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Diversification of Neuromuscular Networks in Drosophila melanogaster
Every behaviour requires locomotor machinery to perform movement. In insects, the core unit of this machinery is a muscle and a neuron controlling its contraction. This unit is repeated, arranged into patterns and embedded into a neuromuscular network.
In the Central Nervous System, the development of this network starts with an array of neuronal stem cells that is identical in all segments. At the end of embryogenesis, however, segmental differences have formed among segments as adaptations to specific functions.
In this project, I investigate the mechanisms leading to this diversification and the cues underlying them. I address these questions in the different neuromuscular networks in the most posterior segments of A8 and A9 and compare them to the stereotypically repeated segments more anterior in the abdomen.
I demonstrate mechanisms leading to alterations specific for A8/9. These include the recruitment of a certain number of myoblasts; changes of the position of muscle progenitors; changes in the expression profile of markers for certain muscles; the development of specific dendrite morphologies; altered matches between neurons and their target muscles; and the death of supernumerary neurons. Finally, I show that many of these mechanisms are determined by the expression of the Hox gene Abdominal-B.
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