Abstract
Several F' agents which carry various sizes and different kinds of chromosomal segment have been isolated. These are infective and can determine certain male type of behavior by controlling the oriented transfer of the host chromosome. The F' agent can also pick up genes of the host cell and can exchange these genes with host cell chromosome. This agent has high contagiousness and can multiply faster than the host cell. Cells carrying F' can be cured with acridine treatment. Some F' agents carry chromosomal markers which are transduced when F' infects another cell.
The transductants form stable heterogenotes. Complementing pairs of mutant markers have given the wild type on segregation. Thus segregation, due to crossing over between the chromosome and the chromosomal fragment of F', occurrs within the heterogenote. F' transduces the exogenotic gene with higher frequency than the endogenotic gene. The episomic state of F' can be controlled with Rfd3.
The process of F-duction is quite like as mating process of Hfr.
A hypothesis on the structure of F' and the mechanism of determination of maleness by F' is discussed.
