Epigenetics
- [University of Washington]
- Overview
Epigenetics is the study of how environmental factors can change the chemicals attached to genes, which in turn affects how genes are expressed. These chemical marks, called the epigenome, accumulate on DNA during development and determine how much or little of a gene is expressed.
Some examples of environmental factors that can affect these chemicals include: Diet, Physical activity level, and Access to resources.
Three epigenetic mechanisms have been identified that regulate gene expression and silencing:
- DNA methylation: A chemical called a methyl group is added to DNA, which usually turns genes off. The methyl group can also be removed through a process called demethylation, which usually turns genes on.
- Histone modification: Methyl groups are transferred to histone proteins, which can stimulate neural pathways that are important for learning and long-term memory formation.
- Non-coding RNA (ncRNA)-associated gene silencing: Another epigenetic mechanism.
While epigenetic changes are necessary for normal development and health, they can also be responsible for some diseases, including Fragile X syndrome, Angelman's syndrome, Prader-Willi syndrome, and various cancers. Disruptions to the systems that contribute to epigenetic alterations can cause abnormal gene activation or silencing, which has been linked to cancer, syndromes involving chromosomal instabilities, and mental retardation.
[More to come ...]
