Study identifes genetic variants that shape human personality traits

An international consortium of researchers found that more than 1,200 different genetic variants are associated with the Big Five personality traits - and surprisingly, these personality genetics are linked to dozens of life outcomes.

This study, led by the Revived Genomics of Personality Consortium, combined results from 46 different research cohorts around the world. Participants in each cohort provided a DNA sample and completed a questionnaire that measured the Big Five personality traits: openness to experience, conscientiousness, extraversion, agreeableness and neuroticism. These Big Five personality traits are relatively stable and habitual differences in how people think, feel and act. These DNA samples were then linked to differences in people's personality traits.

There is no single 'personality gene. Personality traits are associated with many genetic variants, but even the largest effects of individual genetic variants are still very small. However, even though any individual genetic variant makes very little difference in personality, the effects of many variants together can be more sizeable."

Ted Schwaba, lead author of the study and faculty at MSU's Department of Psychology

Combined together, the researchers found that the genetic effects were more sizable and robust. For example, the same variants linked to extraversion in a young adult in the Netherlands also predicted extraversion in an older adult retiree in the United States. Using methods that compared relatives to one another, the team also confirmed that these genetic links weren't actually the byproduct of a shared upbringing. Despite these genetic associations, they found that the environment still plays a major role in personality.

The researchers note how relevant the genetics of personality are to so many parts of the human experience. The genetic variants that predict personality also partially predict mental and physical health, longevity, education, career paths and outcomes and even how people are perceived by close others. Genetic variants linked to conscientiousness, for example, were associated with being more active during the day while variants linked to openness to experience and extraversion were linked to being more of a night owl.

Researchers say the findings point to an interconnected relationship between genetics and the environment. For example, the study found that common genetic variants linked to openness to experience predicted that a person would move to more cosmopolitan neighborhoods. In turn, living in those neighborhoods may reinforce and further shape that same trait.

"Personality seems to be relevant nearly everywhere you look. We hope this study will encourage many other scientists to incorporate personality traits into their fields of study," said Schwaba. "For example, genetic variants associated with neuroticism predict more time spent in the hospital, which is relevant to physicians and health researchers, and variants associated with openness to experience are linked to income and switching jobs, which is relevant to vocational researchers."

Funding was supported in part by grants from the National Institute of Mental Health and the National Institute on Aging.