Analysis and in situ hybridization of cryptic satellites in Hordeum arizonicum

Abstract

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.