An international team has engineered enzymes capable of replicating nucleic acid polymers that are made of non-natural nucleotides.1 Despite general media reports that the findings are a breakthrough on the way to artificial life, the practical utility of the technology is in generating new types of aptamers.
Aptamers are small nucleic acid oligomers selected for high-affinity binding to specific protein or nucleic acid targets. To find an aptamer that hits a given target, researchers perform a recursive in vitro selection procedure called systematic evolution of ligands by exponential enrichment (SELEX). In SELEX, aptamers that bind their targets are purified and replicated by polymerases, and then the cycle is repeated. After many such