Right-handers make up to 90% of the entire population, while only about 10% of people are left-hand dominant. Scientists have used ultrasound to determine that the predisposition towards right-handedness or left-handedness can be predicted as early as in the womb.
Clyde Francks from the Max Planck Institute for Psycholinguistics in the Netherlands explains, ‘There is a strong tendency towards right-handedness encoded in the human genome, but it is not absolute.’
‘The decision’ regarding which hand will be dominant is thought to occur quite randomly, early in the embryonic stage. Individuals with a rare variant of a specific gene have a significantly higher likelihood of being left-handed.
The study focuses on the relationship between rare genetic variants and left-handedness, and it highlights the complexity of human genetics and brain development.
We looked at approximately 350,000 people and searched for these rare genetic variations that correlate with left-handedness. We found a specific gene, TUBB4B, where rare disruptive genetic variants occur more frequently in left-handers than in right-handers,’ detailed Clyde Francks.
And this suggests that the TUBB4B gene codes for a protein involved in the asymmetric development of the brain, that is, how the left and right sides of the brain develop slightly differently,’ he clarified.
Disruptive genetic variants are found in less than one percent of the global population, yet they are 2.7 times more likely to occur in left-handers than in right-handers. Even today, many people suppress left-hand dominance due to pressure during childhood from families or educational systems.
