Horizon Season 2005 Episode 20 The Ghost in Your Genes

The Horizon season 2005 episode 20, "The Ghost in Your Genes," explores the newly discovered science of epigenetics and how it challenges traditional understanding of genetics. This episode focuses on a ground-breaking study in Sweden, where the grandchildren of men who experienced a famine in their adolescence were found to have significantly lower rates of heart disease and diabetes. The study reveals that environmental factors, such as diet and stress, can actually alter the way genes behave and be passed down through generations.

Dr. Marcus Pembrey, a geneticist at the Institute of Child Health in London, takes us on a journey to understand the complex relationship between our genes and the environment. He explains that our genes do not work in isolation but are instead affected by outside influences. Dr. Pembrey shares information about an experiment he conducted involving pregnant rats who were fed a specific diet while pregnant. The offspring of these rats were then analyzed to show that they had different gene expressions compared to a control group.

We meet the Swedish study team, who are also exploring whether epigenetic changes may be a potential cause of the rise in mental disorders like autism. This theory is also supported by an experiment by Professor Moshe Szyf from McGill University who finds that mice who are frequently licked by their mothers exhibit less stress and anxiety because the maternal licking methylates certain genes that combat stress and anxiety. Consequently, these mice grew up into adult mice who were more resilient to stress.

Additionally, we discover how epigenetic changes may be linked to the aging process. Dr. Steve Horvath from UCLA uses epigenetics to measure biological age - a more accurate measure of aging than the traditional calendar age. He also talks about an experiment conducted on mice where epigenetic changes were found to reverse the aging process.

The episode also touches on the ethical implications of epigenetics like: to what extent should we be responsible for our children’s behavior when we know their genomic risks, especially when those risks are a result of epigenetic changes. They question whether we will need to redefine our concept of free will if we learn that our DNA is not solely responsible for our behavior.

Overall, "The Ghost in Your Genes," is a captivating episode that highlights a major breakthrough in understanding the complex relationship between environmental factors and genetics. It opens up a new area of research forcing us to re-think our understanding of genetics, and the implications that epigenetic changes has on human well-being.