How did the earlier form of cellular life that existed 3 billion years ago disappear? Have they been plagued by viruses? Viruses! Did virus exist during that period? A newly discovered virus, including the existing ones seems to share a common design principle. It can be deduced from this, that these modern viruses also share a common ancestor that appeared before different viruses evolved to infect the three main domains of life: bacteria, archaea and eukaryotes. According to a virologist, viruses are as old as life itself, if not older! By studying a virus newly isolated from Sulfolobus solfataricus, an archaean found in acidic hot springs in Yellowstone National Park, Mark Young and his colleagues reached this conclusion. The unique shape and DNA sequence of the virus forced the virologists to be confident with their deductions.
Via: New Scientist