mutants of bacteriophage phie inducing only 1 to 5 % of wild-type levels of dttp-dutp nucleotidohydrolase give normal bursts of viable progeny phage whose dna contains 5 to 10 % thymine ( but no uracil ) in place of 5-hydroxymethyluracil .
C0040087
thymine
C0041917
uracil