Your willingness to take risks is written in your genes

By examining the DNA profiles – the genetic material – of more than a million people, an international team of researchers has succeeded in identifying 124 genetic variants significantly prevalent in people who live risky lives.

The study was recently published in the scientific journal Nature Genetics – and it is the most extensive DNA-based mapping of potential links between our DNA and risky behaviours undertaken to date.

The DNA that tells the story comes from two sources: British research database UK Biobank and American 23andMe, a company that deals directly with consumers and earns a living by preparing personalised DNA profiles with information such as ancestry and certain basic health conditions. These profiles are based on a saliva sample which the consumer sends to the company.

To investigate potential links between DNA and risk-taking behaviour, the research team compared the DNA details of each of the more than one million participants with information he or she provided in response to a questionnaire.

Each participant was asked to answer yes or no to this question: Would you describe yourself as someone who takes risks? They were then asked about:

Tendency to drive too fast.
Number of sexual partners.
Alcohol consumption, and whether they had ever been a smoker.

The scientific article does not specifically address the issue of compulsive gambling.

A glimpse into the machine room
The scientific article indicates that participants who described themselves as highly prone to taking various types of risk:

Statistically had a significantly high incidence of 124 genetic variants compared to the participants who did not consider themselves especially prone to risk-taking.

Does this mean that the research team has found an on-off switch for certain types of risky behaviour? For instance, an almost irresistible urge to smoke, even though it is extremely unhealthy? Or an equally intense compulsion to drive far too fast?

‘No, it’s not quite as simple as that. But we got a glimpse into the machine room – into human DNA – associated with risky behaviours. And we haven’t had this before,’ says Tune H. Pers, Associate Professor and Lundbeck Foundation Fellow at the NNF Centre for Basic Metabolic Research at the University of Copenhagen and Denmark’s Statens Serum Institut (SSI).

Tune Pers specialises in statistical analysis of huge volumes of biochemical and DNA data, and he and PhD student Pascal Timshel make up the Danish contingent of the international research team responsible for the article in Nature Genetics.

The question of potential links between risky behaviours and human DNA has long intrigued scientists – as well as economists dealing with investment strategies. However, up to now, progress has been slow in identifying the human genes which may be involved:

‘A couple of genetic variants have previously been mentioned as potential candidates. And, of course, we looked at these in our study, but we weren’t able to associate them with a willingness to take risks. Unlike the 124 genetic variants we deal with in the article in Nature Genetics,’ says Tune Pers.

He emphasises that pronounced willingness to take risks cannot solely be explained by genetics:

‘A number of other factors will also play a role, such as cultural or environmental influences. Furthermore, genetic risk markers, such as the 124 genetic variants we have identified, may be weighted differently from one person to the next. If you inherit a genetic variant from one of your parents it will have less weight than if you’d inherited a version of it from both your mother and your father. For this reason alone, it’s difficult to draw more general conclusions about the links between genes and risky behaviours.’

If you ask Tune Pers how many different genetic variants we can assume play a role in risky behaviour, his answer is:

‘I don’t think we can give a definite answer to that. Because what is risky behaviour? In our study, we defined it by asking questions about general risk tolerance but also about respondents’ attitude to tobacco and alcohol. But what if the questions concerned extreme life or death situations and were put to servicemen who’d been involved in violent battles? In such cases, it could easily be that the DNA constituent of risk tolerance would prove to involve genetic variants other than the 124 we’ve looked at so far.
But I don’t think there’s any doubt that genetics are involved in some way or other.’