The Origin of Viruses

You don't need them to remind you that, despite their little, viruses may have a massive impact on the planet. Viruses are technically not "living" because they cannot reproduce, instead multiplying within the cells of host creatures ranging from enormous mammals to single-cell bacteria. This frequently has a negative impact on the hosts and can even kill them, therefore it is no wonder that scientists have studied viruses extensively in order to learn as much as possible about them. This raises an important question: where did viruses originate? Their genesis is extremely difficult to research because they left no physical fossil record, so they don't even know where to position them on the evolutionary history. The "virus-first hypothesis," as it is known, places them at the very beginning, before the formation of cellular life.

The regressive hypothesis proposes that viruses evolved as single-cell organisms began to create mutualistic interactions. The relationship became parasitic over time as the smaller of the two creatures gradually became dependent on the larger and lost the ability to produce proteins, but retained the ability to replicate and evolved into a virus.

The progressive or escape theory proposes that viruses arose from fragmented pieces of genetic material that managed to escape their originating species and attach themselves to others. These are the three most common hypothesis on the origin of viruses, but they are far from the only ones, and none of them has received sufficient support to be called definitive. Unless a huge breakthrough occurs, it is very probable that this will remain a mystery for the foreseeable future.