Comparative investigation of DNA from mouse and Ehrlich ascites tumor cells

Mouse DNA and DNA of Ehrlich ascites tumor have been comparatively studied in the search for changes in DNA during tumor progression. No differences were found in kinetics of homologous (mouse X mouse) and heterologous (mouse X tumor) DNA reassociation; in thermal stability of homologous and heterologous duplexes of repeated, unique and satellite DNA; in percentage of hybridization with mouse liver heterogenous nuclear RNA; in thermal stability of the RNA.DNA hybrids. The negative results suggest that the considerable evolution of transplantable tumors (both in biological properties and in karyotype) has not been accompanied by alterations of the genome which could be detected by the now available methods of molecular hybridization for studying DNA divergence. In the light of the results obtained the functions ascribed to the mouse satellite DNA are discussed.