Restriction cleavage maps of coliphages 186 and P2

Summary The restriction enzymes BamHI, BglII, EcoRI, HindIII, PstI, XbaI and XhoI have been used to cleave DNA isolated from the related coliphages P2 and 186 for analysis on 1% agarose gels. Three approaches were used to map the sites of cleavage: a) analysis dependent upon the existence of cohesive termini and availability of viable P2-186 hybrids; b) analysis of double digests and redigests of isolated fragments with a second enzyme and c) analysis of partial digests by transfer to nitrocellulose and hybridization with a single fragment. This last approach and the results obtained from it are detailed in a separate paper (Saint and Egan, 1979). The number of sites of each enzyme are as follows: a) 186, BamHI-7, BglII-1, EcoRI-3, HindIII-2, PstI-22, XbaI-0 and XhoI-1; b) P2, BamHI-3, BglII-2 EcoRI-3, HindIII-0, PstI-3, XbaI-1 and XhoI-0. All of these sites have been mapped with the exception of PstI for 186, where only the five sites in the right 35% (the control region) have been mapped.