Is Your Personality Written in Your DNA? A Study of Over One Million People Offers New Answers

How much of your personality was settled before you were born?

Are you outgoing because you grew up in a sociable family, or because your genes made you more inclined to seek out other people? And what about your self-discipline, your curiosity and the worries that keep you awake at night?

To find out, a large international team of researchers combined DNA and personality tests from up to 1.14 million people. The results were published in Nature in September 2026, and it is one of the largest genetic studies of personality ever carried out.

The researchers found 1,260 genetic variants linked to the Big Five personality traits. But perhaps the most interesting finding is how little each variant tells us about who we are.

Scientists searched more than a million genomes for personality

The study was led by Ted Schwaba and Elliot Tucker-Drob at the University of Texas at Austin, in a collaboration called the Revived Genomics of Personality Consortium. It brings together 46 research projects from the USA, the UK, Australia, the Nordic countries and the rest of Europe, among others.

Every participant had completed a personality test measuring the Big Five: extraversion, agreeableness, conscientiousness, neuroticism and openness to experience. And every participant had given a DNA sample.

The method is called a genome-wide association study. Researchers check around ten million places in the genome where people often differ, and look for variants that are more common among people who score high on a trait.

With so many participants, it suddenly became possible to see far more than before:

Trait	Variants found before	Variants found now
Conscientiousness	3	131
Agreeableness	4	39
Openness	8	126
Extraversion	14	258
Neuroticism	224	706

Neuroticism stands out because it was measured in the most people, over 1.1 million. The other traits were measured in 600,000 to 660,000.

Surprise 1: There is no "extraversion gene"

Here is the number worth remembering.

The researchers calculated how much a typical variant matters for extraversion. The answer was about 0.009 standard deviations. That is like moving from the 50th percentile to the 50.35th.

Imagine a thousand people standing in a queue, sorted by how outgoing they are. One such variant moves you past three or four of them.

And that was one of the variants strong enough to be detected. By the researchers' estimate, each of the five traits is influenced by around 16,000 independent variants on average. Personality is not controlled by a few genes. It is the sum of thousands of tiny nudges in different directions.

Try it yourself. With one variant, almost nothing happens. Only when thousands are added together do the genes start to tell people apart, and even then most people end up near the middle.

The study also challenges a popular idea. Extraversion and openness have long been linked to the brain chemical dopamine, and neuroticism, conscientiousness and agreeableness to serotonin. The researchers found little to support this. The genes point to the brain broadly, especially the frontal lobes and neurons in general, rather than to one particular brain chemical.

Surprise 2: Why does DNA show less heritability than twins?

If you have read about personality and genes before, you have probably heard that personality is about 40 to 60 percent heritable. A large review of twin studies landed at around 40 percent.

The new study arrives at a very different number: common genetic variants explain only 4.8 percent (agreeableness) to 9.3 percent (extraversion) of the differences in personality.

Does that mean the twin researchers were wrong? No. The numbers measure different things.

• Twin studies capture all genetic influence. Identical twins share their entire genome, including rare variants and combinations of genes that work together.
• DNA studies see only the common variants, and only the part of their effect that simply adds up. Rare variants and interactions are missed.
• Personality tests are not perfect. If you answer slightly differently on a day when you are tired, that is noise. Noise cannot be related to your genes, so it pulls the heritability estimate down.

The researchers tested that last point. The more reliable the personality test, the more heritable personality appeared. With a test of typical quality, the figure rose to 9.3–13.3 percent. Corrected for all measurement error, it reached 10.8–15.8 percent.

The authors also stress something that often gets lost in the headlines: whatever the method, personality is shaped to a large degree by the environment.

Surprise 3: Family does not explain the genes away

This may be the most important finding for scientists, even if it sounds technical.

When researchers find a link between genes and a trait, it can be a shortcut. Parents with genes for higher education often give their children more books and better schools. The genes then look stronger than they are, because they also capture the home the child grew up in.

For education, this is a well-known problem. When researchers compare siblings within the same family, the predictive power of education genes drops to around 60 percent of what it is in the wider population.

For personality, almost nothing happened. The researchers compared fraternal twins from the Netherlands and the UK, who grow up in the same home but inherit different genes. The twin with the higher genetic tendency toward extraversion was, on average, also the more outgoing one. Across all five traits, the genes predicted about as well within families as in the population at large: 96 percent.

An Icelandic analysis of parents and children gave the same answer. Personality genes work almost entirely through what the child actually inherits, not through what the parents are like.

