New York, March 25 (IANS): Researchers from the Virginia Commonwealth University have discovered a biological clue that could help explain why some drinkers develop a dependence on alcohol while others do not.

The findings move researchers closer to identifying those at risk for addiction early and designing better drug treatments to help people stop drinking.

"If we can better understand the molecular effects of alcohol, we can design more rational treatments and even warn people who are more susceptible to developing a dependence," said Jill C. Bettinger, associate professor in the department of pharmacology and toxicology in a paper published in the journal Proceedings of the National Academy of Sciences.

The paper describes how researchers examined the role of a protein complex -- called switching defective/sucrose non-fermenting (SWI/SNF) -- in determining the behavioural response of roundworms to alcohol.

Humans and worms have a similar genetic makeup.

Bettinger and associate professor P. Riley Brien found that naturally occurring genetic variations in the same SWI/SNF complex so crucial to a worm's tolerance were also associated with alcohol dependence in humans.

The evidence suggests that the likelihood to develop alcoholism is the product of mutations in many genes, each with small effect.

"The identification of genes that are critical in the development of tolerance in model systems such as worms will lead to future progress in understanding human dependence on alcohol," Riley concluded.

If the same effects are seen in worms, then it allows us to form and test a functional hypothesis about what kinds of changes lead to increased dependence risk in humans, the authors concluded.