Biological Obstacles to Success (04:01)
Researchers have found early life experiences leave chemical marks on our DNA that switch genes on or off. Development factors include diet, environmental toxins, housing, safety, and parent stress levels. Poor children are the most vulnerable to health issues.
DNA Methylation Study (02:36)
Mothers of genetically identical mice were fed different diets while pregnant. Those fed pellets rich in methyl groups gave birth to skinny, brown pups; those without gave birth to yellow, obese ones. Researchers identified the Agouti gene as responsible.
Learn about molecular switches affecting our fixed genes. Gene activity patterns can change cell form and function and turn on and off genes involved in appetite, fighting disease, and emotions. The Agouti gene affects metabolic rate and fat storage.
Bisphenol A Epigenetic Study (01:43)
Scientists are now thinking about DNA as a molecule. Pregnant mice fed BPA gave birth to mice with less methylation and more active Agouti genes. However, feeding them diets rich in methyl groups counteracted the effects of toxins.
The Social Environment (01:47)
A child's physical, social and economic environments can change their epigenome as toxins can—including their neighborhood, personal relationships, exposure to stressors, and feelings of safety or insecurity.
Social Toxins (05:29)
In the 1990s, neurobiologist Michael Meaney began studying how stress in early life could affect adulthood. In a rat study, maternal licking of pups predicted self-confidence and coping skills. Less licked rats had fewer glucocorticoid receptors to dampen the stress response.
Stress and Maternal Care (01:59)
Mother rats given inferior nesting material licked and groomed their babies less than those with soft material. The strain of providing shelter with few resources impeded their care efforts. Their offspring had difficulties turning off their stress response.
The Wisconsin Studies (02:49)
Many American families face increasing stressors, including less job security. In 1990, researchers began measuring stress levels in working middle class families to see how it affected child development. Children exposed to stress early in life had long term behavioral difficulties.
Second-Hand Stress and Epigenetic Effects (02:59)
Professor Marilyn Essex took saliva samples of working families to measure their stress hormone levels. Epigeneticist Michael Kobor analyzed these to correlate switch patterns in adolescents with maternal stress during infancy—producing similar results to a study in rats.
The Gradient (02:18)
The Wisconsin Studies raise the question of whether epigenetic changes occur on a sliding scale connecting wealth, power, and status to wellbeing. One quarter of U.S. children are born into poverty and are exposed to social stressors.
Negative epigenetic effects can be altered. Pregnant obese yellow mice fed an enriched diet gave birth to slender, brown pups. Meaney reversed the effects of nervous, low-licked rat pups by placing them in a "daycare" environment.
Biology and Public Policy (03:12)
Epigenetic changes with negative health impacts have been linked to adverse environments during early life. Scientists advocate investing in protective and supportive measures for children and families, such as universal preschool, to improve health outcomes for the next generation.
Credits: DNA Is not Destiny: How the Outside Gets under the Skin (02:33)
Credits: DNA Is not Destiny: How the Outside Gets under the Skin
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