Edward Kravitz, Ph.D.

George Packer Berry Professor of Neurobiology

Harvard Medical School
Dept of Neurobiology
220 Longwood Ave
Boston, MA 02115
Telephone: 617-432-1753
Fax: 617- 734-7557
Email: edward_kravitz@hms.harvard.edu
Predocs: 0 Postdocs: 6 Completed PhD's: 7

GENETIC MANIPULATIONS IN THE FRUIT FLY FIGHT CLUB: Aggression is a nearly universal feature of the behavior of social animals. In the wild, it is used for access to food and shelter, for protection from predation and for selection of mates, all of which are essential for survival. Despite its importance, little is known of the neural mechanisms that underlie aggressive behavior, other than that hormonal substances including amines, peptides and steroid hormones serve important roles in the behavior.

Our laboratory examines aggression using common strains of the fruit fly, Drosophila melanogaster. Although not widely known, male and female fruit flies do fight and males at least become territorial (establish dominance relationships). With the genome fully sequenced and with elegant methods available for the selective manipulation of genes in subsets of central nervous system neurons, behavioral studies of aggression in flies offer a powerful new experimental system for identifying the fundamental mechanisms underlying this behavior. Using a simplified experimental system we have carried out a quantitative analyses of fighting behavior in male and female flies (see labworks.hms.harvard.edu PNAS 2002 and 2004).

With these in hand we have begun the following experiments:

1. We are using the GAL4/UAS system to alter amine neuron function in fly brains while flies are fighting.
2. we are examining genes of the sex-determination hierarchy in male- and female-specific patterns of aggression.
3. We are examining the learning and memory associated with winning and losing fights in male flies
4. We are examining the roles of peptides in aggression.

Among our recent findings are:

1. That the fruitless gene that specifies whether flies court males or females also specifies whether flies fight like males or females
2. That flies alter their fighting strategies after a hierarchical relationship is established
3. That losing flies remember the outcomes of fights for at least 30 minutes and can recognize previous opponents
4. That there is a dramatic reduction in aggression when dopamine and serotonin neurons are turned off during fights.

References:

• Yurkovic A, Wang O, Basu AC and Kravitz EA (2006) Learning and memory associated with aggression in Drosophila melanogaster. Proc. Nat. Acad. Sci. 103: 17519-17524.
• Vrontou E, Nilsen S, Demir E, Kravitz EA and Dickson BJ (2006) fruitless regulates aggression and dominance in Drosophila. Nature Neuroscience. 9: 1469-1471.
• Chen S, Lee AY, Bowens N, Huber R and Kravitz EA (2002) Fighting fruit flies: a model system for the study of aggression. Proc. Natl. Acad. Sci. 99: 5664-5668.
• Kravitz EA (2000) Serotonin and aggression: insights gained from a lobster model system and speculations on the role of amine neurons in a complex behavior like aggression. J. Comp. Physiol. A. 186: 221-238.