On the Origin of Information Dynamics in Early Life
We hypothesize that predictable variations in environmental conditions caused by night/day cycles created opportunities and hazards that initiated information dynamics central to life’s origin.
Increased daytime temperatures accelerated key chemical reactions but also caused the separation of double-stranded polynucleotides, leading to hydrolysis, particularly of single-stranded RNA. Daytime solar UV radiation promoted the synthesis of organic molecules but caused broad damage to protocell macromolecules.
We hypothesize that inter-related simultaneous adaptations to these hazards produced molecular dynamics necessary to store and use information. Self-replicating RNA heritably reduced the hydrolysis of single strands after separation during warmer daytime periods by promoting sequences that formed hairpin loops, generating precursors to transfer RNA (tRNA), and initiating tRNA-directed evolutionary dynamics.
Protocell survival during daytime promoted sequences in self-replicating RNA within protocells that formed RNA–peptide hybrids capable of scavenging UV-induced free radicals or catalyzing melanin synthesis from tyrosine. The RNA–peptide hybrids are precursors to ribosomes and the triplet codes for RNA-directed protein synthesis.
The protective effects of melanin production persist as melanosomes are found throughout the tree of life. Similarly, adaptations mitigating UV damage led to the replacement of Na+ by K+ as the dominant mobile cytoplasmic cation to promote diel vertical migration and selected for homochirality.
We conclude that information dynamics emerged in early life through adaptations to predictably fluctuating opportunities and hazards during night/day cycles, and its legacy remains observable in extant life.
A hypothetical sequence of events that would allow protocells to reduce the damage from UV light during daytime hours. A. Large negatively charged macromolecules confined to interior create charge gradient. B. Proton entry induces osmotic imbalance leading to water entry, swelling, and bursting. C. UV-driven pump extrudes H+ to prevent swelling, Na+/H+ exchanger extrudes Na+, causing K+ to influx. D. Heavier K+ ions cause sinking. E. Pump stops during nighttime, leading to Na+ reentry. F. Cycle repeats on daytime, providing mechanism to shield cell from harsh UV. — LIFE
On the Origin of Information Dynamics in Early Life, Life 2025, 15(2), 234; https://doi.org/10.3390/life15020234 (open access)
Astrobiology,
