this exogenous uridine radioactivity observed in the dna represented neither a dna-rna hybrid , rna primer pieces in dna synthesis , nor any other rnase-sensitive species , but was apparently the consequence of amination and methylation of the tritium-labeled uracil moiety to satisfy the metabolic needs of the replicating cells for cytosine and thymine bases .
C0012854
dna
C0000702
a