Science and Technology
05.09.2011

Stress parent leaves a lasting impression in the genes of children

Researchers focus on methylation, a central component of genes as opposed to the sequence of DNA base

Researchers at the University of British Columbia and Child & Family Research Institute, Canada, showed that parental stress during the few years of the children may leave a mark on the genes that lasts until adolescence and can affect how these genes are expressed more afternoon.

The study, published online in the journal Child Development, focused on epigenetics - gene expression as opposed to DNA base sequence. A central component is the epigenetic methylation, a chemical group that assigns parts of the DNA - a process that acts like a dimmer on the function of the gene in response to social and physical environment.

Associate professor, Michael S. Kobor, medical genetics at UBC, measured in DNA methylation patterns of cells collected from more than 100 teenagers, a process recently conducted by researchers at the University of Wisconsin. These patterns were compared with data obtained from the University of Wisconsin in 1990 and 1991, when these same children were teenagers and their parents were invited to report on their stress levels - including depression, family expresses anger, stress and stress on parents financial issues.

Comparing the DNA methylation to stress, Kobor's team found that higher levels of stress reported by mothers during the first years of the children correlated with levels of methylation in 139 parts of the DNA in adolescents. They also found 31 shares that correlate with the stress of parents reported more during the pre-school children (3.4 to 4.5 years).

"To our knowledge, this is the first demonstration, using carefully selected longitudinal data, which shows that adversity parents during the first year of a child leads to noticeable changes in the 'epigenome. It literally illustrates a mechanism by which internalized experiences can stay with us for a long time, "says scientist Kobor, Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute (CFRI), and Mowafaghian Scholar in Human Early Learning Partnership (HELP).

The team also found that the stress level of the father is more strongly associated with DNA methylation in daughters, while the mother's stress level has an effect in boys as in girls. This reinforces other research showing that father absence or lack of participation in parenting is associated with an earlier onset of puberty and difficult temperamental traits in girls but not boys.

In general, none of the genes, whose level of methylation correlated with stress are among the best known, have a role in controlling the behavior of a person or reaction to environmental stress. But they did find some genes that had a consistent change in methylation levels in more than one site of DNA, including one involved in the production of insulin and three other genes possibly involved in brain development. "What is particularly intriguing is that the higher levels of stress are a parent during childhood, but not during the preschool years, which leads to epigenetic changes. And the opposite is true for parents: increased stress during the preschool age of a child, but not during childhood, "says co-author estudom Clyde Hertzman, professor at UBC's School of Population and Public Health and director of HELP.

The co-author Thomas Boyce, a professor at UBC's Human Early Learning Partnership and CFRI scientist, says that these results confirm what early childhood experts know that the early years are a crucial period that prepares the ground for much of what happens with the individual later. And it helps explain why the socioeconomic status of a child is the most powerful predictor of child health and health throughout the life of that individual.

Source: Isaude.net