Evolution and humans: immigration epigenetic effects (Evolution)

by David Turell @, Friday, April 20, 2018, 18:39 (1806 days ago) @ David Turell

The children and grandchildren of immigrants may show psychological problems:


"Moving to a new country is a stressful experience, putting migrants at increased risk of anxiety disorders. But they aren’t the only ones who suffer: their children and grandchildren also experience more anxiety and higher rates of suicide than the general population.

"This might be down to the discrimination experienced by ethnic minorities, or to chemical markers of stress inherited through the generations.


"Pignon and his team compared the results of migrants with those from the native population. They also singled out responses from second and third-generation migrants: people whose parents and grandparents would be defined as migrants.

"After accounting for sex, age, income and education levels, Pignon’s team found that first, second and third-generation migrants were all more likely than the native population to experience anxiety disorders. Surprisingly, third-generation migrants have the highest rate of anxiety disorders, although it is unclear why. “The risk increased across the three migrant generations for social anxiety disorder and generalised anxiety disorder,” the team reports in its paper.

"Across the generations, migrants with anxiety disorders were also more likely to have psychotic disorders, bipolar disorder and addictive disorders, and had a higher rate of suicide attempts, compared with members of the native population with anxiety disorders.

"People who move from areas with poor living conditions – such as a lack of food, poor water quality or war – to healthier environments tend to improve pretty quickly, says Barry Bogin at Loughborough University, UK, who has studied Mayan migrants to the US. “The kids get taller, for example,” he says. “But then research suggests that status deteriorates in the second generation as people face bias, discrimination and maybe language difficulties.”

"Pignon and his team found, for example, that the migrants in their study tended to have a higher educational level, but a lower income, compared with the native population. “My grandparents came to the US from Eastern Europe after the war,” says Bogin. “I don’t speak those languages, but have I ever faced bias, even though I’m the third generation? Yes. It hasn’t affected my growth, but it probably has affected my psychology and attitudes.”


"The psychological impact of migration could be passed down through generations epigenetically, says Bogin. There is evidence that stress can trigger chemical changes that alter how genes make proteins, and that those changes can be passed to children and grandchildren.

"It is difficult to know whether the findings will apply to all migrants, says Jayaweera. “The health impact of migrant status can depend on the person’s background, and whether they come as an economic migrant, or to join family or seek asylum,” she says."

Comment: The results in grandchildren look to be multifactorial, based on this study. In our family on both sides the grandparents came for economic reasons and to escape discrimination. They carefully integrated fully into American society and culture, and spoke English without accent. There is no evidence in my cousins of any of these problems, and most have been very successful. However, epigenetics may well have played a role.

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