Vertebrate Homologs of the Neurogenic Genes of Drosophila

This chapter discusses the vertebrate homologs of the neurogenic genes of Drosophila. Many genes involved in the control of important developmental events in Drosophila are conserved in vertebrates, and the isolation and characterization of these genes has been a valuable addition to the approaches available for the study of vertebrate development. The first homologs analyzed in such a fashion are the vertebrate homeobox containing Hox genes. The neurogenic loci of Drosophila melanogaster consist of a group of genes implicated in the proper segregation of epidermal and neural progenitor cells during formation of both the central and peripheral nervous systems. In the Drosophila embryo, the central nervous system originates from the ventrolateral neurogenic region of the ectoderm. Progenitor cells in this region give rise to two types of differentiated cells: neuroblasts that delaminate from the epithelial layer and divide to produce the neurons of the brain and ventral nerve cord and epidermoblasts that remain in the epithelial layer and give rise to ventral epidermis and secrete the embryonic cuticle.