Ancient viruses played a role in the advanced development of our brains. A retrovirus invaded the DNA of several species hundreds of millions of years ago.
It proved crucial in spreading the impuls of myelin, an insulating fatty membrane that forms around nerves and allows electrical impulses to be distributed more quickly. Researchers searched genome databases to try to uncover genetic factors associated with myelin production, which is found in modern mammals, amphibians and fish. The study was called a "fascinating insight" into the history of our jawed ancestors by Brad Zuchero.