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Double Infection, Recombination, and Segregation of Two R Factors, R 100 and R ts 1, and Their Possible Bearing on the Genetic Structure of R 100
Author(s) -
Yoshikawa Masanosuke,
Sakai Katsuko
Publication year - 1972
Publication title -
japanese journal of microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0021-5139
DOI - 10.1111/j.1348-0421.1972.tb00621.x
Subject(s) - gene , genetics , recombination , biology
Applying the observation by Yokota et al (1969) that a cell doubly harboring an R factor (R100) and a temperature sensitive R factor (R ts 1) produces segregant R factors with various resistance patterns, a total of 271 segregant R factors were obtained. There were 163 resistant to ( sul, str, kan ), 39 resistant to ( sul, str, cml, kan ), 62 resistant to ( sul, str, tet, kan ) and finally 7 resistant to ( tet, kan ). More than 90% of the former 3 segregants were fi + and the remainder, including all of the ( tet, kan ) segregants, were fi − . Some fi − segregants with the former 3 resistance patterns and all of the ( tet, kan ) segregants were nontransmissible. All of these segregants were still temperature sensitive. Based upon the results of three experiments; (a) the growth at 43 C to observe linked loss of the kan gene and the genes derived from R 100, (b) a conjugal analysis of the relevant resistant markers, and (c) a transductional analysis of these same markers, several conclusions were made. The 2 R factors both consisting of a circle were supposed to have recombined to form a larger circle which then further resulted in the final formation of smaller circles. The possible bearing of these observations and conclusions on the genetic structure of R 100 was discussed.