Reeder T W
Department of Zoology, University of Texas at Austin 78712-1604, USA.
Mol Phylogenet Evol. 1995 Jun;4(2):203-22. doi: 10.1006/mpev.1995.1020.
The phylogenetic relationships among 40 species, representing all genera, within the North American lizard family Phrynosomatidae were inferred from mitochondrial ribosomal RNA gene sequences. Cladistic analysis of the DNA sequence data (779 bp; 162 informative characters) supported the monophyly of the sand lizards (Callisaurus, Cophosaurus, Holbrookia, and Uma), Petrosaurus, Phrynosoma, Urosaurus, and Uta. All the species of Sceloporus, except S. variabilis and S. chrysostictus, formed a clade. Except for a sand lizard + Phrynosoma clade, the intergeneric relationships inferred from the mtDNA were largely incongruent with recent cladistic analyses based on morphology. Sceloporus group monophyly was not supported, with Petrosaurus being a member of a clade containing Sator, Sceloporus, and Urosaurus, to the exclusion of Uta. The phylogenetic placement of Uta was ambiguous. The substitutional bias in the phrynosomatid mitochondrial rDNA sequences was examined, as well as the phylogenetic information content of transitions relative to transversions. There appeared to be a lower transition bias than observed in other vertebrate sequences, with some classes of transversions occurring as frequently as G <-> A transitions. Transitions were no less informative for phylogeny reconstruction than transversions. Therefore, transitions should not be down-weighted in phylogenetic analysis, as is often done.
基于线粒体核糖体RNA基因序列推断了北美蜥蜴科角蜥科内代表所有属的40个物种之间的系统发育关系。对DNA序列数据（779 bp；162个信息性特征）进行的分支分析支持了沙蜥属（Callisaurus、Cophosaurus、Holbrookia和Uma）、岩蜥属、角蜥属、强棱蜥属和犹他蜥属的单系性。强棱蜥属的所有物种，除了变色强棱蜥和金点强棱蜥，形成了一个分支。除了一个沙蜥属+角蜥属分支外，从线粒体DNA推断出的属间关系与最近基于形态学的分支分析在很大程度上不一致。强棱蜥类群的单系性未得到支持，岩蜥属是一个包含萨托蜥属、强棱蜥属和强棱蜥属的分支的成员，不包括犹他蜥属。犹他蜥属的系统发育位置不明确。研究了角蜥科线粒体核糖体DNA序列中的替换偏差，以及转换相对于颠换的系统发育信息含量。与其他脊椎动物序列相比，转换偏差似乎较低，某些类型的颠换发生频率与G <-> A转换一样高。转换在系统发育重建中的信息性并不比颠换少。因此，在系统发育分析中，转换不应像通常那样被低估。
