Deoxyribonucleic acid-deoxyribonucleic acid hybridization of R factors

A new method of estimating deoxyribonucleic acid homology is presented and used to measure the homology between bacterial plasmids of different compatibility groups. Deoxyribonucleic acid of the P-group plasmid RP1, originally isolated in Pseudomonas aeruginosa, has considerable (50%) homology with an N-group plasmid of the Enterobacteriaceae.