Abstract

In Person

Prebiotic chemistry these days on Earth operates on two different metaphorical “worlds”. On one, leading with the elegant work of the Sutherland, Simons, and Leverhulme teams, the focus is on surface photochemistry of molecules arising from hazy reduced atmospheres, in particular, those where nitrogen is at the oxidation level of ammonia. It has not (yet) produced a single molecule of RNA , the (proposed) informational molecule that (purportedly) initiated Darwinian evolution.

In this talk, a visitor from the other world will show how oligomeric RNA with 3’,5’-linkages 150 ± 50 nucleotides long forms as the natural outcome of “privileged” chemistry beneath redox neutral atmospheres that are transiently reduced by Vesta-to-Ceres sized impactors. On Earth, this most likely happened 4.30 ± 0.05 billion years ago.

This RNA is long enough, and stereoregular enough, to have provided catalysts to support an “RNA World”. This World invented protein translation 4.20 ±0.11 billion years ago (based on arguable molecular clocks), and was sufficiently widespread to have left isotope enriched carbon entrapped in zircons dated at 4.10 billion years ago.

The production of pentoses (like ribose, ~100 kg/km2 per year ) cannot NOT happen on such worlds, if covered by basalts that deliver borate and condensed polyphosphates. Borate and condensed polyphosphate likewise privilege post-impact steps that yield ribonucleosides, ribonucleotides, and RNA .