SELF REPLICATION OF COMPLEMENTARY NUCLEOTIDE-BASED OLIGOMERS

THE development of non-enzymatic self-replicating systems based on aut ocatalytic template-directed reactions is a current objective of bioor ganic chemistry(1-6). Typically, a self-complementary template molecul e AB is synthesized autocatalytically from two complementary template fragments A and B7-16. Natural replication of nucleic acids, however, utilizes complementary rather than self-complementary strands. Here we report on a minimal implementation of this type of replication(17) ba sed on cross-catalytic template-directed syntheses of hexadeoxynucleot ide derivatives from amino-trideoxynucleotides. In our experiments, tw o self-complementary and two complementary templates compete for their combinatorial synthesis from four common trimeric precursors. We prov ide kinetic evidence that cross-catalytic self-replication of compleme ntary templates can proceed with an efficiency similar to that of auto catalytic self-replication of self-complementary templates. We observe selective stimulation of template synthesis, and thus information tra nsfer, on seeding the reaction mixtures with one of four chemically la belled templates bearing the sequence of the reaction products. Our re sults bring a stage closer the development of schemes that might expla in how replicating systems based on nucleic acids arose on the prebiot ic Earth.