Mutations in these genes lead to dramatic homeotic phenotypes, where one body part is replaced by another - for example, an antenna by a leg. We are studying how Hox genes control segment diversity in Drosophila, and how changes in the domains and details of Hox gene expression may have contributed to the bewildering diversity of body plans seen in different arthropods. We are also using the structure and organisation of the Hox gene cluster itself for molecular phylogenetic studies within arthropods. One particular interest is the relationship between insects, crustacea and myriapods - an area where molecular phylogenies based on rRNA appear to be in conflict with traditional views. Hox genes in brachiopods and priapulids and protostome evolution.
Most insects bear sensory organs, such as bristles, over the cuticle of the body.
In many insects the bristles are distributed randomly, but in others they are aligned into rows or organised into stereotyped spatial arrays. A single, highly derived, species of Dipteran, Drosophila melanogaster, has been the focus of investigation into the genetic control of the arrangement of sensory bristles. The achaete-scute genes encode transcriptional regulators bearing a bHLH motif whose expression endows cells with neural potential. We are addressing the question of how all of these different patterns are constructed. Our studies involve the isolation of homologues of the achaete-scute genes in various Dipteran and other insect species and a study of the conservation of the genetic mechanisms regulating their expression.