Talk:PNA

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Just out of curiosity, i've never heard of PNAs as progenitor molecules... any good papers on the subject? Graft

I read it in Scientific American quite some time back, and it stuck in my head. Searching... here, I think this is the one:

The Origin of Life On Earth; October 1994; by Orgel; 8 Page(s) Growing evidence supports the idea that the emergence of catalytic RNA was a crucial early step. How that RNA came into being remains unknown.

The issue itself is filed away somewhere in a box that will take me a lot of work to dig out, so unless you don't have access to a local copy I'd prefer not to. The article might have a reference to a better paper than a scientific american article, hopefully. Bryan

[edit] =

Wow! Great stuff! Thanx for an article that broadens my universe!

I was immediately inspired to revise my family tree. There are now 3 nodes at the root: The PNA World, The RNA World, and Biota (or should it be Eubiota?) The first two items are flagged "hypothetical", "extinct" and "supposed precursors of all Biota".

Critiques: The technicalities are simply too overwhelming for the general reader. I won't comprehend the structure in the 1st paragraph without a diagram. Shouldn't it be a goal to present all molecular structures both as diagrammed formulas and as objects rotating in a reader-controlled panorama? (The technology exists, I think, but the work here is daunting.)

The 1st sentence in the 2nd paragraph is fine, but the rest of this 'graph is incomprehensible to a general reader (the sin of unexplained jargon). Wouldn't it be enough, comparing reactivity and stability, to say, for example, that double helix DNA comes apart at temperatures 20 Celsius lower than double chain PNA?

Are there such things as PNA catalysts (analogous to enzymes and ribozymes)? This would be of great significance for evolution.

If the PNA and RNA Worlds existed simultaneously, it is clear that PNA's lower reactivity and greater stability would allow the RNA World to gobble it up.

Could one say [gasp:anthropomorphic] that RNA still rules today, using DNA as a convenient, slowly mutating, copyable information store? If there were CPUs in the cell, would they be ribozymes? I see the ribosomes and some of the other things as distributed processors.

  Solo Owl 01:42 Nov 4, 2002 (UTC)

[edit] PNAs as progenitors

It is true that some researchers have proposed that PNAs were progenitor molecules, but I don't think anyone actually takes that claim seriously. There is absolutely no evidence that PNAs ever existed outside of the lab, unlike RNA for which many natural ribozymes are known.