Epigenetics and inheritance

Unexpected though it might be, there is now little doubt that epigenetic inheritance takes place. Experiments on rats have shown that female offspring who received good care when young, respond better to stress in later life and themselves nurture their offspring better. Female offspring receiving low-quality care, nurture their offspring less well. Good maternal behaviour in rats transmits epigenetic information onto their offspring's DNA without passing through an egg or sperm. In humans, when a mother has a condition known as gestational diabetes, the fetus is exposed to high concentrations of glucose. These high glucose concentrations cause epigenetic changes in the daughter's DNA, increasing the likelihood that she will develop gestational diabetes herselt. It is thought that in sperm and eggs during the earliest stages of development a specialised cellular mechanism searches the genome and erases its epigenetic tags in order to return the cells to a genetic 'clean slate'. However, a few epigenetic tags escape this process and pass unchanged from parent to offspring.