'Hangover' gene in flies may assist alcoholism research

A gene discovered in fruit flies may help researchers understand the genetic basis of alcoholism in humans. Scientists at the University of California in San Francisco (UCSF) and the University of Wurzburg in Germany have found a gene that helps fruit flies tolerate alcohol. If a similar gene exists in humans, it could help to explain why the more some people drink, the higher their tolerance becomes, as well as why alcoholism tends to run in families.

In their study, the researchers compared normal flies with those that had a mutatedversion of a gene they named 'Hangover 1'. They put both types of flies into a column containing several platforms. When the flies were exposed to ethanol vapour, they exhibited similar characteristics to a human getting drunk: hyperactivity, increased lack of co-ordination and sedation. These effects caused them to fall from one platform to the next until they hit the bottom. The less tolerant the fly was to the vapour the faster it hit the bottom of the column.

At the first exposure to the ethanol vapour, the flies reached the bottom of the column in about 20 minutes. After a second shot, the flies took longer to reach the bottom. However, normal flies reached the bottom in 28 minutes, whereas mutant flies hit at 23 minutes, suggesting that the mutant flies may not acquire as great a tolerance to the vapour.

'Repeated alcohol consumption leads to the development of tolerance...This tolerance allows increased alcohol consumption that, over time, leads to physical dependence and possibly addiction', said Dr Ulrike Heberlein of UCSF and an author of the paper published in this week's Nature.

Further studies are needed to see if these findings apply only to alcohol exposure or if the gene plays a more general role in the fly's response to other stresses too, such as excessive heat.

The researchers hope that this information may be useful in studies on the part genes play in alcohol dependency and substance abuse in humans.