When Did Life Likely Emerge on Earth in an RNA‐First Process?. Issue 2 (24th September 2019)

• Record Type: Journal Article
• Authors: Benner, Steven A.; Bell, Elizabeth A.; Biondi, Elisa; Brasser, Ramon; Carell, Thomas; Kim, Hyo‐Joong; Mojzsis, Stephen J.; Omran, Arthur; Pasek, Matthew A.; Trail, Dustin
• Is Part Of: ChemSystemsChem. Volume 2:Issue 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-09-24
• Subjects: geochemistry -- origin of life -- oxidation -- prebiotic chemistry -- RNA world; Synthetic biology -- Periodicals; Artificial cells -- Periodicals; Chemical systems -- Periodicals; Biochemistry -- Periodicals; Biotechnology -- Periodicals; 572
• DOI: 10.1002/syst.201900035
• Languages: English
• ISSNs: 2570-4206

Abstract

Abstract: The widespread presence of ribonucleic acid (RNA) catalysts and cofactors in the Earth′s biosphere today suggests that RNA was the first biopolymer to support Darwinian evolution. However, most "path‐hypotheses" to generate building blocks for RNA require reduced nitrogen‐containing compounds not made in useful amounts in the CO2 −N2 −H2 O atmospheres of the Hadean. We review models for Earth′s impact history that invoke a single ∼10 23 kg impactor (Moneta) to account for measured amounts of platinum, gold, and other siderophilic ("iron‐loving") elements on the Earth and Moon. If it were the last sterilizing impactor, by reducing the atmosphere but not the mantle Moneta, would have opened a "window of opportunity" for RNA synthesis, a period when RNA precursors rained from the atmosphere onto land holding oxidized minerals that stabilize advanced RNA precursors and RNA. Surprisingly, this combination of physics, geology, and chemistry suggests a time when RNA formation was most probable, ∼120±100 million years after Moneta′s impact, or ∼4.36±0.1 billion years ago. Uncertainties in this time are driven by uncertainties in rates of productive atmosphere loss and amounts of sub‐aerial land. Abstract : Timing prebiotic RNA formation : Models for Earth′s impact history explain the late delivery of platinum, gold, and other siderophiles via a ∼10 23 kg impactor (Moneta) circa 4.48 billion years ago. The iron core from this impactor would have reduced the atmosphere above a relatively oxidized mantle, opening a window of opportunity for RNA precursor synthesis. Surprisingly, this suggests that RNA formation was most probable ∼4.36±0.1 billion years ago.