Roth Steffen, Fromm Bastian, Gäde Gerd, Predel Reinhard
Institute of Zoology, University of Jena, Erbertstrasse, Germany.
BMC Evol Biol. 2009 Mar 3;9:50. doi: 10.1186/1471-2148-9-50.
Neuropeptide ligands have to fit exactly into their respective receptors and thus the evolution of the coding regions of their genes is constrained and may be strongly conserved. As such, they may be suitable for the reconstruction of phylogenetic relationships within higher taxa. CAPA peptides of major lineages of cockroaches (Blaberidae, Blattellidae, Blattidae, Polyphagidae, Cryptocercidae) and of the termite Mastotermes darwiniensis were chosen to test the above hypothesis. The phylogenetic relationships within various groups of the taxon Dictyoptera (praying mantids, termites and cockroaches) are still highly disputed.
Tandem mass spectrometry of neuropeptides from perisympathetic organs was used to obtain sequence data of CAPA peptides from single specimens; the data were analysed by Maximum Parsimony and Bayesian Interference. The resulting cladograms, taking 61 species into account, show a topology which is in general agreement with recent molecular and morphological phylogenetic analyses, including the recent phylogenetic arrangement placing termites within the cockroaches. When sequence data sets from other neuropeptides, viz. adipokinetic hormones and sulfakinins, were included, the general topology of the cladogram did not change but bootstrap values increased considerably.
This study represents the first comprehensive survey of neuropeptides of insects for solely phylogenetic purposes and concludes that sequences of short neuropeptides are suitable to complement molecular biological and morphological data for the reconstruction of phylogenetic relationships.
神经肽配体必须精确地与其各自的受体相匹配，因此其基因编码区的进化受到限制，可能高度保守。因此，它们可能适合用于重建高等分类单元内的系统发育关系。选择蟑螂主要类群（蜚蠊科、姬蠊科、蜚蠊科、多食亚目、隐尾蠊科）以及白蚁达尔文澳白蚁的CAPA肽来检验上述假设。昆虫纲（螳螂、白蚁和蟑螂）各群体内部的系统发育关系仍存在很大争议。
利用来自交感神经周围器官的神经肽串联质谱法获取单个标本的CAPA肽序列数据；通过最大简约法和贝叶斯推断对数据进行分析。由此得到的系统发育树考虑了61个物种，其拓扑结构总体上与最近的分子和形态系统发育分析一致，包括最近将白蚁置于蟑螂中的系统发育排列。当纳入来自其他神经肽（即促脂动激素和速激肽）的序列数据集时，系统发育树的总体拓扑结构没有变化，但自展值显著增加。
本研究是首次仅出于系统发育目的对昆虫神经肽进行的全面调查，并得出结论，短神经肽序列适合补充分子生物学和形态学数据以重建系统发育关系。
