Up until recently, genetic research on personality has yielded few results, but that has changed with the availability of massive datasets for genome-wide association studies.
In a series of papers published since mid-2016, scientists have established promising new findings that rely on vast amounts of data from the likes of the the UK Biobank, the international Psychiatric Genomics Consortium, and 23andMe.
By conducting genome wide association studies — or meta-analyses — with data from hundreds of thousands of people, researchers have found genetic associations where they could not before. In the last year alone, they’ve found associations for such traits as educational attainment, depressive symptoms, neuroticism, and risk-taking behavior.
The success on these fronts has opened up the hunt for more genetic signals associated with psychological and behavioral traits. Scientists are also doubling back on the research over the last year attempting to replicate the findings — when replication was not conducted in the initial study — to ensure the associations are valid.
The Big Five
In July, scientists from St. Louis University, the University of Cambridge and 23andMe zeroed in variants in two genes, CADM2 and MSRA, found to be associated with personality, specifically risk-taking behavior and irritability. The gene CADM2 is important in organizing the synapses in the brain, while MSRA encodes a family of enzymes in the body.
By going back and conducting a replication study, the researchers were also able to broaden the range of traits they looked at, and include additional personality traits beyond the so-called “Big Five” —neuroticism, extraversion, openness, agreeableness, and conscientiousness.
For this replication study, researchers included 19 additional measures to more fully describe the Big Five, adding in data for such things as anxiety, risk-taking, order, altruism, and self-discipline.
The study replicated the associations with a variant in the CADM2 gene for risk-taking, agreeableness, and extraversion. The researchers were also able to replicate the variant in the MSRA gene associated with irritability.
While both exciting and promising, the new findings are also tempered by the hurdles faced by genetic research in general. Just finding the associations is not enough — researchers are still trying to learn more about the genetic architecture and biological mechanisms underlying these complex traits. Also, these associations often have a small effect on the traits. But the findings suggest that with even larger sized studies may offer more insight.
You can read the full replication paper here.