A supernumerary sex chromosome, symbolized by F, that determines the sex of E. coli. In the presence of the F episome, the bacterium functions as a male. F is a circular DNA molecule made up of about 94,000 base pairs, about 2.5% the amount in the E. coli chromosome. About one-third of the genes in the F chromosome are involved in the transfer of male genetic material to the female, including the production of the F-pilus, a hollow tube through which DNA is transferred during conjugation. See circular linkage map, F-prime factor, Hfr strain, MS2, pilus.
Subjects: Genetics and Genomics.