Do you vote Tory or Labour? The answer may lie in your genes!

With Theresa May having called an early election, and the UK gearing up for the polls, I thought I would look at how our genes impact our political decision-making.

In my book, The Genetics of Health (Simon and Schuster), I call dopamine “The Pleasure Particle.” It is much more than that; Dopamine is involved in behaviours that involve risk and reward.

Some studies in the past looked at a gene that is linked to a particular dopamine receptor, DRD4. Previous studies have noted an association between this gene and financial behaviour.

When Richard Ebstein and colleagues at the National University of Singapore studied 1771 Han Chinese students (in a study published in the Proceedings of the Royal Society B) they found a distinct association between political behaviour and the sequence of a particular segment of this DRD4 chromosome. In general, people had either two (2R) or four (4R) repeats.

People with two copies of the 4R version of the gene were found to be significantly more conservative than people with any other combination. And this association was much stronger in females -- of female students who were Tories, 62.5 percent had two copies of the 4R version of the gene; among those that considered themselves to be highly liberal (in an American sense, a likely Democrat), only 37.9 percent had two copies of the 4R version.

But is our political leaning shaped more by nature or nurture? Another study looked at a different variant of the DRD4 gene that had a 7R version. Among people with this seven repeat (7R) version, this study revealed that the number of friendships a person had in adolescence was significantly associated with liberal political ideology. It turns out that the less friends you have as a young adult, the more conservative your views.

A few years ago, there was another study that looked at gender bias and political behaviour. It transpires that our political decision-making is rather shallow – people tend to vote for faces rather than policies. However, there was a gender difference -- in particular, men are more likely to vote for attractive female candidates, whereas women are more likely to vote for “approachable” male candidates.

In genetics, twin studies are a good method of looking at the impact of nature and nurture. Typical twin studies look at twins raised in similar environments, as this helps researchers to specifically look for inherited traits. As Sir Francis Galton once wrote, “Twins have a special claim upon our attention; it is that their history affords means of distinguishing between the effects of tendencies received at birth, and those that were imposed by the special circumstances of their after lives.”

I looked at twin studies in the context of longevity in my book, The Genetics of Health to understand why people live longer in certain places on earth. When it comes to longevity, it seems that nature (genes) accounts for 25% and the rest is controlled by environmental or lifestyle factors. I found a particular twin study of political and social issues interesting as it was a massive study of 30,000 twins (who knew there were so many twins in one area!) and their relatives.

When people specifically looked at political affiliations, as this study of twins in Virginia did in 1999 – they concluded that political conservatism was 64.5 percent heritable in men and 44.7 percent heritable in women. If you were a man, and a Tory, your conservatism was more likely bred into you. If that’s the case, then having a female leader is likely to be more beneficial for a conservative party (and this may explain Margaret Thatcher’s wins, or Hillary Clinton’s losses). Perhaps Corbyn and Labour indeed have a biological reason to be worried.