In a provocative report from the frontiers of biology, NOVA explores new findings that call into question the long-held belief that all inherited traits are passed on by our genes. The fast-growing field of epigenetics investigates hidden influences that could not only affect our health today but that of our descendants far into the future. It now appears the environment we live in makes small chemical changes to our DNA without affecting the gene’s overall makeup:  In other words, epigenetics adds another layer to our DNA that acts as a control system of “switches.” Variable life experiences, such as nutrition or stress, may trigger these switches, turning genes on or off. According to the new research, these subtle changes can then be “remembered” and passed on from generation to generation, altering the traits we inherit. So the lives of your grandparents – the air they breathed, the food they ate, even the things they saw – could possibly affect you, and that what you do in your lifetime could, in turn, affect your grandchildren. NOVA delves into this fascinating new idea, interviewing top scientists in the field and following what could be a paradigm shift in the way we think about inheritance and our genes.

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