Genetics versus Epigenetics

Gene expression can be regulated at multiple levels, i.e. DNA structure, gene transcription, and/or posttranscriptional modifications. Four genetic mechanisms (DNA point mutation, deletion, rearrangement, and amplification) and two epigenetic mechanisms (DNA methylation and the preservation of DNA-protein complexes) can account for the majority of enduring changes observed in cultured cells.


Genetic alterations in DNA sequence appear to be largely responsible for altered growth regulation associated with transformation, but there is also evidence to suggest that epigenetic mechanisms play a role in transformation. Differentiation of cultured cells is often associated with lack of growth, and has been ascribed in part to epigenetic mechanisms. However, differentiation and transformation are not mutually exclusive but may be regulated by parallel multistep pathways.

EPIGENETICS refers to heritable changes in phenotype or gene expression caused by mechanisms other than changes in the underlying DNA sequence.