epigenetics

noun

study of gene expression changes
the study of the mechanisms of temporal and spatial control of gene activity during the development of complex organisms
the study of mitotically and/or meiotically heritable changes in gene function that cannot be explained by changes in DNA sequence

Pronunciation: /ˌɛpɪd͡ʒəˈnɛtɪks/

Etymology: Blend of epigenesis + genetics; coined by C. H. Waddington in 1942.

The study of the processes involved in the genetic development of an organism, especially the activation and deactivation of genes.
“Epigenetics deals with the regulation of genetic activity within a cell - which genes are switched on or off, and when it happens.”
“The nuts and bolts of how this happens revolves around the massively trendy field of “epigenetics,” revealing how early life experience causes long-lasting changes in gene expression in particular brain regions.”
The study of heritable changes caused by the activation and deactivation of genes without any change in DNA sequence.