Table 3.

RecD inhibits recombination in the recB^D1080A mutant

rec alleles*	Hfr recombination (%His+ [Strr])†		Phage λ recombination (% J+R+)‡		Chi activity§
	Mean	Range	Mean	Range	Mean	Range
None	0.001	0.0009–0.001	0.6	0.5–0.8	1.1	0.9–1.3
recBCD	1.4	0.9–1.8	4.5	4.1–5.1	6.0	5.9–6.1
recBC	0.8	0.7–0.9	4.9	4.8–5.3	0.9	0.7–1.1
recBD1080ACD	0.005	0.004–0.007	0.9	0.8–1.1	1.0	0.7–1.2
recBD1080AC	0.9	0.6–1.1	5.2	4.8–5.8	0.9	0.8–1.0

^*Strains are transformants of strain V67 with the indicated rec alleles present on derivatives of pACYC184. 

^† The number of His⁺ (Str^R) recombinants per Hfr donor cell, corrected for the viability of the recipient. The mean and range are shown for three independent matings in which 75–600 His⁺ colonies were counted for each determination. For each recipient, the frequency of F' his⁺ transfer from V156 (33) was 0.12–0.24. 

^‡ The frequency of J⁺R⁺ recombinants in cross lysates of phages 1081 and 1082 or 1083 and 1084 (33, 45) was determined by plating on strain 594 (sup⁺) for recombinants and on strain C600 (supE) for total phage titer. The mean and range of the frequencies are reported for three independent crosses. 

^§ The Chi activity for each set of crosses (phage 1081 × 1082 and 1083 × 1084) was determined as described (33). Chi activity = where (t/c) is the ratio of turbid to clear plaques from cross 1 (phage 1081 × phage 1082) or cross 2 (phage 1083 × 1084) among J⁺R⁺ recombinants.