Did viruses exist before bacteria ever existed on Earth?
No, viruses (virii?) need bacteria to live.
They probably evolved from parasite bacteria or even from bits of raw nucleic acid that got out of bacteria cells.
That's a new one on me. They simply need some other living organisms to proliferate, don't they?
Your point seems reasonable though. I've taken it as nearly axiomatic.
They need cells and the only cells around at the time were bacteria. Virus now infect just about everything.
OK. Got it.
Consider some RNA split-off from a parent bacteria--our progenator viral cell. The mechanisms by which it proliferates is contained in the species of organism from which it split. It becomes a predator, or parasite upon the relatives from which it sprang.
They do have some good points, they swapped a lot of genes with early cells and may even have contributed to inventing sexual reproduction.
Now that's interesting. It seems you're ahead of me.
I was considering what the equivalent protogenic software would be like on a computer. Most likely it would be a corruption (mutation) of some elements of the supervisory program. The difference, as it stands today, is that most supervisory corruptions don't have the opportunity to proliferate to supervisories elsewhere.
Viruses. There is no plural for the Latin virus[/url]. Since it is now an English word with a different meaning and usage, the English rules for pluralization apply.
the rna world hypothesis suggests that rna molecules were able to survive and reproduce before bacteria existed.
Do I have this right? Do all viruses require the DNA or RNA of another organism to synthesize molecular elements to construct their own structure?
Viruses require the molecular machinery and building blocks of another organism to replicate (i.e. enzymes, nucleotides, amino acids). They provide their own DNA or RNA. To address the original question, almost by definition "bacteria" would have to have existed before any phage (a bacterial virus) because of a phage's inability to independently self-replicate. However, it seems logical to me that the earliest true viruses probably showed up very early on, taking the form of self-replicating genes that could insert themselves into the nucleic acid polymers of early protocells. Today, these self-replicating genes are known as transposons and are found in all forms of life. In my opinion, bacteriophages, viruses, and plasmids probably evolved from these early "genetic parasites".
Thanks james. That's what I'd gathered, but wasn't sure. This close association would almost demand that viruses were the 'unexpected' prodigy of what would become their first hosts, wouldn't it?
Obviously, abiogenesis is still unclear.
Here's an interesting article by Zimmer from Science a few years back about how viruses may have helped shape life: http://www.sciencemag.org/cgi/content/summary/sci;312/5775/870
Separate names with a comma.