Campbell B C, Steffen-Campbell J D, Gill R J
WRRC, USDA-ARS, Albany, California 94710-1100.
Insect Mol Biol. 1994 May;3(2):73-88. doi: 10.1111/j.1365-2583.1994.tb00154.x.
Phylogenetic analysis of 18S rDNA nucleotide sequences of hemipteran exemplars shows Sternorrhyncha (psyllids, whiteflies, aphids and scales) is monophyletic and forms a sister group to all other hemipterans (Euhemiptera). Whiteflies form a sister group to all other Sternorrhyncha. Primary structures of 18S rDNAs of all sternorrhynchans are exceptionally long (approximately 2200 to approximately 2500 bp) due to internal expansions. These expansions are a synapomorphy of Sternorrhyncha; other hemipterans possess shorter 18S rDNAs (approximately 1900 to approximately 1925 bp). The 18S rDNA of whiteflies is the longest recorded to date and has a base substitution rate of approximately 3 times greater than Euhemiptera taxa examined. The relevance of these findings to the fossil record, feeding strategies, reproductive biologies, and geoclimatic distribution is discussed.
半翅目典型样本的18S rDNA核苷酸序列的系统发育分析表明，胸喙亚目（木虱、粉虱、蚜虫和介壳虫）是单系的，并且形成了所有其他半翅目（真半翅亚目）的姐妹群。粉虱形成了所有其他胸喙亚目的姐妹群。由于内部扩张，所有胸喙亚目的18S rDNA的一级结构异常长（约2200至约2500 bp）。这些扩张是胸喙亚目的一个共衍征；其他半翅目拥有较短的18S rDNA（约1900至约1925 bp）。粉虱的18S rDNA是迄今为止记录到的最长的，其碱基替换率比所研究的真半翅亚目类群大约高3倍。讨论了这些发现与化石记录、取食策略、生殖生物学和地球气候分布的相关性。
