One person’s spam is the treasure of another.
The international team of scientists found that the human genome “spam” DNA lines, which were previously written off as a non -beneficial function, are actually quite important.
The work published as a to study In the magazine Scientific progressThe focus is on the transferable elements, the DNA sequence class, which can “jump” through the biological copy and paste mechanism, to different parts of the genome. These “jumping genes” occupy almost 50 percent of human DNA; In other organisms, the proportion is even greater.
What found by investigators from Japan, China, Canada and the United States is that a certain family of these TEs, called Mer11, can have a profound effect on gene expression and act as “genetic switches” – actually without changing the main DNA.
“Our genome has been followed a long time ago, but many parts of it remain unknown,” Fumitaka Inoue, a co -author of a study, said a. a statement about work.
Mer11 sequences are called long terminal repeat (LTR) retrotransposons. It is believed that this came from endogenous retrovirus (ERV), which infected the Simian’s ancestor tens of millions of years ago, capturing cell DNA, which invaded copies of his genetic makeup, which never disappeared but remained inert. Researchers, at least eight percent of the human genome comes from these retroviruses.
That, besides, all the other TE, rising our genome, creates a lot It is a shame that human scientists can sift. The authors say that current methods of classification and annotation are inaccurate, so DNA sequences are unobtrusive as a genetic spam. This encouraged them to try their own classification system.
“Proper classification and annotation of LTR copies is very important in understanding their development, cooperation and potential impact on the host,” the authors wrote in the study.
Researchers’ statement states that the investigator’s system has classified MER11 sequences according to their evolutionary relationship and how well they were preserved in prime genomes. They then divided Mer11 into four separate subjects Mer11_G1 per G4, based on their age.
This allowed the team to compare the Mer11 subspecies with the so -called Epigenetic signs: chemicals that can affect the way important proteins work, works, And it affects gene activity. Most importantly, the epigenetic signs are not required to physically replace the cell DNA to modify the cell’s behavior, such as silence the gene that should be expressed. By accurately linking the MER11 sub -markers, there is the main step to reveal the extent of their expression of genes.
Since it was like a springboard, the team tried about 7,000 Mer11 sequences from people and primates, measured how much everyone affected gene activity, and found that the youngest in Mer11 Post G4 had a strong ability to influence gene expression – further.
“Young Mer11_G4 connects to a separate set of transcription factors, stating that this group has acquired different regulatory functions by changing the sequence and contributes to the specification,” said the author of the main author Xun Chen from the Chinese Academy of Sciences.
The effect is fascinating. Although these DNA strands may have begun as “spam”, they gradually encouraged their way to play the role in gene regulation today, showing a huge part of the unknown history of evolution that only scratches the surface.
“It is believed that the transposed elements play an important role in the evolution of the genome, and their significance is expected to become clearer as research continues to improve,” Inoue said.
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