Carreno R A, Barta J R
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada.
J Med Entomol. 1998 Nov;35(6):1002-6. doi: 10.1093/jmedent/35.6.1002.
The small subunit ribosomal RNA (SSU rRNA) genes of hippoboscid (Ornithoica vicina Walker) and tabanid (Chrysops niger Macquart) Diptera were sequenced to determine their phylogenetic position within the order and to determine whether or not extensive hypervariable regions in this gene are widespread in the Diptera. A parsimony analysis of an alignment containing 8 dipteran sequences produced a single most parsimonious tree that placed O. vicina as sister group to Drosophila melanogaster Meigen. The tabanid Chrysops niger was sister group to the asilomorphan taxa, and the sister group to the Brachycera was a Tipula sp. although this relationship was not supported by bootstrap analysis. The hippoboscid and tabanid sequences contain extensive hypervariable regions in the V2, V4, V6, and V7 regions as do other Diptera. When these regions of the alignment were excluded from the phylogenetic analysis, a single most parsimonious tree was found. This tree had an identical overall topology to the tree obtained from the total data set. The hypervariable regions in parts of the dipteran SSU rRNA genes were more extensive in the nematocerous dipteran sequences used in this study than in the other dipteran representatives; these hypervariable regions may be of more utility in inferring relationship among species and subspecies than at the suprageneric level.
对虱蝇（Ornithoica vicina Walker）和虻（Chrysops niger Macquart）这两种双翅目昆虫的小亚基核糖体RNA（SSU rRNA）基因进行测序，以确定它们在双翅目内的系统发育位置，并确定该基因中广泛存在的高变区在双翅目中是否普遍存在。对包含8个双翅目序列的比对进行简约分析，得到了一棵单一的最简约树，该树将O. vicina置于黑腹果蝇（Drosophila melanogaster Meigen）的姐妹群位置。虻类的Chrysops niger是食虫虻类分类单元的姐妹群，而短角亚目的姐妹群是一种大蚊（Tipula sp.），不过这种关系未得到自展分析的支持。虱蝇和虻的序列在V2、V4、V6和V7区域含有广泛的高变区，其他双翅目昆虫也是如此。当在系统发育分析中排除比对的这些区域时，发现了一棵单一的最简约树。这棵树的总体拓扑结构与从总数据集获得的树相同。在本研究中使用的线虫类双翅目序列中，双翅目SSU rRNA基因部分区域的高变区比其他双翅目代表物种的更广泛；这些高变区在推断物种和亚种间的关系方面可能比在超属水平上更有用。
