BIO

Hi, my name is Taylor and I am a sophomore here at FSU. I am originally from Sarasota, Florida. The past two years I have been a biological science major but I just recently changed to psychology. I am still very interested in biology research and hope to continue on during my undergraduate years. I am particularly interested in behavior and genetics.

Exploring the relationship between melanic coloration and aggression in Drosophila melanogaster.

Abstract

Adaptive constraints, limitations that influence the outcome of genes, have important connections with the evolution of organisms as well as inheritance of complex traits. Pleiotropic effects are a classic example of an adaptive constraint. Pleiotropy occurs when one gene affects two or more unrelated traits. Here, we looked at melanic coloration and aggressive behavior in Drosophila melanogaster. Melanin production is thought to have an inhibitory effect on the neurotransmitter, dopamine, which can influence aggressiveness. Therefore, we hypothesized that pleiotropic effects cause a correlation between these two traits. Specifically, we predicted darker pigmentation would be positively associated with a higher degree of aggression. To test this, we quantified aggressive behaviors (fencing, boxing, and lunging) and artificially selected for high aggression, low aggression, and no selection (control) for 14 generations. We then measured the pigment of the dorsal thorax (trident) using ImageJ. Thus far, we found that generation 14, which was a more aggressive generation, was significantly darker than generation 3 when using an ANOVA. These results demonstrate a clear relationship between the level of aggression and melanin in D. melanogaster and provides some support for our hypothesis that pleiotropic effects are working on the two traits. However, more research is necessary to substantiate this, tests for the reverse effects, and to discover the genes that are behind this pleiotropic relationship. This research will further our understanding of adaptive constraints and how they affect the evolution of an organism’s traits.

Keywords: Drosophila, aggression, melanin, pleiotropy