title: Analysis of plant genomes. III. Denaturation and reassociation properties of cryptic satellite DNAs in barley (Hordeum vulgare) and wheat (Triticum aestivum).
abstract: A cryptic satellite fraction was isolated from barley and wheat by preparatory ultracentrifugation of total DNA in Ag+-Cs2SO4 density gradients and was characterized by studying its denaturation-reassociation properties. Wheat satellite DNA underwent thermal denaturation as a single component with a Tm of 81 degrees C while barley satellite DNA consisted of one major (Tm = 82.5 degrees C) and one minor (Tm = 91 degrees C) component. When the barley and wheat satellites were reassociated and then melted, the Tm values were found to be 6--7 degrees C lower than those of the corresponding native DNA preparations. Examination of the C0t curves of these two satellite DNAs revealed the presence of a major, fast reassociating and a minor, slow reassociating fraction. The fast reassociating DNA fraction of barley was found to have a complexity of 9.7 . 10(5) daltons while that of wheat satellite was 5.8 . 10(5) daltons. Since these satellites reassociated with about 4--5% base mismatching, as judged by their deltsTm (6--7 degrees C), they each appear to consist of rather similar base sequences.
mesh_terms: D002499:Centrifugation, Density Gradient; D004247:DNA / Q000235:genetics; D004276:DNA, Satellite / Q000235:genetics; D001467:Hordeum / Q000235:genetics; D007700:Kinetics; D009691:Nucleic Acid Denaturation; D009695:Nucleic Acid Renaturation; D012639:Seeds; D013696:Temperature; D014908:Triticum / Q000235:genetics
chemical_list: D004276:DNA, Satellite; D004247:DNA