Left-handers have different brains, scientists discover

Scientists discover the genes linked to left-handedness and reveal that lefties have an advantage.

Researchers found four areas that seemed to be significantly different among left-handers. Picture: istock

Regions of the genes that make people more likely to be left-handed have been found by scientists, and for the first time they have been linked to changes in brain architecture.

Researchers said this may provide clues to how the trait of “handedness” develops. About 10 per cent of the population is left-handed and studies in twins suggest that roughly 25 per cent of the trait is genetic while the rest is down to the environment — including the environment in the womb.

By looking at the genomes of 400,000 Britons, of whom 38,000 were left-handed, researchers found four areas that seemed to be significantly different among left-handers. Three of these were associated with brain development, and brain imaging showed that they appeared to alter white matter and the scaffolding that joined regions associated with language. Akira Wiberg, from the University of Oxford, was an author on the paper, published in the journal Brain. He said that this finding pointed to an exciting area for further investigation. “We discovered that in left-handed participants the language areas of the left and right sides of the brain communicate with each other in a more co-ordinated way,” he said.

“This raises the intriguing possibility for future research that left-handers might have an advantage when it comes to performing verbal tasks, but it must be remembered that these differences were only seen as averages over very large numbers of people and not all left-handers will be similar.”

The research has identified only a small proportion of the genetic component of handedness. But Dominic Furniss, a co-author also from Oxford University, said it may go some way to redress the historical suspicion of lefties. “Left-handedness has been considered unlucky, or even malicious,” he said. “This is reflected in the words for left and right in many languages. In English ‘right’ also means correct or proper; in French ‘gauche’ means both left and clumsy. We have demonstrated that left-handedness is a consequence of the developmental biology of the brain, in part driven by the complex interplay of many genes. It is part of the rich tapestry of what makes us human”.

The Times