Abstract
phiX RF DNA was cleaved by restriction enzymes from Haemophilus influenzae Rf (Hinf I) and Haemophilus haemolyticus (Hha. I). Twenty one fragments of approximately 25 to 730 base pairs were produced by Hinf I and seventeen fragments of approximately 40 to 1560 base pairs by Hha I. The order of these fragments has been established by digestion on Haemophilus awgyptius (Hae III) and Arthrobacter luteus (Alu I) endonuclease fragments of phiX RF with Hinf I and Hha1. By this method of reciprocal digestion a detailed cleavage map of phiX RF DNA was constructed, which includes also the previously determined Hind II, Hae III and Alu I cleavage maps of phiX 174 RF DNA (1, 2). Moreover, 28 conditional lethal mutants of bacteriophage phiX174 were placed in this map using the genetic fragment assay (3).