Gene Recombination in the Bacterium Escherichia coli

The study of inheritance in bacteria has, for the most part, been confined to the investigation. of mutational changes in the course of clonal reproduction. With the exception of experiments on pneumococcus type transformations there have been few studies on the direct hereditary interaction of one bacterial type with another. The conception that bacteria have no sexual mode of reproduction is widely entertained. This paper will be devoted to the presentation of evidence for the occurrence in a bacterium of a process of gene recombination, from which the existence of a sexual stage may be inferred. On the basis of mutation studies many investigators have concluded that the hereditary properties of bacteria are based on the existence of genes (Luria and Delbruck, 1943; Roepke et al., 1944; Lwoff, 1941; Demerec and Fano, 1945; Gray and Tatum, 1944), although it is not clear whether these genes should be homologized with the Mendelian factors of higher organisms, or with the extra-nuclear factors which have been demonstrated in some microorganisms and higher plants (Sonneborn, 1943; Spiegelman et al., 1945; Rhoades, 1943).