Researchers have uncovered a crucial clue about the emergence of life on Earth by investigating the impact of high-energy ultraviolet light on early DNA. A team led by biophysicist Christof Mast simulated how different components of the genetic code developed over time, considering various factors such as amino acid availability and meteorite hits.
To navigate the lack of concrete data from ancient environments, Mast’s team focused on developing codon chronologies – timelines mapping out the order in which DNA sequences most likely emerged. By hypothesizing the influence of UV radiation, scientists proposed more than 50 different chronologies.
The researchers fed experimental data about short DNA sequences into a computer model and extrapolated the results to simulate UV damage on longer and more realistic early genomes, known as protogenomes. Their findings suggest that UV-susceptible codons likely decomposed rapidly under early Earth conditions, with first genomes biased toward UV-resistant sequences.
The team’s proposal for a new codon chronology has sparked debate among researchers. While some are unpersuaded by the assumption of sequential codon emergence, others, like evolutionary biologist Joanna Masel, see potential in exploring UV radiation as a selection pressure on RNA molecules.
Mast’s team plans to expand their approach to calculate the UV dependency of RNA protogenomes, which could help predict UV damage on certain ribosomes. This next step aims to shed more light on the early genetic molecule and its connection to prebiotic chemistry.
Source: https://cen.acs.org/biological-chemistry/origins-of-life/Shining-light-origin-life/103/web/2025/02