Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=225220
Story Retrieval Date: 2/28/2015 1:17:12 PM CST
Marital satisfaction has a complicated puzzle of factors, but Claudia Haase has found one piece in human DNA.
“We are definitely more than our DNA,” Haase said. “But there is huge variation in how people react to marital satisfaction.”
In a study published in an online journal Emotion in October, Haase and other researchers at the University of California-Berkeley explore the effects of the 5-HTTLPR gene on marital satisfaction. They found that some forms of the gene predict heightened emotional responses to circumstances, whether they are good or bad.
Therefore, spouses with this genotype would be happier in marriage during the good times, but worse off during the bad.
The 5-HTTLPR gene, like all other genes, can vary depending on the way alleles, or gene variants, are expressed. Each of the two alleles in the 5-HTTLPR gene can be long or short. If a person has two short alleles, Haase and other researchers noticed, they have a greater emotional response to good or bad situations.
The study focused on long-term marriages because the scientists wanted to observe how the gene might affect emotional responses to stimuli over long periods of time. The couples that participated in the study were middle-aged or older and were married for at least 15 years.
Through DNA tests, conflict scenarios in a lab and satisfaction surveys, the researchers explored the possibility of whether couples with the same variation of the 5-HTTLPR gene had greater marital satisfaction.
“The gene story is a cooperative story,” Dr. Robert Levenson, the senior author of the study, said. “Our genes create slight biases to respond in particular ways. The impact of those biases is really different depending on the environment that we live in. That’s the message of this study.”
It is not that the gene indicates happiness level, Levenson said. But, the people with shorter alleles have bigger responses to emotional situations.
The study does not suggest that one combination of alleles is better than any other. Levenson noted that some might think the shorter alleles would be better because they would be unhappier in an unhealthy relationship and would therefore get out of it. On the other hand, those with longer alleles may be more likely to stick it out through a bad marriage because they are not as emotionally affected by bad times, he said.
In the end, Levenson said, it comes down to a combination of factors.
“It’s about the complex interactions between these biases to respond in particular ways,” Levenson said. “Whether something is good or bad is really dependent on social and personal values.”
The 5-HTTPL gene has long been studied as an important factor in emotional behavior for both children and adults, according to Jay Belsky of the University of California-Davis.
“This evidence shows that individuals actually vary in their susceptibility to being influenced by their experiences,” Belsky said. People with two short alleles are more sensitive to their environment, “for better or for worse.”
Belsky has termed the 5-HTTPL the “plasticity gene” based on its effects on the emotional state of people. Belsky said the study shows that this gene may help scientists understand how emotions in marriage operate.
One of the other findings of the study is that the allele combination seems to have a greater impact on behavioral response later in life. Other studies support this finding and perhaps later in life our nature trumps nurture, Haase said.
Haase, who became an assistant professor at Northwestern University in September, is engaged. She said talking about her research with her fiance has been fun for them as a couple, but she will probably not find out if they have common allele patterns.
“I don’t know my own and I don’t know his,” Haase said of her and her fiance’s genetic code. “I am curious to see, but there are some things I don’t have to know.”