Isolation of Friend leukemia virus resistant line from non-inbred mouse colony.

Among a non-inbred ddY mouse colony, a small portion showed marked resistance to splenomegaly induction by Friend leukemia virus (FLV). The resistance to the virus appears to be governed by a single gene, and is dominant over the susceptibility. Thus, it was possible to breed two lines of mice, which are respectively resistant and susceptible to the virus. Resistant response to FLV of the resulting mice, which seemed to be homozygous for the dominant resistant gene, is similar to that of C57BL/6 and more rigid than that of BALB/c mice. Phenotype of F1, segregation ratio in F2 and BC1 hybrid progeny between resistant and susceptible lines were also compatible with the single gene model.