Epigenetics
Definition
Epigenetics refers to heritable changes in gene expression that do not involve alterations to the underlying DNA sequence. Epigenetic modifications—such as DNA methylation and histone modifications—regulate which genes are turned on or off without changing the genetic code itself.
Correct Scientific Usage
Researchers study epigenetic mechanisms that control gene expression in response to developmental stages, environmental exposures, and cellular conditions. Some epigenetic changes are reversible and respond to environmental factors including diet, stress, and toxins. Others are stable and can be transmitted across cell divisions or, in some cases, across generations.
Common Misunderstandings
Epigenetics is often portrayed as showing genes don't matter or that lifestyle completely controls genetic expression, when epigenetics actually describes one mechanism through which genes and environment interact. Epigenetic changes don't rewrite DNA—they modify how existing genes are expressed.
Why It Matters
Understanding epigenetics provides a mechanism for gene-environment interactions without genetic determinism or blank-slate environmentalism. It explains how identical twins with the same DNA can develop different diseases, how early-life experiences may have lasting biological effects, and why genetic risk can be modified by environmental factors.
References
- Epigenetics, National Institute of Environmental Health Sciences
- Epigenetic Inheritance: Concepts, Mechanisms and Perspectives, Frontiers in Molecular Neuroscience