defined as the area under the curve from 2 to 25 minutes as determined by trapezoidal summation, and ΔDist is Distexposure2 – Distexposure1. Peak speed (PS) is the greatest speed achieved from 2 to 25 minutes. Sedation sensitivity (Sed) was quantified as the fraction of flies that lost the ability to right themselves following 26 minutes of ethanol exposure. Sedation tolerance (Sed Tol) is Sedexposure1 – Sedexposure2; n is the number of groups of flies tested, where groups are 20 to 25 genotypically identical male flies. Ethanol absorption was measured by exposing groups of 25 flies in the booz-o-mat locomotor tracking device to either ethanol vapor (47%) or humidified air for 15 minutes. Flies were frozen on dry ice immediately and the ethanol concentration in whole fly homogenates was measured with an alcohol dehydrogenase-based spectrophotometric assay (Diagnostic Chemicals, Ltd., Charlottetown, PE, Canada). Statistical analyses were carried out with Minitab 15.1.30.0 (State College, PA), and various derivative measures were calculated in Microsoft (Redmond, WA) Excel 2003. All error bars are standard error of the mean, except standard deviation for quantitative polymerase chain reaction (PCR).
