Left-handedness: Gene discovered

Scientists have discovered the first gene which appears to increase the odds of being left-handed. The Oxford University-led team believes carrying the gene may also slightly raise the risk of developing psychotic mental illness such as schizophrenia. The gene, LRRTM1, appears to play a key role in controlling which parts of the brain take control of specific functions, such as speech and emotion.

The study appears in the journal Molecular Psychiatry. The brain is set up in an asymmetrical way. In right-handed people the left side of the brain controls speech and language, and the right side controls emotions.

However, in left-handed people the opposite is true, and the researchers believe the LRRTM1 gene is responsible for this flip. They also believe people with the LRRTM1 gene may have a raised risk of schizophrenia, a condition often linked to unusual balances of brain function.

Further research

Lead researcher Dr Clyde Francks, from Oxford University's Wellcome Trust Centre for Human Genetics, said the next step would be to probe the impact on the development of the brain further. He said: "We hope this study's findings will help us understand the development of asymmetry in the brain.

"Asymmetry is a fundamental feature of the human brain that is disrupted in many psychiatric conditions." However, Dr Francks said left-handed people should not be worried by the links between handedness and schizophrenia. He said: "There are many factors which make individuals more likely to develop schizophrenia and the vast majority of left-handers will never develop a problem. "We don't yet know the precise role of this gene."

About 10% of people are left-handed

There is evidence to suggest there are some significant differences between left and right-handed people. Australian research published last year found left-handed people can think quicker when carrying out tasks such as playing computer games or playing sport. And French researchers concluded that being left-handed could be an advantage in hand-to-hand combat. However, being left-handed has also been linked to a greater risk of some diseases, and to having an accident. - BBC News