IPB University Geneticist: Don’t Be Bullied, Kidal Children are Not a Disgrace
IPB University Geneticist: Don’t Be Bullied, Kidal Children are Not a Disgrace
In certain circles of society, the use of the left hand is considered taboo, impolite and inappropriate. Left-handed children are considered a disorder, even families are often blamed for being unable to educate their children to use the right hand.
It is unusual for left-handed children to be considered a disorder and a disgrace that leads to ridicule and bullying, not only from their peers but also from family members.
Victims of Incomprehension
According to Prof Ronny Rachman Noor, an Ecological Geneticist at IPB University, until now the cause of left-handedness is still not widely understood by the public. This ignorance often has a negative impact on left-handed children and left-handed adults.
“Various studies show that left-handed children often face challenges and difficulties in their learning and daily activities. Because of this condition, they are more prone to emotional instability and have the potential to cause frustration and anxiety. Moreover, almost all existing facilities and equipment are designed for children who are not left-handed,” said Prof Ronny.
Empirical data shows that most people in the world (90 percent) use their right hand more in their activities. The percentage of left-handed people only reaches 10 percent.
Between these two groups, there are about 1 percent of people who can use both hands equally well and effectively. This last group is known as “ambidextrous”.
The percentage of left-handers in Western countries reaches 10,6 percent, much higher than that in Asian countries. For example, the percentage of left-handers in China is only 2,64 percent, while the percentage of left-handers in Indonesia is 3,39 percent. In three other countries such as Vietnam, Hong Kong, and Taiwan, the percentage of left-handers ranges from 4,26-5,16 percent.
“There are also studies that show that left-handed children are more prone to suffering from ADHD (Attention-Deficit/
Other research shows that left-handed children have different brain activity patterns compared to right-handed individuals. This can lead to differences in learning and cognitive abilities.
Left-handed Children: A Product of Family Miseducation?
According to Prof Ronny, in the midst of various challenges and difficulties that must be faced, left-handed children often develop into children who are more creative, have better resilience and better adaptability to the surrounding environment.
“Left-handedness is not a disgrace but a trait whose emergence is influenced by genetic and environmental factors. By understanding the process of the emergence of this left-handed nature, we will be able to make left-handed children as superior human resources,” he said.
The Professor of the Faculty of Animal Science, IPB University, said that left-handedness can be physically detected when the fetus is 9-10 weeks old by observing the movement of its hands. This left-handedness becomes clearer when the child is 2-3 years old.
“The results show that left-handedness is influenced by several genes (polygenes) not a single major gene. In quantitative genetics, the parameter used to determine the percentage of variation in genetic influence is the heritability value,” explained Prof Ronny.
He further explained that the genes that contribute to the emergence of left-handedness are estimated to number up to 40 genes that jointly work and interact with the environment to give rise to left-handedness.
“The results of the latest research explained that one of the genes that plays a more prominent role in causing the emergence of left-handedness is the TUBB4B gene. This gene functions to encode proteins involved in cell structure and rare coding variants in this gene are more common in left-handed people,” he explained.
However, he continued, the presence of certain allelic variations of this gene does not necessarily lead to left-handedness.
Prof Ronny explained that the emergence of left-handedness is a combination of genetic and environmental factors. Various studies have revealed that the heritability value of left-handedness is 0,25. This means that variations in left-handedness are influenced by genetic factors as much as 25 percent. This means that the variation of left-handedness is more (75 percent) influenced by the environment.
“The results also show that some environmental factors that are thought to trigger the emergence of left-handedness include uterine conditions such as hormone exposure and fetal position during pregnancy. Hormonal fluctuations during pregnancy, especially testosterone, are thought to affect fetal development and hand orientation,” explained Prof Ronny.
After birth, environmental factors that are thought to affect hand orientation are culture, birth weight and type of birth. Babies born in a cultural environment where left-handedness is taboo will reduce the number of left-handed children.
Studies have also shown that low birth weight and multiple births can lead to left-handedness. In some cases, not breastfeeding a baby can trigger left-handedness.
“As an illustration, from a genetic point of view, if both parents are left-handed, the chance of the child being left-handed only reaches 25 percent. So, by chance it can be said that the chances of a left-handed child from parents who are both left-handed are greater than if the parents are not left-handed,” said Prof Ronny.
The question that often arises is “Can a right-handed parent have a left-handed child?” Even if both parents are right-handed, there is still an 11 percent chance of them having a left-handed child.
The Percentage of Left-Handed People is Declining
In terms of evolution, Prof Ronny explained that empirical data shows that over time there is a decrease in the percentage of left-handed people. This decline will lead to a balance point between the need to live in groups, work together, and human evolution.
“As we know, along with the evolutionary process, humans live in groups, and work together and develop various equipment for their daily needs. Therefore, the process of evolution and adaptation is more towards people who are right-handed,” he explained.
The selection that has an impact on reducing the percentage of left-handed people is known as directional selection, which leads to an increase in the number of non-handed people. (IAAS/NVA)
