Viruses are being redefined as more than just pathogens. They are also critical symbiotic partners in the health of their hosts. In some cases, viruses have fused with their hosts in symbiogenetic relationships. Mutualistic interactions are found in plant, insect, and mammalian viruses, as well as with eukaryotic and prokaryotic microbes, and some interactions involve multiple players of the holobiont. With increased virus discovery, more mutualistic interactions are being described and more will undoubtedly be discovered.
Sourced through Scoop.it from: jvi.asm.org
Some day we may realise that this is the norm for viruses – and that what we thought we knew about viruses is simply the behaviour of a simplistic and destructive subset of them that we labelled "pathogens".
It is beyond question that all organisms on this planet have evolved in the midst of a cloud of viruses: they have certainly shaped the evolution of immune systems and responses, let alone having directly influenced our evolution in ways like conferring cell fusion ability on cells that become the placenta in mammals.
It should therefore come as no surprise that viruses are very often commensals and even symbiotes. While we generally don’t understand just how we and our other cellular brethren might benefit from intimate association with viruses, I am sure that every new virome will shed light on this – as well as unearthing more and more of the biological dark matter that is viruses.
Nice one, Marilyn!