Gene Regulation

Epigenetic Inheritance

Epigenetic inheritance is a heritable process that includes the passage of genetic information from parent to daughter cell, without alteration to the genome itself.
Epigenetic inheritance is the transmission of information from parent cell to daughter cell without mutations in the genome. Unlike general gene regulation, which takes place via DNA modification, epigenetic inheritance controls gene activity through phenotype, rather than genotype, modifications. This affects how cells read and respond to their genes. Epigenetic inheritance allows short-term changes in the body to have a permanent effect on cells. There is evidence that epigenetic inheritance can even be passed from one organism to its offspring, thus resulting in traits for which genes may not be at all responsible or for which genetic inheritance is an incomplete explanation. This phenomenon, known as transgenerational epigenetic inheritance, has been observed in both prokaryotes, organisms without a nucleus or membrane-bound organelles, and eukaryotes, organisms with a nucleus and membrane organelles, including humans. Transgenerational epigenetic inheritance may have significant implications for disease and longevity in humans. For example, a study of an isolated community in Sweden investigated the transgenerational epigenetic effects of both famine and beginning smoking early. Many of the effects were associated with sex. One of these effects was the sex-linked associations of fathers who began smoking early. Their sons, but not their daughters, had a higher body mass index (BMI). Similarly, the granddaughters, but not the grandsons, of paternal grandmothers who suffered a dramatic change in food availability in early life (up to 13 years of age) had higher risk of cardiovascular disease and early death. Studies have shown that smoking causes abnormal increases in hormones that stimulate hunger. Research has shown that grandmothers who smoke alter their own epigenome, passing on the tendency for increased hunger hormones to their daughters, leading to obesity in their daughters and even granddaughters. Evidence also shows that male-related inheritance is believed to be Y-linked chromosomal inheritance; what is observed between mother and daughter is X-linked chromosomal inheritance.
The premise of epigenetic inheritance is that the exposure of one generation to environmental or external agents, such as cigarette smoking, stress, or poor diet, has the potential to affect future generations to come.