Scientists have discovered a gene, which they’ve named the “hangover” gene, that controls alcohol tolerance and time to recover from exposure to alcohol.

Ulrike Heberlein at the University of California at San Francisco, US, and Henrike Scholz from the University of Würzburg in Germany, exposed fruit flies to ethanol vapour. Intoxicated fruit flies show similar behaviour to tipsy humans: they lack coordination and postural control and then fall asleep. It took the flies an average of 20 minutes to recover following their exposure.

After four hours on the wagon, the same Drosophila were again exposed to alcohol. By now, they had developed a tolerance to alcohol and so needed more to reach the same drunkenness, and took longer to “dry out” — 28 minutes.

But flies with a defective form of the hangover gene still took 20 minutes to recover from inebriation time after time – never building up a tolerance. — New Scientist

Some defect.

The study also found that fruit flies under stress had a higher tolerance to alcohol, and took longer to recover — but only with the hangover gene.