Largest Genetic Study Yet Finds Genes Play Only a Minor Role in Personality

Personality Traits: A Wide-Ranging Genetic Analysis

According to НВ — Техно: The most extensive genetic investigation of personality ever conducted has examined data from 1.14 million individuals drawn from 46 groups. Its aim was to analyze the five core dimensions known as the “Big Five”: extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience. A total of 1,260 genetic variants were found in connection with these dimensions, and 824 of them had not previously been associated with personality.

Differences in DNA account for roughly 7.4 to 10.6 percent of the differences seen among people on the Big Five traits. Yet when personality was predicted from genetic information alone, those data accounted for less than 4 percent of the variation. Looking at siblings and fraternal twins also showed that genetic effects within families were almost identical to those between unrelated people. That points to the same conclusion: most of what makes people differ in personality is linked to living conditions and other environmental factors.

For psychologists, this is a critical piece of evidence in the nature-versus-nurture debate, showing how much remains shaped by the world around us rather than by inheritance.

Genetic Variants Linked to Extraversion and COVID-19

The results also identified a notable connection between genetic variants tied to extraversion and the risk of catching COVID-19 during the initial phase of the pandemic. One likely explanation, according to the researchers, is that extroverts have a stronger urge to socialize and therefore were more likely to be exposed. Findings for agreeableness, however, were not consistent across all participant groups, possibly because of cultural differences, age patterns, or variations in how psychological questionnaires were designed.

As study author Michelle Nevard commented, “Our genes clearly influence personality-related tendencies.”

The findings were released on September 3 at 13:33 and reinforce the view that environmental influences deserve far more attention in personality science. Further research is needed to clarify the exact role of inherited factors. Combining genetic and environmental perspectives may also carry practical benefits for psychology, psychiatry, and social science-especially in creating better treatments for mental disorders and supporting general well-being. Personality, this work suggests, is not fixed by heredity but is deeply shaped by the conditions people live in.

While the recent study highlights the limited role of genetics in shaping personality, it also opens the door to exploring how other biological factors, such as gut and mouth bacteria, might influence psychological traits. For instance, a recent Portuguese study revealed interesting statistical correlations between psychopathic traits and microbial composition. This suggests that our environment, including the microbiome, could play a significant role in personality development.