Molecular Phylogenetics of Colubroid Snakes (Colubroidea)

确定不同类型的基因之间的遗传关系 高级蛇类是一个最困难和最具挑战性的问题。 的 蛇的身体结构被大大简化， 可以用来区分它们的字符，在许多情况下， 两个或两个以上的物种发展出相同的 独立的解剖学特征。 过去的依赖 因此，解剖学特征在 关于蛇的关系的可靠信息的方式。 整改 因此，有人提出，两个线粒体的DNA序列 基因可以从八个最大的 先进的蛇的推定群体，并为比较， 目的，从两个原始的蛇群。 dna序列 与解剖学比较相比， 对于这些研究。 一个是， 复杂性并没有反映在DNA水平上， 存在序列复杂度以用于确定 关系。 另一个是，与许多人的情况不同， 解剖学上的变化，几乎没有可能是相同的 序列变化将在两个不同物种中独立发生; 因此，与功能收敛，从那些由于家谱 传承 准确地了解基因之间的关系， 高级蛇类需要了解 一系列的特征在发展。 例如，确切地知道 无毒和有毒的蛇是如何联系在一起的 目前围绕这一发展的一些争议 毒液腺和分泌毒液的解剖结构。 这些知识也将为今后的研究奠定基础 蛇类之间的关系在这里没有被研究过。

Determining genetic relationships among the various kinds of advanced snakes is a most difficult and challenging problem. The greatly simplified body plan of snakes offers few anatomical characters that can be used to distinguish among them, and in many cases two or more species have developed the same sets of anatomical characteristics independently. The past reliance on anatomical characteristics has, therefore, provided little in the way of reliable information about snake relationships. To rectify this, it is proposed that the DNA sequences of two mitochondrial genes be obtained from representatives of the eight largest presumptive groups of advanced snakes and, for comparative purposes, from two primitive snake groups. DNA sequence comparisons offer two huge advantages over anatomical comparisons for these studies. One is that the reduction in anatomical complexity is not reflected at the DNA level; the full range of DNA sequence complexity is present for use in determining relationships. The other is that, unlike the case with many anatomical changes, there is almost no possibility that the same sequence changes will occur independently in two different species; thus, with functional convergences from those due to genealogical inheritance. An accurate knowledge of the genetic relationships among advanced snakes is required for understanding the ways in which suites of characteristics develop. For example, knowing exactly how non-poisonous and poisonous snakes are related will resolve some of the controversies that presently surround the development of venom glands and the anatomical components for delivering venom. This knowledge will also provide the foundation for future studies of relationships among snake groups not examined here.