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Excerpts from:
Why are people born left-handed? Study suggests dominant hand is down to your genes
- About 10 per cent of the population is left-handed, and struggle with things right-handed people take for granted
- Recent research has identified genetic variants that separate left-handed people from right-handers, and may make lefties’ brains superior at verbal tasks
Published: 8:00pm, 29 Jan, 2020
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About 10 per cent of the population is left-handed (famous “lefties” include Bill Gate, Barack Obama, Lady Gaga, Kurt Cobain, David Bowie and Jimi Hendrix).
Most right-handed people are oblivious to the challenges of left-handedness, which go beyond the “right-left” elbow war and the problem of the left arm smudging one’s writing.
Lefties also struggle with some everyday items that can be found in the home and office: scissors, knives, measuring cups, vegetable peelers, measuring tapes, can openers – the list goes on. They also encounter awkward moments when faced with a simple handshake, while acts from swiping a credit card to doing up a zip can be problematic.
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Most research on this topic suggests left-handedness is a combination of genetics, biology and the environment.
A study published in 2019 in the journal Brain shed substantial light on the subject.
Conducted by a team of scientists at Britain’s University of Oxford, the study is the first to identify which genetic variants separate left-handed people from right-handers.
It identified genes linked with left-handedness that result in differences in brain structure, particularly the parts involved in language.
The team of researchers tapped the UK Biobank – a database of about 400,000 volunteers from across the country who had the full sequence of their genetic code recorded. About 38,300 were left-handed.
Dr Akira Wiberg, a medical research council fellow at the University of Oxford, who carried out the analyses, said: “Around 90 per cent of people are right-handed, and this has been the case for at least 10,000 years. Many researchers have studied the biological basis of handedness, but using large data sets from UK Biobank has allowed us to shed considerably more light on the processes leading to left-handedness.
“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 coordinated way. 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 study also found links between the genetic regions involved in left-handedness, very slightly higher risks of schizophrenia, and slightly lower risks of Parkinson’s disease.
The researchers emphasised: “These links only correspond to a very small difference in the actual number of people with these diseases, and are correlational, so they do not show cause and effect.”
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