Aggression genes in fruit flies
Around eighty genes determine the aggressive behavior of the fruit fly Drosophila melanogaster, American geneticists have discovered through the targeted breeding of aggressive male flies.
Fruit flies are usually more peaceful with each other. Competing males will only bump into each other a little, and even more aggressive laboratory strains will lose their aggressive behavior after a few generations. This indicates that aggressive behavior is genetically controlled in flies.
See also the video under "Media", which shows two males arguing.
Herman Dierick and Ralph Greenspan of the Neurosciences Institute in San Diege now placed two Drosophila males each in a "battle arena" and from twenty of these encounters mated the more violent males with randomly selected females. The resulting sons were also sent into the arena.
After ten generations, the flies were already much more combative. After the 21st generation, males emerged that were over 30 times more aggressive than their normal counterparts.
Genetic analysis revealed alterations in about eighty genes in the battle-hardened males. In particular, a gene called Cyp6a20, which encodes the enzyme cytochrome P450, appears to have a significant influence on the aggressive behavior of fruit flies. Further studies should show how these genes influence the behavior of flies.
