Comparative analysis of neurogenesis in the branchiopod Daphnia magna and the malacostracan Orchestia cavimana.

• Applicant: Dr. Petra Ungerer
• Subject Area: Evolutionary Cell and Developmental Biology (Zoology)
• Term: from 2008 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 73315376

The question of the internal relationships of arthropods including such diverse animals as insects, crustaceans, myriapods and chelicerates is still a matter of vivid debate. There is increasing evidence for a sister-group relationship of insects and crustaceans (Tetraconatahypothesis) contrasting the traditional Tracheata-hypothesis which favours a sister-group relationship of insects and myriapods. A particularly strong morphological argument for the Tetraconata is represented by the mode of neurogenesis via specialised neural progenitor cells – the neuroblasts - and a characteristic set of early differentiating neurons, so-called pioneer neurons, which establish the main axon pathways of the central nervous system. However, until today these neuroblasts and pioneer neurons have only been unambiguously identified in higher crustaceans (malacostracans) and it is not clear yet if these are also present in other major crustacean groups, such as branchiopods. As a series of recent phylogenetic analyses favour paraphyletic Crustacea with only one of its subgroups representing the sister-group to Hexapoda, it is important to fill the gap of knowledge concerning the crucial neural characters in non-malacostracan crustaceans. Therefore, early neurogenesis and axogenesis will be studied in detail in the branchiopod Daphnia magna by moleculargenetic and morphological methods including in-vivo single cell labelling. As moleculargenetic analyses of neurogenesis are largely missing in crustaceans until now, the higher crustacean Orchestia cavimana will be included in this part of the investigation. The data will allow for the first time for a comprehensive comparison of neurogenesis in the major euarthropod groups and result in the development of a scenario for the evolution of neural development in arthropods.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professorin Dr. Angelika Stollewerk