The dawn of the RNA World: toward functional complexity through ligation of random RNA oligomers.
A main unsolved problem in the RNA World scenario for the origin of life is how a template-dependent RNA polymerase ribozyme emerged from short RNA oligomers obtained by random polymerization on mineral surfaces. A number of computational studies have shown that the structural repertoire yielded by that process is dominated by topologically simple structures, notably hairpin-like ones. A fraction of these could display RNA ligase activity and catalyze the assembly of larger, eventually functional RNA molecules retaining their previous modular structure: molecular complexity increases but template replication is absent. This allows us to build up a stepwise model of ligation-based, modular evolution that could pave the way to the emergence of a ribozyme with RNA replicase activity, step at which information-driven Darwinian evolution would be triggered.
Briones
Carlos
C
Centro de Astrobiología (CSIC-INTA), 28850 Torrejón de Ardoz, Madrid, Spain. brioneslc@inta.es
Stich
Michael
M
Manrubia
Susanna C
SC