A NEW BACTERIOPHAGE P1-DERIVED VECTOR FOR THE PROPAGATION OF LARGE HUMAN DNA FRAGMENTS

We have designed a P1 vector (pCYPAC-1) for the introduction of recomb inant DNA into E coli using electroporation procedures. The new clonin g system, P1-derived arteficial chromosomes (PACs), was used to establ ish an initial 15,000 clone library with an average insert size of 130 -150 kilobase pairs (kb). No chimaerism has been observed in 34 clones , by fluorescence in situ hybridization. Similarly, no insert instabil ity has been observed after extended culturing, for 20 clones. We conc lude that the PAC cloning system will be useful in the mapping and det ailed analysis of complex genomes.