by insertion of a dna fragment , containing the phage lambda pr promoter and the pm-promoted ci857 allele of the lambda repressor gene , in plasmid r1 upstream of the replication control genes , cloning vectors have been constructed which are present in one copy per chromosome at temperatures below 37 degrees c , and which display uncontrolled replication at 42 degrees c .
C0012854
dna
C0598312
replication