Epigenetic Inheritance

Epigenetic inheritance describes the transmission of gene expression patterns, meaning which genes are switched on or off, from one generation to the next through mechanisms other than changes to the underlying DNA sequence itself, most commonly through chemical modifications such as DNA methylation or through associated changes to the proteins DNA is packaged around. Conrad Waddington, a British developmental biologist, coined the term epigenetics itself in the early 1940s to describe how genes interact with their environment to produce an organism's observable traits, though the modern molecular understanding of specific heritable epigenetic marks developed substantially later, from the 1970s onward as DNA methylation and related mechanisms were characterized in detail. Because these chemical marks can, in some documented cases, be preserved through cell division and even passed from parent to offspring without altering the DNA sequence itself, epigenetic inheritance provides a mechanism by which an individual's environment or experience can potentially influence gene expression patterns in its descendants. The extent to which epigenetic inheritance operates in mammals, including humans, and across how many generations any such heritable effect can persist, remains an active and still substantially unsettled area of ongoing research.