The team also found that fathers' stress level is more strongly associated with DNA methylation in daughters, while mothers' stress level has an effect with both boys and girls. This reinforces other research showing that the absence of fathers or their lack of participation in parenting is associated with an earlier onset of puberty and difficult temperamental traits in girls, but not in boys.
In general, none of the genes whose methylation level correlated with stress were among those best known to play a role in controlling a person's behaviour or reaction to environmental stress. But they did find some genes that had a consistent change in methylation levels at more than one site on the DNA, including one involved in the production of insulin, the hormone that regulates blood sugar levels, and three other genes possibly involved in brain development.
"What is particularly intriguing is that a mother's higher stress levels during infancy, but not during the preschool years, leads to epigenetic changes," says co-author Clyde Hertzman, a professor in UBC's School of Population and Public Health and director of HELP. "And the opposite is true for fathers it's their higher stress during a child's preschool years, but not during their infancy, that counts."
"These results confirm what early childhood experts have long known those first few years are a crucial period that sets the stage for much of what happens to the individual later in life," said co-author Thomas Boyce, a professor at UBC's Human Early Learning Partnership and a scientist at CFRI. "It helps explain why a child's socioeconomic status is the single most powerful predictor of childhood health and that individual's lifelong health."
|Contact: Brian Kladko|
University of British Columbia