Specific features of the structural organization of the mitochondrial genome in rat liver

The nature of intramolecular heterogeneity of mtDNA in the liver of white rats has been studied. The peculiarities of the melting curve, and the possibility of DNA fractionation of nucleotide compounds with hydroxylapatite (HA) column chromatography has shown the presence of sequences differing in the mean nucleotide content. A section of about 350 pairs in size repeated four times was found in the reassociation of most thermolabile fraction with a mean composition of 28% GC. These sections are well seen on the denaturation map of the recorded molecules formed in the range of temperature transition 'helix-coil'. The distance between the centers of fusible sections (in percentage of total length) is 32.5, 32, 14.0 and 21.5.