Acetic acid and ethanol resistance of flies with a third chromosome from Austria or Cameroon in a genetic background lacking ADH activity. Acetic acid (275 μl of 40%): region, P<0.0001; sex, P=0.04; interaction, P=0.09. Ethanol (125 μl of 20%): region, P>0.9; sex, P=0.005; interaction, P>0.8.