Molecular State in Somatic Hybrids among Gramineous and Leguminous Species

Abstract

Analysis of organelle DNAs by the restriction enzymeinduced fragment pattern and Southern blotting were carried out on interfamilial and intergeneric somatic hybrids or hybrid calli among a gramineous species, rice, and three leguminous species, soybean, alfalfa and birdsfoot trefoil. In the cases of interfamilial hybrids, spontaneous chromosome elimination of rice occurred, and species specific DNA fragments of both species, and novel DNA fragments, which did not appear in either species, were found in mitochondrial DNAs (mtDNAs). This suggests that these hybrids have mtDNAs of both species or recombinant mtDNA. On the other hand, only the chloroplast DNAs (cpDNAs) of leguminous species remained in most cases. In the cases of intergeneric hybridization, the somatic hybrids were symmetric or asymmetric. The latter were induced by X-rays. The behavior of mtDNA was almost as complicated as that of mtDNA in interfamilial hybrids, while those of cpDNA were comparatively simple.