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

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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.