The Eicher (Ei) C57BL/6 subline was separated from the parental C57BL/6J in 1976 and has been maintained as a separate subline since. C57BL/6 is the most widely used inbred strain. It is commonly used as a general purpose strain and background strain for the generation of congenics carrying both spontaneous and induced mutations. Although this strain is refractory to many tumors, it is a permissive background for maximal expression of most mutations. C57BL/6J mice are used in a wide variety of research areas including cardiovascular biology, developmental biology, diabetes and obesity, genetics, immunology, neurobiology, and sensorineural research. C57BL/6J mice are also commonly used in the production of transgenic mice. Overall, C57BL/6 mice breed well, are long-lived, and have a low susceptibility to tumors.
This subline differs from C57BL/6J at one known locus, although there may be others that have not been identifed. C57BL/6JEiJ does not have a spontaneous deletion in nicotinamide nucleotide transhydrogenase (Nnt), but does have the n-Tr20m1J mutation.
