Definitive evidence that the murine C-type virus inducing locus Akv-1 is viral genetic material.

Abstract
DNA of the AKR mouse contains a set of murine leukemia virus sequences that are not present in DNA of the NIH Swiss mouse. NIH mice partially congenic for the AKR murine-leukemia-virus-inducing locus Akv-1 contain this set of sequences, and, in a three-point cross segregating for Akv-1 on an NIH background, the sequences segregated with Akv-1. It is concluded that the Akv-1 locus contains viral sequences.