[Features of replicating synthetic oligonucleotides with non-native chains].

The in vitro replication of synthetic oligodeoxyribonucleotides carrying internucleotide polyphosphate groups or alkanediol "spacers" of various sizes with the use of various DNA polymerases has been studied. All modifications, except for the diphosphate group, almost completely block the polymerization process. In the case of AMV reverse transcriptase, Taq and T7 DNA polymerases and also the Klenow fragment of E. coli DNA polymerase I, a template-independent addition of a nucleotide at the 3' end of the incomplete replica was observed. T4 DNA polymerase, displaying the strongest 3'-5' exonuclease activity among the polymerases studied, did not incorporate additional nucleotides. The use of oligonucleotides with non-nucleotide inserts as primers in polymerase chain reaction (PCR) allows to obtain DNA copies with protruding 5'-termini, suitable for hybridisation analysis.