Humans are Eight percent Virus : Viral Genes in Human DNA

Yes, you heard it right. Human DNA has traces of genetic material of some ancient Viruses. They are part of human genome and it become evident on completion of Human Genome Project. It is really hard to find those genes in human genome as it is like finding a needle in haystack. Previously it was thought they these genes in human body are idle and don't function, but later researchers found that they are there for a purpose and may be helping us to increase our immunity.

How did Virus Genes enter the human genes permanently ?

When a virus infects the human body, it transfers its genetic material into the infected cells and alters the DNA of that cell. But it can't be permanent part of human genome. Researchers believe that millions of years ago some retrovirus infected ancestors of humans and entered sperm cells. When those infected sperm cells were used in fertilization during normal reproductive process, they created an infected offspring which has got those viral genes. In the beginning it must have been like some inborn disease, but as generations progressed genetic mutations occur and those genes were altered and shutdown by our immune system. As the time progressed those viral genes spread in whole humanity.

Are those ancient viral genes helping us today ?

Some of these viral genes sits near those human genes which are responsible for immunity. Some more research made scientists believe that those viral genes are improving our immunity and help us fight against infections in a better way. Those genes might be a reason behind survival of human race for so long. Those genes must have helped in evolution of humans.

Some researchers believe that we have got hundreds of genes from bacteria, archaea, fungi, other microorganisms and plants we we have evolved from those forms of life. We are not something directly created. We have evolved from a number of other forms of life and thus contain genetic material from a number of those old species.

Unknown facts about Viral Genes in Human DNA

• We have got around 100,000 pieces of DNA that come from retroviruses. It means our 5 to 8% DNA is made up of virus genes.
• Syncytin is a protein which is essential in building placenta in mammals. A viral gene is responsible for creation of this protein. If this gene would not have been there then mammal evolution might have taken some other turn and humans might not have been formed.
• Hemo is a protein made by a fetus and the placenta. This protein is produced from viral DNA that entered our ancestors’ genomes 100 million years ago. Its usage is still unknown.
• Viral Genes in Human Genome are the primary reason that we can fight most of the viral infections on our own.
• Some researchers believe that development of fetus is impossible without viral genes in our body. Some viral proteins are made around fetus for unknown reasons which might be holding some unknown key to fetal development.  

Some researchers feel that viral genes are part of human genome and it will take time to find which one are good and which one are bad. But like everything else it has got two sides of the coin. Some genes might be increasing our immunity but some might be making us prone to killer diseases like cancer.