As in vertebrates, the neuroendocrine system consists of neurosecretory cells located in the brain which produce hormones as wells as associated hemal glands which store and release these hormones. For vertebrates, the neurosecretory cells are located in the hypothalamus and are associated with the pituitary. In Drosophila, neurosecretory cells are located in the medial protocerebrum and partner with the hemal ring gland, which surrounds the aorta.
The identification of particular regulatory genes controling the development of similar developmental pathways in Drosophila and vertebrates has been widely interpreted as signifying functional homology. It is clear that the last common ancestor (LCA) between fruit flies and humans possesed these genes; however, what context these genes had in the developmental pathways of the LCA is not known. Current evolutionary thinking suggests that the common ancestor is similar to the modern flatworm. In order to address the role of common regulatory genes directly, we are generating tools that allow us to study the (wildtype, but eventually mutant) development of a flatworm identified as closely resembling the LCA. Neochildea EST List
The brain of Drosophila develops during embryonic, larval and pupal periods. Approximately 80-100 neural stem-cells, called neuroblasts, form in the early embryo and generate neurons which, by the end of embryogenesis, allow for a functional motile larvae. These neural stem-cells continue to proliferate during both larval and pupal stages to generate the complex nervous system required for an adult fly to navigate through its environment. As in vertebrates, the Drosophila nervous system is highly compartmentalized both in structure and in function. We are creating an anatomical nomenclature of the larval and pupal central brain that we will eventually consolidate with existing and emerging embryonic and adult naming schemes.
One of the uses of digital models is as three-dimensional archives of function, pathology and gene/protein expression patterns. The idea, advertised and instituted for human (Strachan et al., 1997; Kerwin et al., 2004) and a number of genetic model systems (e.g., Baldock and Davidson, 1999; Carson et al., 2002; Baldock et al., 2003; Visel et al.,2004), is to transfer a digital representation of the expression patterns of genes in a given structure (and at a given stage) into an atlas model of that structure.