Your inclination towards taking a gamble and whether or not you can keep your cool if you lose are both partly influenced by your genes, according to two new studies. The two research teams, from the UK and Germany respectively, each identified a gene variant that affects an individual's risk-taking behaviour or their temper. Interestingly, both character traits were associated with differences in the activity of the same area of the brain, the amygdala, which is responsible for processing and regulating emotions.
The UK researchers, from University College London, focused on a gene called 5HTTLPR, which has two variants called 'long' and 'short' and is known to affect the response of the amygdala. The 5HTTLPR gene encodes a protein that controls the transport of serotonin, a chemical in the brain that is essential for communication between nerve cells and has an important role in mood regulation.
The researchers found that individuals with two copies of the 'short' 5HTTLPR gene were less consistent with their decision making and were more likely to take risky gambles in certain circumstances compared to those with two copies of the 'long' 5HTTLPR gene. In particular, those with two 'short' genes were more susceptible to what is known as the 'framing effect' - phrasing a gambling choice to make it sound more attractive. For example, they were more likely to accept the same gamble if it was put in a positive way (such as, 'you have 40 per cent chance of winning'), than if it was put in a negative way ('you have a 60 per cent chance of losing').
The UK study, published in the Journal of Neuroscience, also found that those with two 'short' genes had greater signs of brain activity in their amygdala when making 'framed' decisions compared to those with two 'long' genes.
In the German study, published in the journal Behavioural Brain Research, the researchers examined a variation within a gene called DARPP-32. DARPP-32 affects levels of another brain chemical called dopamine, which influences feelings of anger and aggression. The researchers, from the University of Bonn, asked 800 volunteers to fill in a questionnaire to assess how they handle anger and performed DNA tests to determine which variant each volunteer carried. They found that those with one or two copies of the 'T' variant were significantly angrier in disposition than those without. These angry individuals also had less grey matter - brain tissue that contains active nerve cell bodies - in their amygdala.
The authors of both studies were keen to emphasise that with behavioural traits, genes can only ever be part of the story, with external social and cultural influences also playing an important role. Professor Martin Reuter, who led the German team, said: 'You can modify your personality within the range given to you by nature'.