Foreign DNA Integration and Its Implications via Epigenetic Mechanisms: Oncology and Evolution

Abstract

The insertion of foreign DNA into mammalian genomes can alter their methylation and transcription patterns at sites remote from the locus of foreign DNA integration. The sites and extent of changes in the recipient cells might depend on the location of foreign DNA insertion. It is proposed that the insertion event itself, for example, of tumor viral DNA, via its epigenetic genome-wide consequences, plays an important role in (viral) oncogenesis. During evolution, the impact of ancient retrotransposon or retroviral genomes and the ensuing epigenetic alterations in the recipient genomes might have generated cells with completely different transcriptional profiles. Due to the continued presence of the transgenomes, these alterations are genetically stable and have been selected for or against by the environmental conditions prevalent at the time of foreign DNA insertion.