Abstract
The RNA world hypothesis of origin of life confers a central role to RNA molecules in information encoding and catalysis. Nevertheless, the transition from an RNA world to a world where heritable genetic information is encoded in DNA remains an open question. Recent experiments show that both RNA and DNA templates can extend complementary primers using free RNA/DNA nucleotides. Guided by these experiments, we analyse protocellular evolution with an expanded set of reaction pathways made possible through the presence of DNA nucleotides. By encapsulating these reactions inside three different types of protocellular compartments, each subject to distinct modes of selection, we show how protocells containing replicaseencoded DNA in low copy numbers and replicases in high copy numbers can dominate the population. Our work suggests a plausible pathway for the transition from an RNA world to a mixed RNA-DNA world characterized by Darwinian evolution, where DNA sequences encode heritable phenotypes.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
↵⋆ supratim.sen{at}iiserkol.ac.in
Main text: Few changes have been made to the Introduction. Some changes have been made in the Methods section for better clarity of our model. Figure-1 have been edited and a new figure (currently Figure-2) have been added for better clarity. An extra paragraph have been added to the Conclusion section. Supplementary information: A new section and a new figure have been added. Explicit reaction rates of different primer extension processes have been added for convenience.