title: Evolution of structure in RNA.
abstract: Evidence is presented that structures formed by RNA and by RNA in association with protein have evolved from simpler structures by successive unions among them. The progressively more complex molecular structures have conferred selective advantage in evolution by progressively enhancing the specificities of the biochemical reactions. Before each union, the RNAs which joined at the time of union belonged to separate reproducing species. The record of unions in RNA therefore reflects unions among species in the biosphere, tracing the evolution of life from quite simple reproducing molecules up to well developed organisms.
mesh_terms: D005075:Biological Evolution; D005796:Genes; D006860:Hydrogen Bonding; D009690:Nucleic Acid Conformation; D011108:Polymers; D011506:Proteins / Q000378:metabolism; D012313:RNA / Q000235:genetics; D012335:RNA, Ribosomal / Q000096:biosynthesis; D012343:RNA, Transfer / Q000096:biosynthesis; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism
chemical_list: D011108:Polymers; D011506:Proteins; D012335:RNA, Ribosomal; D012346:RNA, Transfer, Amino Acyl; D012313:RNA; D012343:RNA, Transfer