Molecular and General Genetics MGG

, Volume 105, Issue 1, pp 1–15 | Cite as

Production of a merodiploid strain from a double male strain ofE. coli K12

  • A. J. Clark
  • W. K. Maas
  • B. Low


A double male strain ofE. coli K12 is capable of siring F′ progeny at a frequency approximately 103 to 105 times greater than that shown by normal Hfr strains. The F′ derivatives are merodiploid for approximately 30% of the standardE. coli map. The F′ element inherited by these progeny is called F20. Anomalies in the donor characteristics of the F′ progeny are explained by a description of the possible recombinant types in which markers heterozygous in the merodiploid strains are reassorted and by an analysis of the concept of the F′ strain. Characterization of the F′ progeny biochemically and morphologically is also discussed.


Donor Characteristic Recombinant Type Male Strain Merodiploid Strain 
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Copyright information

© Springer-Verlag 1969

Authors and Affiliations

  • A. J. Clark
    • 1
    • 2
  • W. K. Maas
    • 1
    • 2
  • B. Low
    • 1
    • 2
  1. 1.Department of Molecular BiologyUniversity of CaliforniaBerkeley
  2. 2.Department of MicrobiologyNew York University Medical SchoolNew York

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