91 Oral - Neurobehavior I
Friday April 08, 11:15 AM - 11:30 AM

Authors:
Jeffrey Hatfield; Trudy Mackay; Robert Anholt

Affiliation: Clemson University, Center for Human Genetics, Greenwood, SC

Keywords:
k. feeding behavior; x. other (Substance abuse)

Studies on the genetic basis of susceptibility to cocaine addiction in human populations are quite challenging due to limited sample sizes, heterogeneity of genetic backgrounds, and environmental variability. Drosophila present a powerful model for investigation into the genetic underpinnings of cocaine addiction, using preference for cocaine as a proxy for addiction behavior. Utilizing the Microplate Feeder Assay (MFA), I quantified cocaine preference for 16,442 flies across 103 distinct genetic backgrounds of the Drosophila melanogaster Genetic Reference Panel (DGRP). I provided individual flies with an equal choice between 10µL of a control liquid food (4% sucrose, 1% yeast extract, and 0.004% FD&C Blue #1) and 10µL of the same liquid food supplemented with 0.02% cocaine. Solutions were delivered with the MFA, and consumption of each solution was quantified using a plate reader following a 22-hour exposure. Normalized cocaine preference was calculated for each fly as the difference in consumption between the two solutions divided by their total consumption. I found significant, naturally-occurring genetic variation for cocaine preference across this subset of the DGRP. I also observed significant sexual dimorphism across tested DGRP lines, where male flies on average exhibit higher cocaine preference than female flies of the same line. Overall, males of 18.4% of tested DGRP lines preferred cocaine-supplemented food over control food, while females of only 3.9% of lines preferred the cocaine solution. Estimates of broad sense heritability of consumption were calculated using individual level data, as well as using DGRP line means, and were found to be H² = 0.19 and H² = 0.97, respectively. Here, we demonstrate the impact of genetics on susceptibility to cocaine addiction behavior in D. melanogaster. These data will facilitate future genome-wide association analyses, as well as identify D. melanogaster genetic backgrounds from the DGRP that can better model cocaine addiction.