RT Journal Article SR Electronic(1) A1 Okker, R. J. H. A1 de Groot, B.YR 1978 T1 Specificity of Partial Exclusion of Bacteriophage T2 in Crosses with T4 JF Journal of General Virology, VO 40 IS 3 SP 705 OP 709 DO https://doi.org/10.1099/0022-1317-40-3-705 PB Microbiology Society, SN 1465-2099, AB Summary An attempt was made to isolate a bacteriophage T4 mutant generally disturbed in its ability to exclude the localized exclusion sensitivity determinants of T2 from the progeny of crosses. The method used was a modification of that used previously, which revealed T4 mutants unable to exclude more than one of the T2 sensitive sites specifically. One out of 1000 isolates from a mutagenized T4 am56:am32 stock was found to be mutated in its exclusion properties. However, the mutant was not generally exclusion deficient. Its properties were similar to those of a double mutant T4 ex56:ex32, specifically unable to exclude the T2 sensitive sites near gene 56 and gene 32. The failure to isolate a generally excluding mutant at a frequency down to 10−3 renders the occurrence of a general exclusion locus unlikely., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-40-3-705