“What we’re finding is that after 10 years or so there are still markers, like fossils in our genome, telling us there was a trauma here. And that trauma may make this individual more susceptible to a second trauma or, even worse, a behavioral change, later in life.”
“We know that early life stress and the development of psychiatric disorders are related. We want to know how one leads to the other,” says Leslie Seltzer, a researcher at UW–Madison’s Waisman Center and a lead author on the study with neuroepigenetics researcher Ligia Papale. “We were surprised to see so many differences between our two groups, but now we can start looking at those differences more carefully, with the end goal of designing interventions, therapies, or medications that could resolve or even prevent those problems.”
Seltzer, Papale and collaborators collected saliva from 22 girls from 9 to 12 years old, and analyzed the samples to see which genes were actually at work managing biological processes. They were looking for a molecular modification called methylation. In methylation, environmental changes spur the attachment of a particular molecule, called a methyl group, to susceptible sites on genes.
“What you eat, your life experiences, how much you exercise, all of these things can modify your DNA methylation levels,” says UW–Madison neurosurgery professor Reid Alisch, who studies the regulation of gene expression in disease, especially mental illness. “DNA methylation doesn’t change your DNA, but the presence or absence of DNA methylation can change the way your DNA is used and whether or how much genes are expressed.”
The researchers found 122 genes where methylation of the high-stressed kids’ DNA differed from their low-stress peers. The team also looked at how genes were expressed. In all, more than 1,400 genes showed a difference in expression connected to the amount of stress the girls had experienced, including a dozen of the differently methylated genes.”
via Childhood stress leaves lasting mark on genes
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