Your Genes Are Affected by Stress

CHAPTER 15

  

Your Genes Are Affected by Stress

PART 1

What Stress Does to Genes

How can stress affect our genes, the permanent building blocks that make each of us unique? Chalk it up to epigenetics—the science studying factors that affect how and whether certain genes are expressed without altering our genetic makeup. ( See Keyword: Epigenetics for more on how this works.)

A 2010 study of 100 citizens of Detroit, Michigan, analyzed over 14,000 genes from blood samples. Of the 100 study subjects, 23 suffered from post-traumatic stress disorder. The researchers were looking for patterns of methyl groups, made of carbon and hydrogen, which can affix themselves to genes and switch them off. The 23 PTSD sufferers had six to seven times more genes without methyl groups attached than the other subjects had. Most of those genes were involved in the immune system. The PTSD sufferers also had higher levels of antibodies to herpes virus, further evidence of compromised immune system. READ MORE

Other interesting evidence of stress's effect on our genes' expression comes from animal studies. According to a 2010 study in Biological Psychiatry, a team of researchers in Switzerland raised male mice from birth. To introduce trauma, the mice were randomly separated them from their mothers for the first two weeks. They were then cared for by their mothers under normal circumstances.

When they reached adulthood, the trauma of those first 2 weeks was evident. The test animals were jumpy and preferred isolation—symptoms of post-traumatic stress disorder. The researchers analyzed five genes in these mice, including one that regulates the neurotransmitter serotonin, and found that all five were distinctly underactive, or overactive. Evidence mounts that while our life experiences don't change our genes, they can determine much about how our genes work. LESS
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PART 2

Genes Help Predict How You Handle Stress, Too

Our genes can help determine whether stressful experiences cause us to develop long-term effects. A gene known to help regulate serotonin was examined in college students at Northern Illinois University, the site of a mass shooting in 2008. Researchers compared the post-trauma psychological profiles of a group of students, and found that those with certain genetic differences in a serotonin transporter gene were more likely to have developed post-traumatic stress disorder (PTSD) after the shooting.

A study of 424 survivors of the Rwanda genocide of the 1990s found another genetic marker. All were refugees from the war and had experienced trauma during the genocide. Some had post-traumatic stress disorder, while others didn't. Researchers found that those who had a genetic predisposition to low levels of an enzyme that breaks down certain stress hormones were more likely than the other subjects to have developed PTSD.
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