Research

Phenotypic and transcriptional response to selection for alcohol sensitivity in Drosophila melanogaster

Tatiana V Morozova^1,2,3 , Robert RH Anholt^1,2,4 and Trudy FC Mackay^2,4

¹Department of Zoology, North Carolina State University, Raleigh, NC 27695, USA

²WM Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695, USA

³Institute of Molecular Genetics RAS, Kurchatov Square, Moscow 123182, Russia

⁴Department of Genetics, North Carolina State University, Raleigh, NC 27695, USA

author email corresponding author email

Genome Biology 2007, 8:R231doi:10.1186/gb-2007-8-10-r231

Published:	31 October 2007

Subject areas: Genetics, Physiology, Model organisms

Abstract

Background

Alcoholism is a complex disorder determined by interactions between genetic and environmental risk factors. Drosophila represents a powerful model system to dissect the genetic architecture of alcohol sensitivity, as large numbers of flies can readily be reared in defined genetic backgrounds and under controlled environmental conditions. Furthermore, flies exposed to ethanol undergo physiological and behavioral changes that resemble human alcohol intoxication, including loss of postural control, sedation, and development of tolerance.

Results

We performed artificial selection for alcohol sensitivity for 35 generations and created duplicate selection lines that are either highly sensitive or resistant to ethanol exposure along with unselected control lines. We used whole genome expression analysis to identify 1,678 probe sets with different expression levels between the divergent lines, pooled across replicates, at a false discovery rate of q < 0.001. We assessed to what extent genes with altered transcriptional regulation might be causally associated with ethanol sensitivity by measuring alcohol sensitivity of 37 co-isogenic P-element insertional mutations in 35 candidate genes, and found that 32 of these mutants differed in sensitivity to ethanol exposure from their co-isogenic controls. Furthermore, 23 of these novel genes have human orthologues.

Conclusion

Combining whole genome expression profiling with selection for genetically divergent lines is an effective approach for identifying candidate genes that affect complex traits, such as alcohol sensitivity. Because of evolutionary conservation of function, it is likely that human orthologues of genes affecting alcohol sensitivity in Drosophila may contribute to alcohol-associated phenotypes in humans.