The study, published in Nature Communications, found that when offered the choice between water and diluted alcohol, 'normal' mice drank water. However, mice with a mutation in the Gabrb1 gene drank from the bottle of alcohol 85 percent of the time.
The mice with the gene mutation worked harder than other mice to get at the alcohol - about the strength of wine - by pushing a lever. They continued to work for longer than the other mice until they had consumed so much alcohol that they had difficulties in coordinating their movements.
Dr Quentin Anstee, consultant hepatologist at Newcastle University and joint lead author, said: 'It's amazing to think that a small change in the code for just one gene can have such profound effects on complex behaviours like alcohol consumption'.
Gabrb1 codes for a component of a protein receptor present in a region of the brain that controls pleasurable emotions and reward, the nucleus accumbens. The receptor responds to a neurotransmitter called GABA, a chemical that carries messages between brain cells. The researchers found that the gene mutation caused the receptor to act as if it was constantly stimulated, even in the absence of GABA.
The researchers say that a similar mechanism is present in humans and this study could help to identify those most at risk of developing an addiction and ensure they receive the most effective treatment.
Professor Hugh Perry, chair of the MRC's Neurosciences and Mental Health Board, said: 'Alcohol addiction places a huge burden on the individual, their family and wider society. There's still a great deal we don't understand about how and why consumption progresses into addiction, but the results of this long-running project suggest that, in some individuals, there may be a genetic component'.