We’re pretty used to thinking ‘it’s all in the genes’… that we are who we are because of the genes we received from our parents. But what if we are who we are not only because of the genes our parents gave us, but also because of the environment in which our grandparents lived?

Turns out, it’s not ALL in the genes—external and environmental factors can influence the way an organism’s genes are regulated. This is just part of a field of genetics known as epigenetics—‘epi’ coming from the Greek for ‘over, on top of’. Epigenetics is an additional layer of instructions that lies ‘on top of’ DNA, controlling how the genes are read and expressed.

Epigenetics can be thought of as the interpretation of the genetic code. Just as the same piece of music will change slightly when interpreted by different orchestras, so does our genetic ‘score’ when interpreted by the epigenetic orchestra.

http://www.nova.org.au/people-medicine/epigenetics