| Every time evidence leans the author towards "viruses might come from space", I find myself leaning the other way. My general view is that cellular life and viruses mutualistically co-evolved from life-like junk at the very beginning. Cells provide the metabolisms necessary to fight entropy. Viruses promote genetic diversity while acting as a stress-test to ensure cells can survive their environments. This seems separate from the trichotomy offered:
- Virus first
- Reductive virus
- Escaped genes "If viruses originate from the cells that they interact with, one would expect there to be significant genetic overlap between the host and the parasite" The generally small amount of genetic material in a virus is being used for viral reproduction. I assume most functions encoded in the genomes of cells are useless and expensive for a virus to replicate. Hence, they'll drop out; we'll be left with oddball viral genes for viruses to do virus things. [clipped list of reasons]
"All of these facts together suggest that viruses are the raw material from which living creatures build their genetic material. They’re like bricks in a building, ..."
I think of viruses more as clipboards (like copy-paste in your OS). Great for moving info around, but wholly dependent on a cell metabolizing somewhere. Hardly building blocks. "If that’s the case, it’s possible that the absolute simplest viruses, ones who consist of genetic information encased in a capsid made from a single repeating subunit, could be abiotic products of the cosmos. If that’s the case, we would expect to still find viruses as you got further and further away from the surface of the Earth." Considering the density of viruses in the ocean (mentioned by the author), it seems a simple gust of wind would be enough to cover the earth in viruses. I believe extraterrestrial life is nearly certain and that viruses can survive in space. I also think viruses depend on host cells to reproduce. A virus would have to land in the primordial soup to be of any life-generating use. By that point there would be enough lifelike junk for the virus to be an unnecessary step in the recipe. |