Scientists have identified 1,260 genetic variants linked to human personality, revealing new connections between DNA, behaviour, health, careers and other aspects of everyday life.
The large-scale study, involving up to 1.14 million people across 46 research groups, provides one of the clearest pictures yet of how genetics may contribute to the way people think, feel and behave.
Researchers examined the five major personality traits known as the Big Five: extraversion, agreeableness, conscientiousness, neuroticism and openness to experience.
They identified 1,260 genetic variants associated with these traits, including 824 that had not previously been linked to personality. The findings were published in Nature.
But, the researchers stressed that there is no single gene that determines whether someone is outgoing, anxious, organised or adventurous.
Instead, personality appears to be influenced by thousands of genetic differences, with each individual variant making only a tiny contribution.
“When it comes to personality, there is no single gene,” the researchers said. While the combined effects of many genetic variants may be more meaningful, genetics still explains only part of the differences seen between people.
The study found that common genetic variants accounted for about 4.8 to 9.3 percent of the variation in measured personality traits, depending on the trait and analysis used. This means that most of the differences between people are not explained by these common genetic variants alone.
Environment, upbringing and life experiences continue to play important roles.
The researchers also discovered that genetic patterns associated with personality were connected to a surprisingly wide range of life outcomes.
These included physical and mental health, longevity, education, career choices, income and everyday behaviours.
The findings suggest that personality may influence many areas of life, while genetic factors that contribute to personality may also be linked to biological and behavioural pathways that affect those outcomes.
For example, genetic patterns associated with conscientiousness were linked to behaviours such as greater daytime activity. Variants associated with openness and extraversion were also connected with differences in sleep patterns and a greater tendency to remain active later in the day.
Researchers also found links between personality-related genetic patterns and employment outcomes, including income and job changes.
However, these associations do not mean that a person’s DNA determines their career, income or health.
Instead, the findings show statistical relationships across large populations. They cannot be used to predict exactly how a particular person’s life will unfold.
The study also provides evidence that genetics and environment are closely intertwined.
A person’s genetic tendencies may influence the environments they choose or encounter, while those environments can, in turn, reinforce or modify aspects of their personality.
Researchers say this interaction helps explain why personality cannot be understood through genetics alone.
The study found that genetic associations with personality were broadly consistent across different age groups, countries and methods of measuring personality. Family-based analyses also suggested that the findings were not simply the result of people growing up in the same household.
Despite the size of the study, scientists caution against interpreting the findings as a way to determine someone’s personality from their DNA.
The individual genetic effects were extremely small, and the researchers found that genetic variants explain only a modest share of personality differences.
The results, instead,
point to personality as a highly complex trait shaped by the combined effects of biology, environment and life experience.
Researchers say the findings could have implications far beyond psychology. Understanding how personality-related genetic factors are connected with health, education, work and behaviour could open new areas of research in medicine, public health and the social sciences.
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