A new study has provided important information for scientists who are puzzled by the secret to some people using the right or left hand, and while it appears that many environmental factors interfere greatly with this issue, many scientists have long adopted the theory that it is possible that there is one dominant gene that is the underlying cause. The right hand is popular with many people all over the world.
The writer Robert Lee Hotz said that in his article published in the American Wall Street Journal (wsj), scientists have discovered through new studies that included millions of people that the secret lies in dozens of genetic differences that constitute our preference for the use of the right or left hand.
Brain imaging studies
Hotz pointed out that the issue goes beyond the hand we prefer when throwing the ball or holding the pen, and it relates to the difference in language, facial recognition and some other sensory perceptions in terms of location and intensity across the cerebral hemispheres.
Brain imaging studies indicate that these nerve signals are processed by one side of the brain, and this explains the preference for using one hand over the other.
The preference for one hand shapes our behavior, from the way we hug people to kick our football to the side we like when we take selfies.
The ideas about right and left are so ingrained that they shape the way we talk about ethics, creativity and politics.
“This is the essence of our brain system and our nervous systems that influence our behavior,” says psychologist Sebastian Ockelenburg of the Ruhr University in Bochum, Germany – who studies the hand preference between humans and animals.
“Although many people think they choose to do a lot of things of their own free will, it is the ancient cerebral principle that shapes all kinds of our simple daily practices,” he adds.
Animals also prefer one cache over another
Several studies have shown that many types of dogs, cats, and even Japanese spider crabs prefer to use one of the claws in roughly equal numbers.
In contrast, about 90% of people use the right hand, but no one knows the exact reason behind this, nor why a large minority continued to use the left hand from tens of thousands of years even before prehistoric times.
Even if the genetic aspects of left-handed people become clear to scientists, science might conclude that genetic factors play a small role in this preference.
Geneticist David Evans of the University of Queensland in Australia – who was also a lead author in the new study on multiple genetic factors – shows that “environmental factors play a role in favoring the use of one hand.”
The year in which a person is born, his birth weight and whether he belongs to a twin group are all factors influencing this issue, according to the data collected by the British Biobank.
North and South of the ball
Other researchers found that the percentage of left-handed births is higher in the spring and early summer months in the Northern Hemisphere, while the percentage of left-handed births appears to be higher between September and January than the Earth in the Southern Hemisphere. Earth.
Gender differences play an important role, as studies show that slightly more men use the left hand than women, and geographical and cultural factors are responsible for the preference for using one hand.
According to research published last year, the rate of people born in the United Kingdom who use the left hand was 10.1%, while the percentage of residents and those born elsewhere decreased to 6.8%.
Racial differences are likely to affect the use of one hand, as a study showed that 3.5% of schoolchildren in China and only 0.7% in Taiwan were difficult, and left hand use is less in Asia than in North America or Europe.
Greek scientist Marietta Papadato Basto of the National Ecapodistrian University in Athens and her colleagues collected data from nearly 2.3 million people worldwide, in 200 published studies.
According to results published in April in the journal Psychologyul Beltan, Dr. Papadato Pasto and her team estimate that 10.6% of people around the world use the left hand, or about 827 million people.
According to a new study on multiple genetic differences, published in the journal Nature Human Behavior and included 1.7 million people, an international group of 118 scientists discovered only 41 active genetic differences between left-handed people, and 7 other genetic changes associated only with able-bodied people. To use both hands equally.
The scientists’ conclusions were based on anonymous genetic data collected by the British Biobank, 23 & Me biotechnology company (23andMe) and 32 research groups.
Although researchers are not sure of the effect of the genetic differences, they suspect that hundreds if not thousands of these differences may be related to hand preferences, many of which appear to be related to brain development.
The writer quoted what was said by the scientists who explained that the previous studies were simply narrow in scope and did not discover the genetic effects, explaining that many studies ignored the hardship.
Until recently, neuroscientists have routinely excluded left-handed people from brain imaging studies designed to explore brain function.
According to several neuroscientists and psychologists, most studies have focused on right-handed men in order to simplify the results.
The writer concluded by saying that neuropsychologist Susan Bockheimer of the University of California said, “It has been appropriate to exclude people with disabilities in brain imaging studies conducted in light of a small number of research.”
According to Dr. Papadato Pasto, hundreds of studies have tried to solve this puzzle of using one hand over the other, but their efforts have failed, as even for indigenous peoples 10% of them were difficult for an unknown reason.