According to a groundbreaking new study from neurology journal Brain, research into the correlation between handedness, language areas of the brain and neuropsychiatric diseases has finally proved that genetics played a role in left-handedness.

By analysing the genomes of about 400,000 people from the U.K. Biobank, scientists from the University of Oxford were able to pinpoint four regions of DNA that determined left-handedness.

Through scanning the brains of the participants, researchers discovered mutations in the “scaffolding” inside the body’s cells, called the crytoskeleton, that changed the structure of the white matter of the brain.

“Many animals show left-right asymmetry in their development, such as snail shells coiling to the left or right, and this is driven by genes for cell scaffolding, what we call the ‘cytoskeleton’,” explained Professor Gwenaëlle Douaud, from the Wellcome Centre for Integrative Neuroimaging at the University of Oxford.

“For the first time in humans, we have been able to establish that these handedness-associated cytoskeletal differences are actually visible in the brain.

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