Analysis and in situ hybridization of cryptic satellites in Hordeum arizonicum

Three satellites, one (H1) on the heavy side of the main band of Hordeum arizonicum DNA and two (L1, L2) on the lighter side were purified using preparative silver-cesium sulphate density gradients. The native and the reassociated satellite DNAs were analysed in terms of buoyant densities and thermal dissociation. In cesium chloride gradients the H1 and L1 satellites formed single peaks corresponding to buoyant densities of 1.700 and 1.701 g · cm(-3) respectively while the L2 satellite gave two peaks (1.680 and 1.661 g · cm(-3)). The H1 satellite showed three thermal components (Tm=82.5 °C, 87 °C and 91.5 °C) while the L1 and L2 had three (86.5, 92, 97.5 °C) and two (86, 95 °C) respectively. The H1 satellite was localized on the nuclei and chromosomes. The distribution of H1 onto approximately on third of the complement may reflect the genome specific origin of this satellite.