The emerging field of epigenetics shows how traumatic experiences can be transmitted from one generation to the next.
A key study in this emerging field, published in 2004, showed that the quality of a rat mother's care significantly affects how its offspring behave in adulthood. Michael Meaney of McGill University and his colleagues found that rat pups that had been repeatedly groomed and licked by their mothers during the first week of life were subsequently better at coping with stressful and fearful situations than pups who received little or no contact.
In the animal study led by Meaney, the epigenetic modifications and the changes in glucocorticoid receptor expression associated with them were observed in the hippocampus, a brain region that is essential for learning and memory formation. It is, therefore, possible that epigenetic markers are laid down during the formation of traumatic memories.