Deletion of chromosomal markers in association with F-prime factor formation inEscherichia coliK12

Genetic donors of E. coli K12 harbour the sex factor (F) which may be in two states with respect to the circular chromosome of the bacterial cell. F + cells harbour F in the autonomous state, whilst Hfr strains carry it integrated in the chromosome. As a result of having the sex factor in the integrated state, Hfr donors are able to transfer the chromosome to recipient (F~) cells as an oriented linear structure, the orientation being determined by the site at which integration has occurred (Wollman, Jacob & Hayes, 1956;