Two Naturally Occurring Transposons Indistinguishable from Tn7

Abstract
Two plasmids from different sources [Escherichia coli and Proteus mirabilis], determining trimethoprim and streptomycin resistances, harbor transposons which were designated as Tn71 and Tn72. These transposons are indistinguishable from Tn7 in the resistances determined, in their molecular masses and in the number and relative positions of their sites susceptible to the restriction enzymes EcoRI, HindIII and BamHI. Apparently, Tn7 was naturally spread among plasmids.