1-3 molecules per cell
||Bacteria Escherichia coli
||X. Sunney Xie, Paul J. Choi, Gene-Wei Li, Nam Ki Lee, and Giuseppe Lia, 'Single-Molecule Approach to Molecular Biology in Living Bacterial Cells', Annu. Rev. Biophys. 2008. 37:p.419PubMed ID18573089
||Frame R, Bishop JO. 1971. The number of sex-factors per chromosome in Escherichia coli. Biochem. J. 121:93–103PubMed ID4940379
||Hybridizing RNA which was synthesized in vitro with DNA extracted from E. coli carrying F'8 gal.
||F'8 gal=A substituted sex-factor of Escherichia coli.