DNA of noninfectious and infectious integrated spleen necrosis virus (SNV) is colinear with unintegrated SNV DNA and not grossly abnormal.

The cleavage sites of eight restriction endonucleases in linear spleen necrosis virus (SNV) DNA were mapped, and the map was oriented with respect to viral RNA. With the aid of this map, several structural features of the viral DNA were elucidated: unintegrated linear SNV DNA is terminally redundant; the majority of SNV DNA molecules integrated in chicken DNA, which were previously shown to be present in many sites in cellular DNA, are colinear with unintegrated viral DNA; no tandem integration of proviral molecules is detectable; and the majority of integrated SNV DNA molecules, including integrated SNV DNA molecules previously shown to be noninfectious, do not have an altered restriction enzyme digestion pattern.