Surprise 4: We do not choose partners for their personality

Many people believe that birds of a feather flock together, and that we pick partners who resemble us. For education, that holds up well. Genetically, parents resemble each other clearly in education.

For personality, the resemblance almost vanished. The genetic correlation between parents was 0.01–0.04, compared with 0.37 for education. Measured with ordinary personality tests, couples resembled each other a little more, but still not much. The exception was openness, where couples were most alike.

In other words, we seem to find partners with similar education and similarly curious minds, but almost at random when it comes to how talkative, tidy or anxious we are.

The genes show up in everyday life

The study also found many links between personality genes and how people live. The effects are small, but some are surprisingly concrete:

• Night owls and early birds. Among participants who wore activity trackers, the genes for openness were linked to more activity at night, and the genes for conscientiousness to more activity during the day.
• Where you live later in life. People with genes for high openness more often moved to urban areas with many highly educated residents. People with genes for high conscientiousness more often moved to affluent suburbs.
• The impression you make. In an American study, interviewers rated participants' personalities after meeting them face to face. Those with genes for low neuroticism and high extraversion, agreeableness and openness were more often seen as having an attractive personality.
• How you answer questionnaires. Genes for neuroticism were linked to fewer answers and more "don't know" and "prefer not to answer" responses. Genes for openness were linked to filling in optional questionnaires. This means personality can affect who takes part in research, even in studies that are not about personality.
• Mental health. Genes for neuroticism were linked to a higher risk of every mental disorder studied, especially anxiety and depression.

Using a method called Mendelian randomization, the researchers also tried to separate cause from effect. The results suggest that personality affects health. Conscientiousness, for example, appeared to lower body mass index and the likelihood of starting to smoke, while extraversion increased the risk of catching COVID.

But it also worked the other way. Education, smoking and weight appeared to affect personality. Personality is not only something our genes give us, but also something life shapes.

Why your DNA cannot predict your personality

The researchers built a genetic score for each trait and tested it in five new groups that were not part of the main analysis. The score worked in every group. But it only predicted a little. Even for extraversion, where it worked best, it explained only a few percent of the differences between people.

The authors say it plainly: the genetic score cannot predict what an individual person will do.

So a DNA test is a long way from replacing a personality test. And it may never get there. Even twin studies show that at least half of the differences in personality are not about genes.

What does this mean for you?

A few things are still worth taking away:

1. Personality is partly inborn. The study confirms with more certainty than before that genes play a real role, and that the link is not just down to the family you grew up in.
2. No single gene makes you shy or messy. The effect of each variant is so small it is barely noticeable.
3. Personality can change. Your genes work together with your life. A meta-analysis of 92 groups followed over time shows that most people become more conscientious and emotionally stable with age.
4. Measurement takes precision. The study shows that noise in personality tests hides real relationships. The more questions a test has per trait, the more precisely it measures you.

Are you like your siblings?

The study rests on a simple idea: siblings share on average half of the genetic variants that make people different, and grow up in the same home. Partners share a home, but not genes. And according to the study, partners are surprisingly unalike in personality.

You can test it on your own family. Take the test, and ask a sister, brother, parent or partner to do the same. With the comparison feature, you can see trait by trait where you are alike and where you differ. You can also create a group and gather the whole family in one overview.

Maybe you and your sister are equally curious but completely different when it comes to tidiness. That is exactly what thousands of tiny genetic nudges and different life experiences would lead you to expect.

Compare yourself with your family

Where do you stand?

Our free Big Five test measures the same five traits as the study, with 120 statements and six facets under each trait. You find out where you stand compared with others, but not how much of it comes from your genes. No test can tell that about one person.

If you want to read more about what genes can and cannot say about a person, we have also written about the analysis of Hitler's DNA.

Take the Big Five test and see where you stand on the five traits the researchers traced in the genome.

Sources

• Roberts, B. W., Walton, K. E. & Viechtbauer, W. (2006). Patterns of mean-level change in personality traits across the life course: A meta-analysis of longitudinal studies. Psychological Bulletin, 132(1), 1–25.
• Schwaba, T., Clapp Sullivan, M. L., Akingbuwa, W. A., … Tucker-Drob, E. M. (2026). Robust inference and correlates from genetic associations with personality. Nature, 658, 1226–1236.
• Vukasović, T. & Bratko, D. (2015). Heritability of personality: A meta-analysis of behavior genetic studies. Psychological Bulletin, 141(4), 769–785.