|Title:||Molecular Genetics of Aggressive Behaviour in Drosophila Melanogaster|
|Name:||Charalambos P. Kyriacou|
Department of Genetics
University of Leicester
Aggressive behaviour has been extensively studied, both in vertebrate and non-vertebrate model organisms. Remarkably, these studies indicate common elements that underlie socially mediated changes in behaviour. For example, chemical messengers such as serotonin have been implicated in aggression in mammals and crabs. It is rather surprising then, that the fruitfly, Drosophila, has not been used to explore the molecular genetics of aggression, despite the fact that this type of behaviour has been documented in flies. We have been attempting to find out which genes and proteins get 'turned on' in flies when they behave aggressively to each other.
As most of the aggressive interactions in fruitflies occur during defence of a resource such as food, territory, or a mate, we have studied male-male aggressive encounters on a patch of food. We have found that fruitfly males can be extremely aggressive with each other, or, at the other extreme, barely notice each other at all. As these flies are genetically identical, we can ask the question, "which genes have been turned on in the very aggressive flies, compared to those that are more "mellow" and non-aggressive?." To answer this question, we have made use of a relatively new technology called microarray analysis, which allows us to study the expression of all of the fly's 13,000 genes at once. Thus we take very aggressive and very "mellow" flies, mash up their heads, extract the working copy of every one of their genes, the RNA, and, using the microarray, measure which genes show relatively high or low levels of RNA in the two types of animals. In this way we obtain a gene profile of the aggressive and the non-aggressive flies. We can then take these candidate aggressive genes and, using various techniques, express them at high levels in a fly to see if it becomes more aggressive. We can even modify this procedure and overexpress these candidate "aggro" genes in specific regions of the brain, thereby mapping brain structures with behaviour. Because it appears that vertebrates and insects may share many of the genetic elements for aggression, our findings with the fruitfly model shall be of fundamental interest to those working on human aggression.