IS LIGATION THE ONLY SOLUTION TO THE PYROPHOSPHATE PROBLEM

Pyrophosphate linkages are easily formed during the nonenzymatic oligo merization of activated nucleotides. They often form 'caps' which term inate an oligonucleotide with a 5'-5' pyrophosphate. Owing to their st ructural resemblance to the intermediates in enzymatic ligation reacti ons, it has been suggested that pyrophosphate caps might have been cap able of acting as activating groups in chain elongation processes. We argue that an alternative possibility would have been the specific hyd rolysis of pyrophosphates.