Replicating lipid micelles: a feasible precursor to the origin of life and the earliest appearance of genomes.
The most commonly accepted scenario of early Earth includes: creation of the universe around 13.8 Ga (Giga-annus; or 109 years ago); establishment of our solar system ~ 4.60 Ga; and formation of Earth ~ 4.54 Ga. The earliest life forms on our planet so far observed to have existed, are microbes that left signals of their presence in rocks ~ 3.6 Ga - suggesting that Life forms existed within the first 940 million years after Earth's formation. However, an intriguing recent publication [1] infers that the last universal common ancestor (LUCA) likely existed by 4.2 Ga, and that the inferred LUCA had a genome of at least 2.5 Mb of DNA, encoding around 2,600 proteins; this suggests that sophisticated Life might have existed within the first 340 million years after Earth was formed. The commonly accepted geological history of early Earth suggests that the turbulent Hadean Eon lasted until 4.0 Ga, with the Late Heavy Bombardment (LHB) period occurring around 4.1 to 3.8 Ga. If Earth during the Hadean exhibited a molten surface, intense volcanic activity, and constant bombardment by asteroids and comets - how were sensitive molecules (e.g., nucleic acids, proteins) able to survive? Considering the "Lipid First" hypothesis [2], we propose that replicating lipid micelles are feasible candidates for having populated much of Earth's deep hydrothermal vents and turbulent surface within the first 340 million years of Earth's existence. These lipid micelles could therefore have provided a plausible form of "protective capsules" inside which early Life's sensitive molecules were able to evolve.