Host substitution in SV40 and polyoma DNA

The insertion of host DNA into the viral genome presumably involves a recombination like event between the viral and cellular genomes. Evidence for the integration of virus DNA into cellular DNA during SV40 and polyoma lytic infection has been reported. It is likely, therefore, that the substituted viral genome arises initially from the integration of virus DNA into the chromosomal DNA of lytically infected cells, followed by the excision of linked viral and cellular sequences. Consequently the authors studied the nature and variety of the host DNA sequences in different populations of substituted SV40 and polyoma viruses, and have attempted to relate the data to the number and nature of the viral recombination sites on the permissive host's genome.