Electrophoretic separation in a 5% polyacrylamide slab gel of dsRNA from white clover cryptic viruses 1 (A), 1 and 2 (B), 2 alone (C), maize rough dwarf virus (D) and cytoplasmic polyhedrosis virus (E) (gift of C. C. Payne; photo courtesy of G. Boccardo). Stained with silver. In addition to the two more rapidly migrating bands of white clover cryptic virus 2 RNA, lane C also contains two slowly migrating bands, sometimes present in extracts of virus particle preparations still contaminated with host materials (Boccardo et al., 1987).