8% of human DNA is synthetic. Genetic sequences from ancient viruses. These sequences, known as human endogenous retroviruses (or Herves), are hundreds of thousands to millions of years old – some even. Before it happens A smart man.
Ours Recent research Some ancient viral DNA sequences in the human genome play a role in susceptibility to mental illnesses such as schizophrenia, bipolar disorder and major depression.
Hervis represents the remnants of these infections with ancient retroviruses. Retroviruses are viruses that insert copies of their genetic material into the DNA of the cells they infect.
Retroviruses may have infected us. In many cases In our evolutionary age. When these infections occurred in the sperm or egg cells, when they gave birth to children, the genetic material of these retroviruses was present. It is passed on to the next generationBeing a permanent part of our race.
At first, scientists thought of Herveys as “junk DNA”—parts of our genome with no known function. But as our understanding of the human genome has advanced, it has become clear that this so-called junk DNA is responsible for more functions than originally hypothesized.
First, researchers discovered that Herpes can control the expression of other human genes. A genetic trait is said to be “expressed” if the DNA segment is used to make RNA (ribonucleic acid) molecules.
These RNA molecules can act as intermediates. Production of certain proteinsor help to control of other parts of the genome.
Preliminary research has suggested that Hervis regulates the expression of neighboring genes with important biological functions. One example of this is Herv, which regulates gene expression involved. Fixing relationships between brain cells.
Herves are known to produce RNA and even proteins. in the blood And Brain samples. These molecules have the potential to exert a wide range of functions as they can travel through cellular compartments to perform various functions.
Scientists have found evidence that some human genes are derived from Herveys. This suggests that there have been instances during evolution where Herves have been co-opted for specific biological functions.
For example, the human genes syncytin 1 and 2 from Herpes play an important role in Plant growth.
Herveys in mental disorders
Given the abundance of Hervis in the genome and their many potential functions, we want to better understand whether genetic susceptibility to certain mental disorders is associated with variations in Herv expression.
In our studyWe characterized Herv expression in nearly 800 cadaveric brain samples. This helped us identify the DNA variants that affected Herv expression in the brain.
Then we checked this information with findings Large genetic studies It compared genetic differences between tens of thousands of people – with and without mental health conditions. These studies have identified DNA variants associated with various psychiatric conditions.
We found that the expression of four HEVs is associated with genetic susceptibility to major psychiatric disorders. Expression of two of these HerVs was associated with schizophrenia, one HerV with both schizophrenia and bipolar disorder, and one with depression.
These results suggest that Hervis may be playing a more important role in the brain than originally thought.
There are many genes involved in mental disorders – and Hervey’s is only one piece of the puzzle. Although the exact impact of these viruses on brain cells and a person’s susceptibility to certain psychiatric disorders requires further study, our study is the first to show that genetic susceptibility to psychiatric disorders also operates through these ancient viral DNA sequences.
It is still too early to determine the practical application of our findings – and whether they can be used to develop new treatments. But we are optimistic about this line of research.
By linking Herv expression in the brain to psychiatric disorders, our research sheds light on the importance of these secretory sequences in the human genome that have been overlooked for years.
Rodrigo Duarteresearchers, King’s College London; Douglas NixonProfessor of Immunology in Medicine, Cornell UniversityAnd Timothy Powellsenior teacher, King’s College London
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