Department of Biology, Boston University, Boston, MA 02215, USA.
Biol Lett. 2012 Oct 23;8(5):783-6. doi: 10.1098/rsbl.2012.0331. Epub 2012 May 16.
We present the first genomic-scale analysis addressing the phylogenetic position of turtles, using over 1000 loci from representatives of all major reptile lineages including tuatara. Previously, studies of morphological traits positioned turtles either at the base of the reptile tree or with lizards, snakes and tuatara (lepidosaurs), whereas molecular analyses typically allied turtles with crocodiles and birds (archosaurs). A recent analysis of shared microRNA families found that turtles are more closely related to lepidosaurs. To test this hypothesis with data from many single-copy nuclear loci dispersed throughout the genome, we used sequence capture, high-throughput sequencing and published genomes to obtain sequences from 1145 ultraconserved elements (UCEs) and their variable flanking DNA. The resulting phylogeny provides overwhelming support for the hypothesis that turtles evolved from a common ancestor of birds and crocodilians, rejecting the hypothesized relationship between turtles and lepidosaurs.
我们进行了首次基于超过 1000 个来自包括大蜥蜴目物种在内的所有主要爬行动物类群代表的基因组尺度的分析，以解决龟鳖类在系统发育中的位置问题。先前的形态特征研究将龟鳖类定位在爬行动物树的基部或与蜥蜴类、蛇类和大蜥蜴目（有鳞目）在一起，而分子分析通常将龟鳖类与鳄类和鸟类（主龙类）联系在一起。最近对共享 microRNA 家族的分析发现，龟鳖类与有鳞目更为接近。为了用来自基因组中分散的许多单拷贝核基因座的大量数据来检验这一假说，我们使用序列捕获、高通量测序和已发表的基因组，从 1145 个超保守元件（UCEs）及其可变侧翼 DNA 中获得序列。该系统发育树为龟鳖类是从鸟类和鳄类的共同祖先演化而来的假说提供了压倒性的支持，从而否定了龟鳖类与有鳞目之间的假定关系。
