United States: According to the latest study, out of the total human DNA, 8 percent are made by viruses, which have not existed for millions of years.
These sequences, known as human endogenous retroviruses (or Hervs) characterized to be hundreds of thousands to millions of years old; some even predate the emergence of Homo sapiens, sciencealert.com reported.
More about the news
Some of the new research identified that certain archaic viral DNA elements of the site have a role in psychiatric disorders, including schizophrenia, bipolar disorder, and major depressive disorder.
These resemble endogenous infections with ancient retroviruses, and Hervs stands for Human endogenous retroviruses. Retroviruses are viruses that enter the cell and insert a copy of their genetic material inside the DNA of the cells in which they enter.
It is likely that retroviruses contaminated us more than once at sometime in our evolutionary development. It is likely that these viral infections also occurred in germ cells that gave rise to offspring; in this case, the genetic material from the retroviruses became integrated into the organisms’ lineage and remained there permanently, sciencealert.com reported.
About Hervs discovery
At first, researchers believed that Hervs were remnants of “junk DNA,” which are essentially useless debris embedded in our DNA.
However, with revelation of the first few years of understanding the human deoxyribonucleic acid, it has been discovered that such non-coding DNA does contain more functions than was initially assumed.
The first scientist discovered that Hervs might have the capability to control the expression of other human genes. An another term used in the genetic description refers to the process of yielding RNA molecules for a given DNA segment as ‘expression’ of the phrase.
They can then act as a kind of bridge to the synthesis of certain proteins or another part of the genome.
More about the functioning of Hervs
Early investigation revealed that Hervs control the activity of another gene that plays critical aspects in living organisms. An example is a Herv that controls the expression of a gene that encodes an enzyme with a role in modifying circuitry connections between neurons in brain.
Hervs have been also detected to synthesize RNAs and sometimes even proteins in blood and brain tissues. Focusing on these molecules, it may be possible to point out their versatility since such signaling molecules can move between different cellular compartments to perform various tasks.
Hervs’s role in psychiatric disorders
Given the enormous number of Hervs and their possible multiple functions, the researchers decided to verify the hypothesis that variability in the level of Herv expression is directly linked to genetic predisposition to certain forms of psychiatric disorders.
To further investigate the relationship between Herv and neuropathology. This made it possible for us to establish various regions of the DNA that defined Herv expression in the brains.
This information was compared with data obtained from large genetic studies by drawing an analogy of variation between tens of thousands of individuals with mental health disorders and those without them.
These studies pointed out the fact that there are these genetic signatures that are now linked to several psychiatric disorders.
In this regard, the researchers ascertained that Hervs plays a significant role in the pathology of major psychiatric disorders as the level of four Hervs was associated with the genetic predisposition to the illness.
Out of these Hervs, the use of two was linked with schizophrenia; one Herv was connected to both schizophrenia and bipolar disorder, and lastly, depression was connected to one Herv.
Therefore, as per the researchers, by linking various Herv expressions in the brain with psychiatric disorders, it is recognized that importance lies in understanding these mysterious sequences in the human genome, which have been ignored for years.