Patrick Forterre of the University of Paris-Sud has also analyzed enzymes liable for DNA replication and has concluded that the genes for such enzymes in eukaryotes probably have a viral origin. Further analysis by Stanley and others established that a virus consists of nucleic acids (DNA or RNA) enclosed in a protein coat which will additionally shelter viral proteins concerned in an infection. By that description, a virus seems extra like a chemistry set than an organism. But when a virus enters a cell (referred to as a number after infection), it is far from inactive.

Examples of vertical transmission …