Department of Life Sciences Seminar
Pancrustacean phylogenomics and remipepede venomics
Bjoern M. von Reumont
Aquatic Invertebrates, Dept.of Life Sciences, NHM
Wednesday 27 of February 11:00
Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)
Remipedes are a small and enigmatic group of crustaceans, first described only 30 years ago. The stygiobiontic species of this group dwell in remote underwater cave habitats, so called anchialine caves. New analyses of both morphological and molecular data have recently suggested a close relationship between Remipedia and Hexapoda instead of the former hypotheses that remipedes represent a rather basal split within crustaceans. Thus, remipedes may be pivotal for understanding the evolutionary history of crustaceans and hexapods. However, to test this hypothesis using new data and new types of analytical approaches from the field of NGS (Next Generation Sequencing) data is important. The most recent phylogenomic analysis of pancrustaceans includes all crustacean species for which EST data are available (46 species), and the largest alignment encompasses 866,479 amino acid positions and 1,886 genes. A series of phylogenomic analyses was performed to evaluate pancrustacean relationships. The results demonstrate that the different ways to compile an initial data set of core orthologs and the selection of data subsets by matrix reduction can have marked effects on the reconstructed phylogenetic trees. Further, the comparison of nucleotide vs aminoa acid data level might represent an important step to identify noise and misleading signal in the data. Venomous animals are ubiquitous in aquatic and terrestrial habitats across the world. However, our understanding of fundamental issues about the biology and evolution of venoms and venomous organisms is incomplete because the main empirical pillars of venomics - the scientific study of venoms – are currently limited to a few well-studied taxa such as spiders, scorpions, reptiles and cone snails. In order to broaden and strengthen the foundation of venomics, a renewed focus on neglected putatively venomous taxa is needed, especially on taxa that are distantly related to known venomous species. In this respect aquatic cave dwelling remipede crustaceans are an extraordinarily promising group, as Crustacea is the only major traditional arthropod group that lacks known venomous species. We present here the first 3D morphological reconstruction of the venom apparatus of remipedes, as well as a transcriptomic profile of genes expressed in their putative venom glands based on next generation sequencing. The results shed new light on the convergent recruitment of venom toxins in the animal kingdom.
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