The work was undertaken to estimate quantitatively the functional activity of tumor cell genome and possible variations in the relationship between nuclear genome and mitochondrial genetic determinants in tumor cell. For this purpose in mice C3HA tumors of hepatocellular origin were induced with N-nitroso-N-diethylamine, tissues of one of which were subjected to successive isologous transplantation during the period over 3 years. Normal hepatic tissues were taken for the control. As a result of a series of independent experiments (actinomycin D spectrophotometric titration, acridine orange binding, template activity, nuclear RNA/DNA hybridization) the results were obtained indicating a decrease in the amount of active loci in tumor hepatocytes genome. Hybridization data also indicate that in the tumor the derepression of chromosomal genes responsible for the genetic control over mitochondria and a non-regulated de-repression of mitochondrial genetic determinants take place.

A review of literature and the authors own data on specific and non-specific effect of DNA on the organism and eucaryote cells are presented. A conclusion is made that transduction and transformation in eucaryotes might be possible. It is confirmed by a great number of experimental data. The problem on mutagenic effect of DNA still remains disputable. The problem of DNA restriction in eucaryotes is absolutely unstudied and requires experimental development. A great theoretical and practical significance of the studies in the effect of exogenic DNA in higher organisms is emphasized.