Variety of Endogenous Proviruses in the Genomes of Chickens of Different Breeds

Abstract
Pencillium stoloniferum virus S has been fractionated into four particle classes, E, M, L and H, with sedimentation coefficients of 66, 87, 101 and 113 S, respectively. E particles were shown to be empty capsids, while M particles contained single-stranded RNA, L particles contained double-stranded RNA, and H particles contained both single-stranded RNA and double-stranded RNA. The mol. wt. of L particles was found from sedimentation and diffusion coefficients to be 6.0 × 106.