RESTRICTION MAPPING OF PHAGE-LAMBDA VECTORS USING NONRADIOACTIVE METHODS

In order to take advantage of non-radioactive methods, we have develop ed two plasmids (p lambda LE and p lambda RE) for mapping restriction sites of long inserts cloned in phage lambda vectors. These plasmids a re constructed by cloning the left 402-bp and right 560-bp phage lambd a genome ends, respectively. To map restriction sites, the cloned sequ ences in p lambda LE and p lambda RE are labeled with digoxygenin and hybridized to partially digested lambda DNA. The ladder of bands detec ted with these probes can be used to construct restriction maps in the same way as those obtained using radioactively labeled cos complement ary oligodeoxyribonucleotides [Rackwitz et al., Gene 30 (1984) 195-200 ].