JAKARTA - Red hair is often the subject of ridicule and is often labeled as having a hard temper. However, The Guardian, quoted on Sunday, April 19, reported that the latest genetic study found that the red hair gene in Europe was actually actively selected by nature for more than the last 10,000 years.
This finding is not just about hair color. From the analysis of DNA of nearly 16,000 ancient human remains and more than 6,000 modern people, researchers see that human evolution has not stopped. Natural selection is still at work, even allegedly speeding up after humans switched from hunting and gathering to farming.
Researchers found 479 genetic variants that seem to be favored by natural selection. Among them are genes related to red hair, light skin, susceptibility to celiac disease, as well as variants associated with reduced risk of diabetes, baldness, and rheumatoid arthritis.
For red hair and fair skin, the explanation is considered reasonable. Previous research has shown that these two traits help the body produce vitamin D more efficiently, especially in sun-poor regions. In the northern region, this advantage can affect the chances of survival.
As The Guardian wrote, the study also shows that in evolution, what is now considered bad is not necessarily harmful. Mutations known as major risk factors for celiac disease, for example, have become more common since about 4,000 years ago. Likewise, the immune gene TYK2 that increases the risk of tuberculosis. Its frequency had risen for thousands of years before finally falling again.
This means that genes that now seem to be harmful could have actually helped humans survive. Evolution does not always select for traits that seem healthiest or most ideal by the standards of modern humans. In certain situations, genes that are now considered problematic could have helped humans fight pathogens or survive in harsh environments.
Researchers also found negative selection on combinations of genes that promote high body fat percentages. They attributed this to the "hematozoic gene" hypothesis. When food is scarce, the ability to store fat is an advantage. But after agriculture made food supplies more stable, that trait could turn into a burden.
"With this new technique and the sheer amount of ancient genomic data available, we can now see how selection shapes biology directly," said Dr. Ali Akbari of Harvard University, lead author of the study.
This finding is important because it challenges the long-held assumption that human evolution slowed down after the emergence of farming societies. In fact, changes in the way of life seem to have contributed to biological changes in the human body.
Even so, the results of this research published in the journal Nature have limits that need to be noted. This study focuses on Western Eurasia, according to the origin of the DNA samples analyzed. That is, the findings are not automatically valid for all populations in the world.
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