TEMIN'S DNA provirus h ypothesis l, according to whi ch
the replication of t he RNA or RNA tumour viruses takes
place t lu'ough a DNA intermediate, explained t he following
unique features of infections with RNA oncogenic viruses :
(a) the heritably stable t ransformation of normal cells
induced with t hese v iruses; (b ) the appa.rent vert ical
transmission of high leukaemia frequency in r eciprocal
crosses betwecn high and low frequency strains of mice!! ;
and (c) t he r equirement for DNA synthesis3 in the early
stages of infection.