
Mimicking an impact on Earth’s early atmosphere yields all 4 RNA bases - BerislavLopac
https://arstechnica.com/science/2017/04/mimicking-an-impact-on-earths-early-atmosphere-yields-all-4-rna-bases/
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moh_maya
Ribonucleotides are very very very reactive / unstable - definitely in today's
atmosphere / world, and likely even in a neutral / reducing abiotic world.
(almost every surface we touch today will be left with very robust RNAses, for
instance, which makes working with RNA a particularly fun experience in lab..,
but I digress).

I am struggling to imagine a clear path from ribonucleotide synthesis during
an atmospheric impact to polymerization (which again requires protected /
specific conditions), to the point where the randomly assembled RNA polymerase
has catalytic activity, and specifically, ability to self replicate.

I recognize that the article is not claiming the nucleotides can polymerize,
etc. Still, I fail to see how enough nucleotides could be created through such
processes and remain stable through their descent to the surface to form
polymers / ribozymes.

I understand that these are probabilistic events, so a low probability event
is still possible.

However, my contention is that atmospheric synthesis of ribonucleotides,
followed by polymerization into a catalytically active RNA polymer (which is
equally unstable) which then has to have a readily accessible pool of mono-
nucleotides or peptides / amino acids to act on, all during high atmospheric
impact / subsequent descent to the surface, seems, well, challenging to
envision.

So, to summarise, I think this is a cool result, but I don't think it moves us
forward much in terms of understanding how life got started. And I speak as an
advocate of the RNA world hypothesis.

~~~
dekhn
I don't see any likelihood of RNA polymers forming during the impact. Just
monomers. The monomers themselves are fairly stable in dry, cool locations.

Presumably said monomers are synthesized in the blast, land somewhere that
favors polymerization without too many of them being degraded (glycosidic bond
breakage, modified base or sugar). And presumbly that location is moist with
high surface area and a thermal cycle, say porous rock near a hydrothermal
vent.

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loa_in_
Let's fire PALS at TRAPPIST planets, so we don't get disappointed as to
whethher we find life there.

