The vast majority of humanity uses their right hand to write, but around 10% are left-handed. A new study identified rare variants of a gene 2.7 times more common in left-handed people, the agency reported this Tuesday Reuters. The TUBB4B gene may play a role in the development of cerebral asymmetry underlying the determination of a dominant hand.
In most people, the two hemispheres of the brain are dominant for different functions and “the left hemisphere also controls the dominant right hand,” explained neurobiologist Clyde Francks, author of the study published in the journal Nature Communications.
“The relevant nerve fibers cross from left to right in the lower part of the brain. In left-handers, the right hemisphere controls the dominant hand. The question is: what causes brain asymmetry to develop differently in left-handers?” , he pointed out. TUBB4B controls a protein that integrates into filaments called microtubules, which provide the internal structure of cells. The identification of rare mutations in this gene, which are more common in left-handers, suggests that microtubules are involved in creating the brain’s normal asymmetries, Francks said.
The findings are based on genetic data from more than 350,000 adults in Great Britain.
The study also found evidence relevant to the field of psychiatry. People with schizophrenia are about twice as likely to be left-handed or ambidextrous and people with autism are about three times as likely, the neurobiologist said.
“Some of the genes that function in the developing brain during early life may be involved in both brain asymmetry and psychiatric features,” he noted.
