Over years and years of evolution, retroviruses have ingrained themselves in our genomes and currently contribute to 10% of it. Now research has shown how these viruses have a great deal of impact on the gene expression as well as the human brain development.
Retroviruses are a group of viruses that include dangerous (e.g. HIV) as well as harmless ones. In the Lund University, research is being carried out on endogenous retroviruses (ERV) that make up part of what is titled as "junk DNA". Now scientists are reconsidering the notion of useless DNA.
Genes that control the production of protein make up only 2% of the genome in comparison to the retroviruses' 10 percent. Researchers have discovered that what the discarded as part of the useless DNA indeed acted as a "docking platform" helping in the production of a specific protein "TRIM28".
This protein acts as an off switch for viruses as well as other genes adjacently aligned in the DNA helix. This ultimately helps the presence of ERV to influence gene expression. As this switching mechanism operates differently from person to person, it makes it susceptible to being a probable tool in evolution as well as a cause, however small, in neurological disease.
Some studies confirm that the "deviating regulation of ERV" was spotted in multiple cases of schizophrenia, ALS and bipolar disorder cites Science Daily. A study made by the team nearly two years ago showed the role played by ERV in neurons. But, as it was conducted on mice, the team decided to redo the experiment only this time using human cells.
It was important to redo the experiment because the specific retroviruses contained in the human genome are not found in species other than humans, chimpanzees and gorillas. The incorporation of these retroviruses seems to have begun almost 35 million years ago when primates' evolutionary lineage was split into the New and Old World.
Scientist Johan Jakobsson says that the development of the human brain may have been contributed to by the mechanisms affected by ERV. This information was collected directly from materials supplied by Lund University.
It looks like there is much more that is yet to be discovered about genetics' role in brain development.
