The transposons Tn 501 (Hg) and Tn 1721 (Tc) are related

Internal sequences of Tn 501 (Hg) and Tn 721 (Tc) have been compared by hybridization. In spite of the difference in the resistance they code for, there is extensive homology between the two elements. This homology resides in the transposon-coded genes that are necessary for transposition and indicates that the elements are closely related.