A novel approach in biological systematics: Phylogenetic analysis of Polyneoptera (Hexapoda, Insecta) based on neuropeptide sequences

神经肽是后生动物神经和激素系统中结构最多样的信使分子。由于神经肽及其特异性受体的相互依赖性，大多数氨基酸取代只有在各自的受体序列共同进化时才变得普遍。这种进化适应非常罕见。这就是为什么在神经肽中建立的氨基酸取代可以在遗传学上提供非常丰富的信息。使用MALDI-TOF质谱法，我们可以证明，来自单个昆虫的神经肽的广泛测序是快速和可重复的（高速物种分析）。在当前的项目中，我们扩展了这种质谱方法。感兴趣的焦点是神经肽数据在多大程度上适合于研究物种丰富的高等类群内六足类的系统发育关系。为此，我们将研究神经肽的Polyneoptera（昆虫纲），这仍然是有争议的系统发育讨论的主题，并分析最广泛的数据集上的神经肽以往任何时候都编译后生动物。该项目提案包括两个部分。第一个子项目的目标是质谱测序和神经肽序列的系统发育分析。这是我们第一次大规模地整合多个神经肽拷贝。在第二个子项目中，来自其他测序项目的当前数据集（e. G. 1 KITE，基因组计划）将被分析并用于神经肽基因的鉴定。将完成（克隆）神经肽基因的不完整EST序列，以确定多个神经肽拷贝在前体序列中的位置。这些实验对子项目1有直接影响，因为它们确保了远亲类群之间神经肽拷贝的正确对齐。我们的分类单元采样是由1 KITE项目的分类单元采样指导的;计划将自己的序列数据纳入其他组的数据集（总证据树）。预计第二子项目的数据将首次对具有多个肽拷贝的神经肽前体的演变和多样化进行非常详细的分析。

Neuropeptides are the structurally most diverse messenger molecules in the nervous and hormone system of Metazoa. Due to the interdependence of neuropeptides and their specific receptors, most amino acid substitutions become prevalent only if the respective receptor sequences co-evolve. Such evolutionary adaptations are very rare. This is why established amino acid substitutions in neuropeptides can be phylogenetically very informative. Using MALDI-TOF mass spectrometry, we could show that extensive sequencing of neuropeptides from single insects is fast and reproducible (High Speed Species Analysis). With the current project we extend this mass spectrometric approach. The focus of interest is to which extent neuropeptide data are suitable for studying the phylogenetic relationships of species-rich higher taxa within Hexapoda. For that purpose we will study neuropeptides of Polyneoptera (Insecta), which continue to be the subject of controversial phylogenetic discussion, and analyze the most extensive dataset on neuropeptides ever compiled for Metazoa. The project proposal contains two parts. The first subproject aims at mass spectrometric sequencing and the phylogenetic analyses of neuropeptide sequences. For the first time, we incorporate multiple neuropeptide copies on a large scale. In the second subproject, current datasets from other sequencing projects (e. g. 1KITE, genome projects) will be analyzed and used for the identification of of neuropeptide genes. Incomplete EST sequences of neuropeptide genes will be completed (cloned) to determine the position of multiple neuropeptide copies within the precursor sequences. These experiments have a direct impact on subproject 1 because they ensure a correct alignment of neuropeptide copies between distantly related taxa. Our taxon sampling is guided by the taxon sampling of the 1KITE project; the incorporation of own sequence data in data sets of other groups is planned (total evidence trees). It is also expected that data from the second subproject allow, for the first time, a very detailed analysis of the evolution and diversification of neuropeptide precursors with multiple peptide copies.