Secret genetic code discovered in human DNA

An international team of scientists has discovered that DNA sequences, once thought useless, actually control the activity of genes. The discovery reveals a forgotten part of the human genome's evolutionary history.

Evolution in the human genome still has many secrets and needs more in-depth research in the future - Photo: AI

For decades, scientists have believed that nearly half of the human genome is “genetic junk,” DNA fragments that do not code for proteins, have no known function, and are essentially useless genetic remnants. But a new study published in Science Daily is changing that view completely.

The research team, which included scientists from Japan, China, Canada, and the United States, focused on a special group of genetic elements that can “jump” in the genome, called transposable elements (TEs). These pieces of DNA can move from one location to another in the genome in a biological copying mechanism, much like cutting and pasting.

In humans, these elements make up nearly 50% of the genome, and are even more common in many other organisms.

The highlight of the study is the MER11 group, a special TE family belonging to the LTR retrotransposon (DNA segments with repeated sequences at both ends). According to scientists, MER11 originated from an endogenous retrovirus (ERV), an ancient virus that invaded the cells of primate ancestors tens of millions of years ago. This virus left a genetic mark in the DNA and passed down through generations to this day.

Although most of these ERVs are no longer active, research suggests that at least 8% of the human genome originated from ancient viruses, and some of them are still silently influencing current gene activity.

The team found that MER11 is not just a genetic relic, but acts as a switch that controls gene activity without changing the original DNA sequence. They found that MER11 has the ability to strongly influence gene expression, that is, how much and when a gene is turned on or off.

To dig deeper, scientists classified MER11 into four subgroups according to evolutionary age, from G1 - G4. Of which, the youngest group, G4, showed the strongest influence on gene expression.

The secret is that the MER11_G4 fragments contain special DNA sequences that can “attract” transcription factors, proteins that activate or repress genes. This allows MER11_G4 to intervene in which genes are turned on or off, contributing to the differentiation of primates, including humans.

This discovery not only sheds light on the potential role of previously “useless” DNA segments, but also opens up a new direction in the study of human genome evolution. Transposable elements (TEs), especially MER11, are thought to play an important role in shaping and regulating the genome over evolutionary time.

"The human genome sequence has been decoded for a long time, but the functions of many parts of it remain a mystery," said study co-author Dr Fumitaka Inoue from Kyoto University.

Research results show that, instead of being "genetic junk", jumping elements like MER11 are actually a secret genetic code system, working silently to coordinate the survival of cells, while preserving traces from ancient times in evolutionary history.

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MINH HAI

Source: https://tuoitre.vn/phat-hien-ma-di-truyen-bi-mat-trong-adn-nguoi-202507271515518.htm