Life on Earth may owe its existence to a versatile little molecule that busied itself assembling the first genetic material some 4 billion years ago. This idea was proposed several years ago, and biochemists have now demonstrated the prowess of such a molecular midwife at assembling DNA in the lab.
DNA, which contains the genetic information for making proteins, consists of two long strands of stacked chemical units—nucleotides—joined like rungs on a ladder.
Special enzymes carry out the assembly and replication of these molecules.