We are not surprised to find that aggression is a trait that is easily bred in animals. Spanish fighting bulls and pit bulls are the end result of careful selection of the most aggressive members of their species. Back in 1983, Lagerspetz and Lagerspetz bred the most aggressive mice in each generation to each other, and after 25 generations, produced mice that would instantly attack any other mouse in their vicinity.
Herman Diereck and Ralph Greenspan want to discover the genetic correlates of aggression. Instead of tackling the complex genome of mammals, they decided to breed fighting fruit flies. Apparently, fruit flies in the wild are naturally quite territorial and aggressive, but quickly become domesticated in the laboratory. By selecting the most aggressive flies for mating, Diereck and Greenspan noticed a difference in as little as five generations. After 21 generations, aggressiveness had increased 30-fold.
Out of the approximately 14,000 genes in the fruit fly genome, about 80 seemed to be different in the aggressive flies relative to their more passive friends. Two of these, both relating to the flies’ reactions to pheromones, appear particularly promising as candidates for influencing the enhanced aggressiveness of the flies.
You can see a video of the fighting flies here. Okay, so it’s not Mike Tyson, but the little guys put up quite a fight.
References:
[1] Lagerspetz, K. M. J., & Lagerspetz, K. Y. H. (1983). Genes and aggression. In E. C. Simmel, M. E. Hahn, & J. K. Walters (Eds.), Aggressive behavior: Genetic and neural approaches (pp. 89-102). Hillsdale, NJ: Erlbaum.
[2] Diereck, H.A., & Greenspan, R.J. (2006). Molecular analysis of flies selected for aggressive behavior. Nature Genetics, 38, 1023-1031.
3 Comments
cableguy · October 15, 2006 at 12:51 pm
What an interesting video. I have to say though, I can’t blame the fly…I’m the same way when someone tries to get my pudding too!
nelsayed · November 26, 2006 at 4:28 pm
I think it’s so interesting that flies and other animals can be selectively bread to produce aggressive offspring. It makes you think about just how much of your personality you inherit from your parents.
triciagordon3213 · December 5, 2006 at 10:12 pm
I think it’s amazing that a fruit fly can have such complex charcteristics as aggression. I though flies were just simple little bugs, but I guess their is a lot more too them than that. I definitley didn’t think they could have personality characteristics like being aggressive. I thought all flies were the same, just little clones of eachother; I had no idea they could have such huge differences.
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