When we look around Europe to our neighbours, particularly to the ones living in Nordic countries and the Netherlands, we often have to look up to them – literally. With the average Irishman standing 177cm tall (5ft 9½ inches) to the 184cm-tall Dutchman (6ft ½inch), researchers believe that genetic traits, inherited and passed along across millennia of natural selection, might explain why Europeans vary so much in height and weight.
"We found that genetic differences between countries provides an explanation for national differences in height," says Matthew Robinson, from the University of Queensland in Australia. He led a research team of global scientists exploring why Europeans look so different, and published his results earlier this week.
People all around the world, including in different parts of the same continent, display widely varying differences between their height and body mass index (BMI), a ratio of their height to weight. In Europe, Dutch people are, on average, seven centimetres taller than their southern European cousins in Italy, and an extra centimetre taller than the Spanish.
But the role that genetics plays in determining these physical traits, along with how environmental influences have been affecting the body, has not been clear cut, leading to Robinson and his team at the University of Queensland to take on the challenge.
"We were interested in working out whether there were genetic differences," said Robinson.
Genetics by numbers
Using genetic sequence data from nearly 9,500 Europeans across 14 countries, the study gathered predictions of height and BMI statistics. They then checked these for national differences, which would essentially indicate that the genes which influence a person’s height and BMI are more or less common in people from different countries.
"They found that historic natural selection on both height and BMI has created genetic differences among different countries," said a Nature Genetics press release.
The study revealed that there is a stronger genetic link to height than weight, as almost 25% of the variation in height of Europeans could be linked to regional genetics. Less than 10% of BMI variation was associated with BMI, the study claims.
Robinson believes that is mostly likely due to “historic natural selection,” the process described by Charles Darwin where humans and animals best suited to surviving their environments thrive and pass on their genetic traits over time, while weaker creatures ill-suited to the location die off.
"Many thousands of years ago when Europe was being settled, it is likely that the characteristics that were best to survive differed in the Mediterranean as compared to northern Europe," Robinson says.
