Study of a haploid yeast strain with an unusually high rDNA content. II. Fractionation of the DNA in preparative Ag+-Cs2SO4 density gradients.

Yeast DNA has been fractionated in preparative Ag+-C-S2SO4 density gradients. After complexing with silver ions at a pH of about 7, the rDNA appears in a defined heavy satellite component in the gradient. For our particular strain, the satellite represents about 15% of the total nuclear DNA and has been identified as the gamma-DNA. In alkaline CsCl density gradients, the satellite DNA forms two bands, of which the light component hybridizes with ribosomal RNA.