[Phage T4 partial diploids obtained with the method of DNA interrupted injection. II. The mapping technique based on the physical size measurement of the diploid region].

Populations of the E. coli B mixedly infected with the whole chromosome of the amber mutant in respect to two genes under consideration and with a chromosome fragment of the phage T4 "wild" type are examined. The fragment length with which both of the amber mutants defect functions are compensated is determined to measure physical distance between the genes. Distances so obtained do not depend on recombination frequencies and are shown to be additive and "complementary". The latter property means that the sum of the smaller and "complementary", larger distances between two genes on the circular map equals the complete linkage group quantity. Moreover, a "complementary", larger distance is measured directly and independently on a smaller one, whereas current mapping technique fail to do so. The method enables to evaluate a size of rather long phage T4 gene region, for example gene 43, i. e. the structural DNA polymerase gene. Phage T4 genes 34 and 35 are shown to have a common start region for transcription and translation, i. e. they belong to the same operon. In consequences the circular map of physical distances between phage T4 genes is constructed.