Evolution: Narrowing the timeline for the RNA World (Nature Communications)

Conditions that could sustain a proposed early stage of life known as the RNA World may have stabilized around 4.33 billion years ago, according to a modelling study published in Nature Communications. The research proposes a timeline for when parts of Earth’s surface and shallow crust became cool enough for the building blocks of life to persist, potentially shedding further light on our understanding of Earth’s early biological history.

Before DNA became central to life, it is thought that RNA molecules may have stored genetic information and replicated themselves, a period of time known as the 'RNA World’. However, the young Earth was repeatedly heated by impacts from asteroids and other leftovers of planet formation creating a potentially inhospitable environment for prebiotic chemistry — the chemical processes that preceded life — to continue over long periods. Previous attempts to constrain a suitable period for the development of the RNA World have been inconclusive.

Oleg Abramov and colleagues used a three-dimensional computer model to simulate the thermal effects of impacts on Earth’s crust between 4.5 and 3.5 billion years ago. The model tracked temperatures in the upper crust along with the thermal stability limits of RNA and other life-relevant molecules, such as peptides, lipids, and nucleotides. The simulations suggest that frequent global sterilization events (such as the secondary deposition of hot rock fragments, melted material, and dust onto the surface) continued until approximately 4.4 billion years ago. These estimates indicate that it was unlikely that prebiotic chemical reactions could have happened on a sustained basis before this time. However, the model suggests that conditions after this point became milder, with energy-rich hydrothermal areas becoming more widespread. The authors identify a ‘sweet spot’ at approximately 4.33 billion years ago as the period with the strongest combined potential for persistent RNA-related chemistry. This is roughly 130 million years before the estimated emergence of the last universal common ancestor, which would suggest that life emerged relatively quickly once conditions became favourable.

The authors caution that the model is only able to assess thermal conditions present on Earth and cannot directly establish when life emerged. However, the proposed window remained broadly similar across the different bombardment scenarios assessed.

• Article
• Open access
• Published: 22 September 2026

Abramov, O., Medvegy, A., Kremer, B. et al. A Hadean timeline for the emergence of the RNA World. Nat Commun 17, 9790 (2026). https://doi.org/10.1038/s41467-026-76978-3
 

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