[Construction and study of a new type of phage lambda DNA vector molecule].

A group of lambda mutants (mutants lambda 0) harbouring lesser number of EcoRI restriction sites on DNA molecules was selected. lambda3-1 recombinant (genotype lambdab221amgamma210Sr1lambda3+c-Px) was created by crosses of lambda02 phage with other lambda mutants. This phage DNA may be used as a vector molecule which makes it possible to select easily phages harbouring insertions of EcoRI DNA fragments. The maximal size of DNA fragment, the insertion of which would not decrease lambda3-1 viability, is 7.7 megadaltone. Lambda3-1 DNA has three regions heterological to lambda DNA, two of which probably include sites SRIlambda4 and SRIlambda5 and some juxtaposed genes. For example, Ptgene of lambda phage in juxtaposition with site SRIlambda4 is substituted by Px gene on the lambda3-1 DNA molecule.