A suitable method for construction and cloning hybrid plasmids containingEcoRI-fragments ofE. coli genome

Abstract
A convenient procedure for the isolation of specificEcoRI-fragments ofE. coli genome and their amplification on Km-resistance plasmid vector CK Δ11 is described. The hybrid molecules were constructedin vitro usingEcoRI-digestion, followed by ligation. Then appropriatedE. coli strain was transformed with ligated DNA mixture and hybrid plasmids CK Δ11-arg +, CK Δ11-his +, CK Δ11-thr + and CK δ11-leu + containing loci ofE. coli genome were selected by molecular cloning. The hybrid plasmids obtained consisted of oneEcoRI-fragment of initial plasmid CK Δ11 and one respective specific portion ofE. coli genome.