[Construction and use of phasmid vectors of large capacity]

lambda vector phages--pUC19 phasmid hybrids were constructed. The hybrids, phasmids lambda pMYF131 and lambda pSL51, were used as vector molecules for making genomic libraries. Vector phasmids exist as plasmids in vivo. They contain all the genes and specific sites necessary for lytic development, but the DNA molecules are not long enough to be packaged in lambda capsid. Elongation of the molecule due to insertion of a foreign DNA fragment renders phasmid all features of non-defective phage. Output of recombinants is up to 3 X 10(6) per 1 microgram of phasmid vector DNA. The fraction of non-recombinants in libraries is less than 1-0.1%. The capacity of the vectors is 19.6 and 22 kb for lambda pMYE131 and lambda pSL51 accordingly. It is possible to clone DNA fragments with blunt ends and various sticky-end fragments obtained by digestion with 14 prototype restrictases, into nine unique restriction sites of vector lambda pMYF131. The created vectors allowed to construct more than 30 representative genomic libraries of eukaryotic and prokaryotic organisms. 13 individual genes were identified within the libraries.