Wikipedia: RNA world hypothesis/Talk

: The RNA world hypothesis, if true, has important implications for the very definition of life. We may be too ready to define life in terms of DNA and proteins. After all, in today's world, DNA and proteins seem to be the dominant macromolecules in the living cell, with RNA serving, for the most part, as a mere messenger between them. But the RNA world hypothesis places RNA at center-stage when life originated, and therefore requires that we define life primarily in terms of RNA, and only secondarily in terms of DNA and proteins. If the RNA world hypothesis is true, life can be defined as the set of strategies that RNA polynucleotides have used and continue to use to perpetuate themselves.

Whether RNA was the first form of "life" or not is nice scientifically-falsifiable theory. But all these philosophical interpretations can't be automatically attached to the theory. Let's not forget that whenever group of organisms are totally dependent on each other in reproduction, and RNA, DNA and proteins crearly are, there is no conflict of interest between them and interpretation from POV of any of them is not any less good than interpretation from POV of others. So it doesn't need to have such philosophical implications. --Taw

How long would an RNA molecule have to live in order to reproduce itself? Granted there are two answers (one for today's fragile RNA and one for the RNA-world-type RNA); just curious whether anyone's thought about how tough RNA would have to be in order to be evolutionarily successful. --RjLesch

I recall reading somewhere about a theory that the first life used PNA instead of RNA or DNA; that's "peptide nucleic acid", IIRC. The nucleotide bases were mounted on a backbone that was joined together with peptide (protein) bonds instead of sugar phosphates, which was much more stable than either DNA or RNA in open solution. Anyone know what I'm talking about, or am I remembering phantoms? -BD

Some things a lay person asks upon reading this: who has worked on, supported, first described the hypothesis, and when did they do so?