Mesozoic continental fragmentations and lizard radiations

完整或接近完整的线粒体DNA序列已被确定，从各种蜥蜴，代表主要家庭的目的有鳞目。连同以前发表的其他脊椎动物类群的有丝分裂基因组序列，我们进行了分子系统发育分析。可靠的系统发育关系已经建立了最大似然法和分歧时间估计使用贝叶斯方法，而不假设分子钟。根据这些分子结果和独立的地质和古生物学数据，我们的主要发现如下。1)主要蜥蜴科之间的分歧早于白垩纪大规模的大陆分裂，除了Agamidae和Chamaeleonidae之间的分歧可能发生在白垩纪中期。2)另一方面，大多数蛇类的家族辐射都晚于白垩纪/第三纪的界线。3)盘古大陆分裂成劳亚大陆和冈瓦纳大陆可能与蜥蜴的一些较浅的分歧有关，例如，和壁虎亚科之间的区别其他研究结果包括第一次表征的基因倒位在脊椎动物线粒体基因组中的脯氨酸tRNA基因的龙亚科无鞭毛。

Complete or nearly complete mitochondrial DNA sequences have been determined from various species of lizards that represent major families of the order Squamata. Together with previously published mitogenomic sequences of other vertebrate taxa, we have conducted molecular phylogenetic analyses. Reliable phylogenetic relationships have been established by the maximum-likelihood method and divergence times were estimated using a Baysian method without assuming the molecular clock. Biogeographic hypotheses were evaluated in light of these molecular results and independent geological and paleontological data Our major findings are the following. 1) Divergences between major lizard families predate the large-scale continental fragmentation during Cretaceous time, except for the divergence between Agamidae and Chamaeleonidae that likely occurred in the mid-Cretaceous. 2) On the other hand, most familial radiations of snakes postdate the Cretaceous/Tertiary boundary. 3) The break-up of Pangea into Laurasia and Gondwanaland may have been correlated with some shallower divergences of lizards, e.g., between Eublepharinae and Gekkoninae. Other findings include the first characterization of gene inversion in vertebrate mitochondrial geneomes in the proline tRNA gene of Draconinae agamids.