Washington: What do Lady Gaga, Barack Obama, Bill Gates, Paul McCartney and Justin Bieber have in common with Jimi Hendrix, Judy Garland and David Bowie? They are all left-handed, a trait shared by about 10 percent of people.
But why are some people left-wing and the most right? It’s an area of active research, and new research has revealed a genetic makeup of left-handedness in some people. Researchers have identified a rare variant of a gene involved in controlling cell shape and found that it is 2.7 times more common in left-handed people.
Although this genetic variant affects only a small part of the left hand, perhaps 0.1 pc, researchers suggest that this gene, called TUBB4B, may play a role in the development of brain asymmetry. dominant hand.
In most people, the two hemispheres or hemispheres of the brain have slightly different anatomy and dominate different functions.
“For example, most people are left-hemisphere dominant for language and right-hemisphere dominant for tasks that require visual attention directed to a location in space,” said Clyde Franks, a neurobiologist at the Max Planck Institute.
Psycholinguistics in the Netherlands, the senior author of the study published Tuesday in the journal Nature Communications.
“In most people, the left hemisphere also controls the dominant right hand. Corresponding nerve fibers run from left to right in the lower part of the brain. In left-handed people, the right hemisphere is in control of the dominant hand. Question: What causes brain asymmetry to develop different in left-handed people?”
TUBB4B regulates proteins that assemble into filaments called microtubules, which provide the internal structure of the cell. The identification of a rare mutation in this gene, which is more common in left-handed people, suggests that microtubules are involved in shaping the brain’s normal asymmetry, said Franks.
The two cerebral hemispheres begin to develop differently in the human embryo, but the mechanism remains unclear.
“Rare genetic variants in a small number of people can identify a gene that is open to the developmental mechanism of brain asymmetry in everyone. TUBB4B is a good example of this,” he said.
The findings are based on genetic data from more than 350,000 middle-aged adults in the UK in the UK Biobank database. About 11pc are left-handed.
For most people, determining which hand is dominant can be random.
“We think that left-handedness is caused by random changes during the development of the embryonic brain without specific genetic or environmental influences. For example, random changes in the concentration of certain molecules during the key stages of brain formation,” said Francks.
Over the centuries, many cultures have distinguished themselves by being left-handed and forcing lefties to be right-handed. In English, the word “bener” means “true” or “true”. The word “sin” comes from the Latin word “to the left”. And “left hand praise” means mocking as praise.
The prevalence of left-handedness varies around the world, being lower in Africa, Asia and the Middle East than in Europe and North America.
“This represents the left hand in some cultures – allowing left-handed children to pass with the right hand even in Europe and North America,” he said.
The new findings may have implications for the field of psychiatry. Although most left-handed people do not have this condition, people with schizophrenia are more likely to be left-handed or ambidextrous, and people with autism are almost three times more likely.
“Some genes that are used in brain development early in life may be involved in brain asymmetry and mental traits. Our study found evidence for this and looked at genetic variants that are more common in the population,” he said.
