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Comment by johnnujler | Hacker News Reader

Every thing about life is so fascinating. I have always wondered how viruses have persisted for so long if they need a host to survive and it took us millions of years to go from single celled to multicellular. I wish there was a way to know everything and become good at everything. :/

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I think the plain answer is that if they didn't, you wouldn't know about them. Just like all other parasites. In some sense, we're all parasites on plants, that in turn feed on the energy delivered by the giant fusion reactor in the middle of our solar system.

In the case of viruses, remember that there are viruses for much simpler organisms, like bacteria. And yes, you can use those to treat bacterial infections.

> In the case of viruses, remember that there are viruses for much simpler organisms, like bacteria. And yes, you can use those to treat bacterial infections.

Those are called bacteriophages (a misnomer, since they don't actually eat bacteria).

I have a theory that bacteriophages originated as a biochemical weapon for inter-bacterial competition.

If you think about it, the ability to produce packets that target and penetrate a competitor's cellular wall and inject a payload is pretty useful. Payloads could be as simple as a toxin to start.

From that point, you could have stepwise improvements for deliverables that disrupt reproduction in the target (for example by cutting apart DNA strands), by inserting junk genetic material to evade self repair mechanisms, by inserting or removing specific genetic sequences to create other vulnerabilities, that insert the specific genes to make copies of the delivery system and various payloads (this is useful even if the 2nd gen copies are poor and don't include those same genes), and then finally a fully self-reproducing package that can spread exponentially.

At that point the 'weapon system' can evolve independently, and indeed co-evolve with it's target/host to (probably) jointly outcompete other species including the originating species.

Even prior to full self-reproduction, proto-viroids might act as a horizontal gene transfer mechanism that can exhibit familiar 'selfish gene' patterns and mediate various feedback loops between bacterial species. After 'escape' any species remaining with proto-viroids mechanisms would likely be parasitized and bootstrapped into actual viruses through competition and crossovers, or have those mechanisms suppressed into remnants indistinguishable from endoviruses (presuming endoviruses can even be identified in organisms as simple as bacteria).

An arms-race of proto-viroid attack vectors might also be the antecedents of and/or the driving force behind the need for various organelles that distinguish the more complex eukaryotes from bacteria.

"In some sense, we're all parasites on plants, that in turn feed on the energy delivered by the giant fusion reactor in the middle of our solar system."

I think that's wrong. By definition, a parasite interacts with a living organism. For example worms that eat the remnants of fallen leafs are not parasites, they are saprophytes. Humans as well can live consuming bits of fallen fruits that do not take part in plants' further reproduction (i.e. fruit's seeds) and would otherwise just rot (and can thus be considered dead tissue).

Fruit eating is a case of symbiosis.

> I wish there was a way to know everything and become good at everything.

There must be some way to do it, because I constantly encounter people on the Internet, that know everything, and are good at everything.

I can’t get any of them to tell me how they do it, though...

I wouldn't say everything, but I have encountered such people too. Extremely knowledgeable and always curious. It feels as if these guys somehow have more energy to expend than most of us. On the contra, I get burnt-out pretty quickly when I try to push myself beyond an arbitrary threshold which I have never been able to measure.

Viruses are ultimately bits of genetic code wrapped in a shell and injection mechanism. IANAB, so this is pure conjecture, but: it wouldn't surprise me if it turned out that viruses are a kind of degenerative state - something evolution may just spit out as it makes mistakes trying to improve on cells. If that's the case, then viruses may exist simply because they are a waste product of natural selection of more complex life.

There are some hypotheses that viruses are involved in the origin of life.

https://www.frontiersin.org/articles/10.3389/fmicb.2019.0052...

This implies that evolution has a goal and that we are that goal. This shows a fundamental misunderstanding of evolution of natural selection that is common.

Who is to say that viruses won't be the end result of life on the planet earth?

Complex life <> more evolved life. It's just differently evolved.

I know that evolution doesn't have a goal. I may have antropomorphosized it too much, but my goal was to follow a sort of temporal/casual trail that we find interesting.

The way I imagine my idea is that, if you pick a species and its interesting descendants, and order on a timeline like such:

  A --> B --> C --> D

What really happens is more like:

  [bunch of other spinoffs]
    ^
    |
  A --> B --> ...

And that some of those spinoff could be viruses. Imagine a mutation to A causes a bunch of functionality in the organism to shut down (and in subsequent generations disappear), while leaving a viable organism. For a sufficiently uncomplicated A, the result of such mutation could be a bundle of genes wrapped in a shell with an injection mechanism. That's a virus.

There are some viruses that are so large they're as complicated as actual living things.

https://en.wikipedia.org/wiki/Nucleocytoviricota

However, none of them seem to be related to anything on the official tree of life.

That would certainly be nice in some ways, but then you'd deprive yourself of the joy of learning.

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