Analysis of DNA from related and diverse species of Barley

Abstract

DNAs of three closely related diploid species Hordeum vulgare, H. agriocrithon and H. spontaneum were compared among themselves and with a group of three species related to each other H. californicum (2x), H. jubatum (4x), and H. arizonicum (6x) having one genome in common. Buoyant densities of the DNAs from these species fall within a narrow range (1.700-1.701 g cm^-3). Melting temperatures (T_m) of the DNAs are also similar (85.2-86.2°C). None of the DNAs showed any satellite band in neutral Cesium chloride gradients. In silver-cesium sulphate gradients, however, DNAs of all the species formed satellites on both the light and heavy sides of the main. band The diploid series have similar but not identical satellite patterns. The members of the polyploid series showed similar satellite patterns among themselves but distinct from those of the diploid series. In the polyploid group the amount of satellite showed a progressive decrease with the increase in the ploidy. The amount of repeated DNA (reassociating up to Cot 100) in H. vulgare was 69% and in H. arizonicum 65% of the total. The two species differed in their Cot curves. The low Cot fractions of H. arizonicum contained components of low buoyant densities which were absent in the corresponding Cot fractions of H. vulgare DNA.