Discoveries

April 23, 2024

Picking Sides

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Scientists recently discovered that a gene variant may play a role in determining if a person is a leftie or a rightie, the Smithsonian Magazine reported.

The prevailing research has attributed the determining factors to brain asymmetry, with left-handed individuals exhibiting dominance in the right hemisphere.

This asymmetry develops in the womb and manifests in various ways, but researchers haven’t clearly established the exact mechanisms – until now.

In their new study, a research team analyzed genetic data of around 350,000 people collected from the United Kingdom’s Biobank database.

Their sample was made up of more than 38,000 lefties and around 313,000 righties.

The team explained that past studies came across genes that influenced left-handedness, but they mainly focused on common genetic variants. The new analysis looked into rarer ones as well as variants coded for proteins.

Their findings showed that the TUBB4B variant was more common in left-handed people than in righties.

TUBB4B is present in less than one percent of people and is related to proteins that provide structures for the cells that are called tubulins. The latter are made up of filaments known as microtubules, which act like cells’ skeletons.

The study team and other researchers noted that these findings support the role of tubulins in determining the brain’s asymmetry, as well as how microtubules impact whether a person prefers to use their left or right hand.

Co-author Clyde Francks said the study can give clues about how genes affect the developmental mechanisms of brain asymmetry.

Even so, it could all come down to chance.

“We think that most instances of left-handedness occur simply due to random variation during development of the embryonic brain, without specific genetic or environmental influences,” Francks told Reuters.

This story originally appeared in the April 23, 2024 newsletter, Breeding Ground.