INTEGRATION OF FOREIGN DNA AND ITS CONSEQUENCES IN MAMMALIAN SYSTEMS

The insertion of foreign DNA into the genomes of established cells and organisms and the consequences of this integration event are of signi ficance for Viral oncology, reverse genetics, transgenic organisms, hu man somatic gene therapy and evolution. This review summarizes recent experimental findings and focuses on the alteration of cellular DNA me thylation at regions remote from the site of insertion, We also discus s experimental data demonstrating that foreign DNA ingested by mice is not completely degraded in their gastrointestinal tracts; fragments o f this DNA have been found to be covalently linked to DNA with 70% hom ology to the mouse IgE receptor gene.