From ancient nomads to modern job-hoppers, the urge to move may be written partly into our DNA.
People’s tendency to set down roots far from where they were born is partly inherited and grounded in early brain development, researchers report February 6 at bioRxiv.org. What’s more, the underlying genetic signatures appear both in modern populations and in ancient human genomes dating back thousands of years.
The findings, based on a large genetics study, suggest that long-distance migration is shaped not only by jobs, housing and politics but also by biological traits linked to cognition and risk-taking that have been favored by evolution for millennia.
“There is something in our genome that affects our decisions” to move, says Ivan Kuznetsov, a behavioral geneticist at the University of Tartu in Estonia who was not involved in the research.
For the new study, neurogeneticist Jacob Michaelson of the University of Iowa in Iowa City and colleagues analyzed genetic data from about 250,000 people in the United Kingdom and compared how far people lived from their birthplace with DNA patterns across their genomes. They found that people who moved farther tended to share variants in genes involved in brain development, particularly those active in cells known as excitatory neurons, which play key roles in learning, planning and weighing uncertain outcomes.
Although these genetic differences accounted for only a small slice of migration behavior — around 5 percent of the differences in how far people move — the signal held up even after accounting for education and health, suggesting that the itch to move isn’t just about diplomas or well-being, but is rooted, at least in part, in our biology.
The genetic patterns were not unique to modern societies either. Michaelson’s team analyzed ancient DNA sequences from more than 1,300 individuals who lived as long ago as 10,000 years. The same migration-linked genetic variants predicted how far people moved during their lifetimes in the past, as measured by the distance between individuals’ inferred birthplaces and burial sites.
Such variants also rose in frequency over time, a sign that natural selection has favored traits linked to mobility and exploration as humans spread into new environments. Even centuries after the Age of Exploration, when global empire-building reshaped flows of human movement during the 15th and 16th centuries, those ancient tendencies still seem to influence who moves today — and which places stand to benefit economically.
A separate analysis of U.S. data hinted that these genetic tendencies may shape regional economic fortunes. The researchers calculated an average “migration score” — a DNA-based estimate of how inclined people are to move far from home — for people in 222 counties, drawing on genetic data from more than 3,000 adults recruited through an autism research study. They found that counties that gained more residents with migration-linked genes tended to experience faster income growth later.
That trend raises the possibility that long-distance movers may contribute to economic dynamism at the local level, perhaps by bringing new skills, ideas or risk-taking energy to the communities they join. Still, scientists caution that the analysis is exploratory and cannot show cause and effect.
“This is pretty logical,” says Vasili Pankratov, an evolutionary geneticist at the University of Tartu who, together with Kuznetsov, coauthored a study last year linking genes to contemporary migration patterns in their country. But, Pankratov says, “Whenever you enter the social behavior genetics space, things become very complicated.”
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