The citizens of nations which rate themselves happiest display a specific genetic feature: their DNA is more likely to contain a specific allele involved in sensory pleasure and pain reduction, say Michael Minkov of the Varna University of Management (formerly International University College) in Bulgaria, and Michael Bond of the Hong Kong Polytechnic University. They weighed up genetic and various external factors to might contribute to national differences in happiness. The findings are published in Springer's Journal of Happiness Studies.
