TABLE 2.

Phages harboring recombination substrates^a

Phage	oripACYC184	Chi at A	Chi at B
λZS820	0	0	0
λRF949	+	0	+
λRF950	+	+	0
λRF951	+	+	+
λRF953	0	+	+

^aEach Chi site in the schematic representation of the cloned intramolecular recombination substrate consists of three Chi octamers (6). The approximate locations of ori_pACYC184, the Kan^r gene, and Chi insertion sites (A and B) are indicated.