Mitochondrial Nucleic Acid Purification and Analysis

During the last years the structure and gene content of the mitochondrial genome of land plants have been subject of intensive molecular investigations. Because of the large size (200–2500 kb), and the complex, multipartite organization, the actual configuration of the mitochondrial genome and its coding capacity is still unclear (1 ). A currently accepted model suggests that the mitochondrial genome of higher plants is organized as multiple circular molecules. A master chromosome is assumed to represent the entire mitochondrial genome, although its existence in vivo has not been shown. However, subgenomic circles, which are formed by intra- and/or intergenomic homologous recombination via direct and/or inverted repeats, have been found in almost all land plants (2 ,3 ). In addition, circular or linear DNA plasmids of low molecular weight have been reported in plant mitochondria (4 ,5 ).