Dissertation Research: A Phylogenetic Analysis of Desmognathine Salamanders Utilizing Ribosomal DNA Restriction Site Maps

形态数据还没有提供一个关于无肺火蜥亚科的一个单系亚科，即剑齿科的一个单系亚科的种间关系的清晰图景。RDNA限制酶切点变异的初步数据和其他脊椎动物的已发表数据表明，rDNA限制酶切点定位可以产生有价值的新的系统发育信息。利用Desmognasinae和Plethodontinae之间的姐妹群关系，将允许应用外群标准来确定原始或派生的限制酶切位点，并将基于对限制酶切点进化的最简明解释来制定系统发育假说。来自rDNA的系统发育信息可以为检验先前关于豆科动物生活史进化的假说提供基础，并可以用来确定豆科动物的祖先生活史，这是检验关于剑齿科无肺起源的相互竞争的假说的重要考虑因素。这项研究是首次对火蜥蜴单系类群中的整个rDNA阵列进行调查，并将增加对脊椎动物rDNA进化的了解。

Morphological data have not provided a clear picture of the relationships among species of the Desmognathinae a monophyletic subfamily of lungless salamanders, family Plethodontidae. Preliminary data on rDNA restriction site variation and published data from other vertebrate groups indicate that rDNA restriction site mapping can generate valuable new phylogenetic information for desmognathines. Use of the sister group relationship between the Desmognathinae and the Plethodontinae will allow application of the outgroup criterion for ascertaining primitive versus derived restriction sites, and a phylogenetic hypothesis will be formulated based ont he most parsimonious explanation of restriction site evolution. Phylogenetic information from rDNA can provide the basis for the testing of pervious hypotheses of life history evolution in desmognathines and can be used to determine the ancestral life history for desmognathines, an important consideration in testing competing hypotheses on the origin of lunglessness in the Plethodontidae. This study is the first investigation of the entire rDNA array in a monophyletic group of salamanders and will increase knowledge of rDNA evolution in vertebrates.