[Deletion of the phage lambda att80 Tn9 genome; the type of intramolecular recombination].

The intramolecular deletion-generating recombination which transforms lambda bacteriophage genomes into the plasmids (named pLS) proved to be site-specific to a certain extent. Using electron microscopy heteroduplex analysis three preferential sites for this recombination were found in seven independent pLS isolates studied. Att-sites were not registered to be involved in the formation of deletions in isolates studied. It was shown that recombination operating in our system was independent of the phage int and bacterial recA genes.