Yoshizawa Kazunori, Johnson Kevin P
Systematic Entomology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
Mol Phylogenet Evol. 2005 Nov;37(2):572-80. doi: 10.1016/j.ympev.2005.05.008. Epub 2005 Jul 7.
The order Zoraptera (angel insects) is one of the least known insect groups, containing only 32 extant species. The phylogenetic position of Zoraptera is poorly understood, but it is generally thought to be closely related to either Paraneoptera (hemipteroid orders: booklice, lice, thrips, and bugs), Dictyoptera (blattoid orders: cockroaches, termites, and mantis), or Embioptera (web spinners). We inferred the phylogenetic position of Zoraptera by analyzing nuclear 18S rDNA sequences, which we aligned according to a secondary structure model. Maximum likelihood and Bayesian analyses both supported a close relationship between Zoraptera and Dictyoptera with relatively high posterior probability. The 18S sequences of Zoraptera exhibited several unusual properties: (1) a dramatically increased substitution rate, which resulted in very long branches; (2) long insertions at helix E23; and (3) modifications of secondary structures at helices 12 and 18.
缺翅目（天使昆虫）是鲜为人知的昆虫类群之一，仅包含32个现存物种。缺翅目的系统发育位置了解甚少，但一般认为它与副翅总目（半翅类目：书虱、虱子、蓟马和蝽象）、蜚蠊目（蜚蠊类目：蟑螂、白蚁和螳螂）或纺足目（足丝蚁）关系密切。我们通过分析核18S rDNA序列推断缺翅目的系统发育位置，并根据二级结构模型进行比对。最大似然法和贝叶斯分析均支持缺翅目与蜚蠊目之间具有密切关系，且后验概率相对较高。缺翅目的18S序列表现出几个不寻常的特性：（1）替换率显著增加，导致分支非常长；（2）在螺旋E23处有长插入；（3）螺旋12和18处二级结构的修饰。
