What does epigenetics mean?
Epigenetics is the branch of biology concerned with changes in gene expression that occur without any alteration to the underlying DNA sequence. Rather than modifying the genetic code itself, epigenetic mechanisms — such as DNA methylation and histone modification — act as a system of switches that determine whether particular genes are active or silent. These modifications can be influenced by factors including diet, stress, toxins, and age, and many of them are stable enough to be inherited when cells divide, with some evidence suggesting effects can pass across generations. The word is formal and technical, appearing chiefly in scientific literature, medicine, and popular-science writing, though its reach has widened as research links epigenetic change to cancer, aging, mental health, and development. Epigenetics matters because it reframes inheritance: two people (or twin cells) with identical genomes can behave very differently depending on which of their genes are switched on. It offers a powerful explanation for how nature and nurture interact at the molecular level.
nounThe branch of biology that studies heritable changes in gene expression that occur without alterations to the underlying DNA sequence. These changes, such as DNA methylation and histone modification, can be influenced by environment and experience and may be passed to daughter cells or across generations.
- The study of stable, heritable changes in gene expression that do not involve changes to the underlying DNA nucleotide sequence.
"Research in epigenetics has shown that diet and stress can alter how genes are expressed without changing the genes themselves."
"Epigenetics explains why identical twins, who share exactly the same DNA, can differ in health outcomes as they age."
"Her lecture introduced students to the growing field of behavioral epigenetics."
Your DNA is like a piano — epigenetics is what decides which keys actually get played.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does epigenetics come from?
The term combines the Greek prefix epi- meaning 'over' or 'upon' with 'genetics,' from Greek genesis meaning 'origin' or 'creation.' It was coined in the mid-twentieth century by British developmental biologist Conrad Hal Waddington, building on his earlier concept of the 'epigenotype,' to describe the processes linking genotype and phenotype during development. The modern sense — heritable changes in gene expression independent of DNA sequence — emerged from the 1990s onward as molecular mechanisms such as methylation were characterized.
Related word forms
How epigenetics is actually used
A formal scientific term used primarily in academic, medical, and popular-science contexts. It is almost always treated as an uncountable noun taking singular verb agreement ('epigenetics is...'). It is sometimes loosely used in wellness media to mean any environmental effect on health; careful writers reserve it for its precise biological meaning.
Easily confused with epigenetics
Eugenics is the discredited practice of attempting to 'improve' a population's genetic quality through selective breeding, whereas epigenetics is a legitimate science studying changes in gene expression not caused by DNA sequence changes.
Genetics studies genes and their transmission through DNA sequences, while epigenetics studies changes in gene activity that occur without altering those sequences.