Britain's Prime Minister David Cameron with EU leaders in Brussels
Britain's Prime Minister David Cameron (C), Finland's Prime Minister Alexander Stubb and Denmark's Prime Minister Helle Thorning-Schmidt (R) arrives for family photo session at the European Union Reuters

We all have our share of up's and down's, a few smiles and some sorrow and we know we are, if not a very happy lot at least we are a happy lot. But back in Denmark, the scenario is quite different; they are all smiles and no worry. The world has always envied their happiness quotient as the nation has always topped polls of the world's happiest people. Last year they were declared again as the world's happiest nation and Denmark made a place at the top in the World Happiness Report from the United Nations.

Curious researchers decided to find the reason for the Danes happiness. A recent study conducted by the University of Warwick revealed that their happiness mantra was hidden in their genes. Danish genes were correlated to the joy they felt; it was also found that their ancestors were equally happy and optimistic about life.

Researchers looked at the survey data of 131 countries, while Norway, Netherlands, Switzerland and Sweden followed Denmark in the ranking, Togo was seen to be the world's most miserable country. They found that Danish birth was linked to a specific gene that affected brain levels of mood chemical serotonin. Strangely those countries genetically closer to the Danes were also happy.

Economist Dr Eugenio Proto, from the University of Warwick's Centre for Competitive Advantage in the Global Economy (Cage), explained, "We looked at existing research which suggested that the long and short variants of this gene are correlated with different probabilities of clinical depression, although this link is still highly debated."

Shorter versions of the gene result in depression, lower life satisfaction and neuroticism. The Danish have the lowest level of people who possess the short version. "Our research adjusts for many other influences including Gross Domestic Product, culture, religion and the strength of the welfare state and geography," said Dr Proto.

It was however, the gene that caused the unbridled joy. Serotonin is a neurotransmitter that helps to relay nerve signals. A high level of the neurotransmitter can result in greater happiness levels and vice versa, the drug Ecstasy is seen to boost the level of serotonin.

Co-author Professor Andrew Oswald said, "The evidence revealed that there is an unexplained positive correlation between the happiness today of some nations and the observed happiness of Americans whose ancestors came from these nations, even after controlling for personal income and religion." This suggests that those who are even remotely related to the Danish genes are affected by it causing happiness.

This study involved three kinds of evidence and discovered that genetic patterns may help researchers to understand international well-being levels.

'More research in this area is now needed and economists and social scientists may need to pay greater heed to the role of genetic variation across national populations,' said Oswald.