Rous sarcoma virus nucleotide sequences in cellular DNA: measurement by RNA-DNA hybridization.

Kinetic analysis of the hybridization of 71S RNA from Prague strain of Rous sarcoma virus with an excess of DNA from virus induced sarcomas indicated the presence of the majority of the viral genome sequences in cellular DNA with a very low average frequency per cell. About one-third of the viral sequences were at least partially complementary to DNA sequences with a higher average frequency on the order of 50 to 100 per cell. Normal chick embryo DNA was distinctly different, but contained sequences at least partially homologous to some fraction of the viral RNA.