Single-gene abrogation of spontaneous pleomorphic SJL/J mouse reticulum cell sarcoma expression.

Inbred SJL/J and A.SW/SnJ mice have been bred to produce (SJL female X A.SW male)F1 and A.SW female X SJL male)F1 mice. F1 mice were then crossed to produce (SJL female X A.SW male)F2 and (A.SW female X SJL male)F2 mice. The inbred, F1, and F2 populations were followed for 2 years to determine the incidences of spontaneous reticulum and sarcoma (RCS) expression. SJL mice had a greater than 90% incidence of RCS, although F1 mice showed almost no RCS. The incidence of RCS in the F2 populations was 24.1%. These data were consistent with the hypothesis that in F1 and F2 populations a single dominant A.SW gene is able to suppress the expression of the pleomorphic RCS disease characteristic of the SJL mouse. This gene was not an H-2 gene, since the two strains were congenic with respect to the major histocompatibility complex; this gene was not on the Y-chromosome, and its phenotypic expression was not inherited in an X-linked manner.