The Prequel of the “RNA World”, A Hypothetical Homochiral Selective Mechanism for D- RNA Monomer Survival in Primitive Earth Environmental Conditions

Chirality is a widespread phenomenon across the universe. In living systems, homochirality is one of the fundamental characteristics of biomolecules—for instance, all nucleotides constituting DNA and RNA are of the D-form. Under the primordial physicochemical conditions on Earth, any chiral molecules produced would have existed primarily as racemic mixtures. Therefore, how a homochiral biomolecular system was established during the origin of life remains a critical question that awaits further investigation and validation. The “RNA World” theory posits that RNA played a decisive role in the early stages of life’s evolution, given its dual capacity for information storage and organic catalysis. Drawing upon existing theories of biological evolution—including ultraviolet light stressing, diurnal temperature variations, and protocell evolution—this study proposes a novel hypothesis: in the early stages of life’s evolution, DNA assumed a unique role—assisting RNA monomers in achieving homochiral survival selection.