The largest genetic study of human personality to date has linked more than 1,200 spots in the genome to differences in how outgoing, anxious, organized or open to new experience people tend to be — while underscoring that no single "personality gene" exists and that DNA still leaves most of the variation unexplained.
The study, published in Nature on September 2, was carried out by the Revived Genomics of Personality Consortium and drew on data from roughly 600,000 to more than a million participants, depending on the trait, pooled across 46 cohorts in more than a dozen countries. Researchers scanned each person's genome against their scores on the "Big Five" personality dimensions — openness, conscientiousness, extraversion, agreeableness and neuroticism — and identified 1,260 genetic variants associated with at least one trait, 824 of which had never before been linked to personality.
Small effects, added up
Even combined, the variants captured in the analysis accounted for only a modest slice of personality differences between people — estimates across traits ranged from roughly 7 to 13 percent, according to researcher summaries of the findings. That leaves the large majority of variation tied to environment, upbringing, and factors the genetic data can't capture. Lead researcher Ted Schwaba of Michigan State University, who worked on the analysis, put the scale of any single variant's influence in perspective.
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, Michigan State University
The team also checked whether the genetic signals held up across different populations and survey methods — comparing, for instance, whether variants linked to extraversion in Dutch young adults predicted the same trait in older American adults — and found the associations were largely consistent. Several of the identified variants overlapped with genes already tied to health and behavioral outcomes: variants linked to neuroticism were associated with higher rates of hospitalization, while those tied to conscientiousness tracked with lower body mass index and reduced likelihood of taking up smoking.
Outside researchers who reviewed the work, including University of Texas at Austin's Elliot Tucker-Drob and University of Bristol's Michel Nivard, both involved in the consortium, stressed that the results should not be read as genetic determinism. Personality, they noted, develops through the ongoing interplay of genes, family and social environment — and the authors explicitly warned against using the variants for employment screening, insurance underwriting or other individual-level predictions, given how small and probabilistic each genetic effect is.
The consortium says it plans to expand the dataset to include more genetically and culturally diverse populations, since most participants so far have been of European ancestry — a limitation that could affect how well the findings generalize worldwide.
