between the gene trees inferred from mitochondrial and nuclear DNA sequences of two species, which we suspect is the result of incomplete lineage sorting. This study contributes to a nascent body of literature suggesting that the current paradigm for Philippine biogeography is an oversimplification requiring revision.
在菲律宾，更新世海平面的波动反复连接和隔离了邻近的岛屿。因此，对低海平面时期连接在一起的岛屿平台的理解，使生物学家对一系列的预期有了深入的了解，这些预期共同代表了东南亚近期多样化过程的范例。我们运用系统发育拓扑结构的统计检验和广泛分布的弯趾壁虎（Cyrtodactylus）物种的种群遗传分析，来确定种间和种内多样性的模式是否可以用更新世聚合岛屿多样化模型来解释。与许多菲律宾脊椎动物的经典研究相反，我们发现了复杂的模式，这些模式仅部分可以用过去的岛屿连通性来解释。特别是，我们确定了一些居住在以前联合的岛屿群中的种群表现出明显的遗传分歧，并推断它们是多系的。此外，岛屿内部的遗传多样性大于岛屿之间的遗传多样性。在与更新世模型不一致的拓扑模式中，我们注意到与其他谱系的一些相似之处，但显然没有明显的共同因果机制。最后，我们推断出两种物种的线粒体和核 DNA 序列推断出的基因树之间存在很好支持的分歧，我们怀疑这是不完全谱系分选的结果。这项研究有助于形成一个新兴的文献体系，表明菲律宾生物地理学的当前范例过于简单化，需要进行修订。
