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Epigenetic Mechanisms and their Toxicological Significance

Genetic Toxicology, Oncogenesis, Developmental and Reproductive Toxicology

  1. Rebecca E. Watson PhD, DABT

Published Online: 15 DEC 2009

DOI: 10.1002/9780470744307.gat082

General, Applied and Systems Toxicology

General, Applied and Systems Toxicology

How to Cite

Watson, R. E. 2009. Epigenetic Mechanisms and their Toxicological Significance. General, Applied and Systems Toxicology. .

Author Information

  1. IIT Research Institute, Toxicology Division, Life Sciences Group, Chicago, Illinois, USA

Publication History

  1. Published Online: 15 DEC 2009


Epigenetic mechanisms are processes that exert control over gene expression without altering the DNA sequence. These mechanisms essentially work as genetic switches, turning gene expression levels on and off in response to various stimuli. Currently, DNA methylation and histone modifications (particularly histone acetylation and methylation) are the best characterized and most commonly recognized epigenetic mechanisms, although in recent years attention has turned to additional epigenetic processes such as microRNAs. Together, these mechanisms form the epigenome, a dynamic, reversible construct necessary for differentiation, tissue-specific functions, development and neurological function in eutherian mammals. However, aberrant epigenetic function may lead to untoward effects and can be a contributing factor to a variety of diseases including cancer and developmental/neurological disorders. This chapter summarizes major epigenetic mechanisms and their relevance to toxicologists, including their role in normal biological functions vs. disease-associated processes, as well as how nutrition and xenobiotic stimuli influence the epigenome. An enhanced understanding of factors that affect the epigenome can assist in both predicting undesirable toxic outcomes and in designing therapeutic strategies.


  • epigenetics and toxicology;
  • DNA methylation;
  • histone modifications