Dissertation Research: Phylogenetic Analysis of the Snake Family Boidae Using mtDNA Sequence Data

小行星9310983 组成蛇科（爬行纲，有鳞目，蛇亚目）的属之间的关系尚不清楚。 这是可以理解的，因为蛇科之间的关系甚至亚目本身的起源都不确定。 Boidae科包含Boinae亚科、Calabariinae亚科、Erycinae亚科、Pythoninae亚科和Xenopeltinae亚科，并且基于眶上骨的存在而被定义为单系群（安德伍德1967）。 Boidae的几个分类已被提出，但成员属，属的分配或关系没有达成一致。 一些困难来自于神秘的分类群， 弯尾鱼属 和 卡拉巴里亚 ，其呈现出受到多种解释的形态特征。 本研究将改善这些问题，利用聚合酶链反应（PCR）扩增和核苷酸测序的ND4亚基的NADH脱氢酶基因的线粒体DNA（mtDNA）序列数据收集。 这些序列将为阐明这一主要脊椎动物群的进化历史提供至关重要的分子数据。 现有的标本可以覆盖Boidae科所有属的95%（19个属中的18个），包括有问题的分类群 卡拉巴里亚 和 弯尾鱼属 . 将使用系统发育分析使用简约法（PAUP）版本3.0，计算机程序（Swofford 1991）从序列中推断系统发育关系。 ND4基因来自 Leptotyphlops （家庭Leptotyphlopidae），推定的姐妹组的Boidae，已被测序的这一建议。 其他外类群包括巨蜥属 Varanus 蛇的种类 异齿兽属 （游蛇科）， 灯螺属 （游蛇科）， 小尾鱼属 （Elapidae）， 长蛇属 （Tropidophidae），和 Crotalus （蝰蛇科）。 来自游蛇科成员的数据已列入本提案。 从这项研究中获得的序列将提供一个强大的分子数据集，其框架将允许构建一个分类，可以与其他计划的基础上更传统的字符形成对比。 Boidae内的关系的分子评价将有助于这个非常成功的进化谱系的概念性理解，并提供必要的信息，以了解有鳞目的进化。%%% 该项目将使用DNA测序方法获得数据，使研究人员能够解决蛇科成员之间的更高层次的关系。 这些关系的知识将具有更广泛的相关性或重要性，因为蛇的起源和关系，一般来说，是未解决的，并且是一些争议的主题。***

9310983 Davis The relationships among genera comprising the family Boidae (Class Reptilia, Order Squamata, Suborder Serpentes) are not known. This is understandable in view of the uncertainties about relationships among snake families and even about the origins of the suborder itself. The family Boidae contains the subfamilies Boinae, Calabariinae, Erycinae, Pythoninae and Xenopeltinae and is defined as a monophyletic group based upon the presence of a supraorbital bone (Underwood 1967). Several classifications of the Boidae have been proposed, but there is no agreement on member genera, generic assignments or relationships. Some of the difficulties arise from enigmatic taxa such as Loxocemus and Calabaria , which present morphological characters that are subject to multiple interpretations. This study will ameliorate some of these problems by utilizing mitochondrial DNA (mtDNA) sequence data collected by polymerase chain reaction (PCR) amplification and nucleotide sequencing of the ND4 subunit of the NADH dehydrogenase gene. The sequences will provide molecular data crucial to elucidating the evolutionary history of this major vertebrate group. Available specimens allow coverage of 95% of all genera (18 of 19) in the family Boidae, including the problematic taxa Calabaria and Loxocemus . Phylogenetic relationships will be inferred from the sequences using the Phylogenetic Analysis Using Parsimony (PAUP)version 3.0, computer program (Swofford 1991). The ND4 gene from Leptotyphlops (Family Leptotyphlopidae), the putative sister group of the Boidae, has been sequenced for this proposal. Additional outgroups include the moni tor lizard genus Varanus and the snake genera Heterodon (Colubridae), Lampropeltis (Colubridae), Micrurus (Elapidae), Ungaliophis (Tropidophidae), and Crotalus (Viperidae). Data from members of the family Colubridae have been included in this proposal. The sequences obtained from this study will provide a robust molecular data set whose framework will allow construction of a classification that can be contrasted with other schemes which are based upon more traditional characters. The molecular evaluation of the relationships within the Boidae will contribute to the conceptual understanding of this very successful evolutionary lineage and provide information necessary to understanding Squamate evolution. %%% This project will use DNA sequencing methods to obtain data that will allow the investigators to address higher level relationships among members of the snake family Boidae. Knowledge of these relationships will be of broader relevance or importance because the origins and relationships of snakes, in general, are unresolved and the subject of some controversy. ***