Epigenetics

What is Epigenetics?

Epigenetics studies changes in gene regulation that occur without changing the underlying DNA sequence. Mechanisms such as DNA methylation and histone modification affect how genes are expressed. Environmental exposures and stress can influence these processes.

How it works

DNA is packaged with proteins called histones. Chemical modifications to DNA or histones can affect how accessible genes are to the machinery that reads them. DNA methylation and histone acetylation are two examples. Their effects can change gene activity without rewriting the genetic sequence.

What gets inherited?

Here is where the word “inheritance” can cause trouble. An epigenetic state persisting as a cell divides is one thing. A parent's acquired experiences being transmitted through eggs or sperm to later generations is another.

Transgenerational epigenetic inheritance has been demonstrated in some organisms. In humans, shared environments, genetic inheritance and direct prenatal exposure can produce patterns that look like it. Heard and Martienssen's review (2014) explains why evidence of an environmental effect on gene regulation is not, by itself, evidence that an acquired trait passes to future generations.

Epigenetics and the brain

Epigenetic regulation is involved in nervous-system development, neural plasticity, learning and memory. Researchers also study it in neurological and psychiatric disorders. It offers a way to investigate how gene activity relates to experience and behavior, without assuming that every experience leaves an inherited molecular record.