Healthy living

City living boosts immunity to disease

City living Evolution in action

People whose families have long lived in urban areas may be more resistant to some infectious diseases, scientists claim.

UK scientists have discovered a gene variation more commonly found in populations with a long history of urbanisation. The gene variant reduces the chances of becoming infected with diseases such as tuberculosis and leprosy.

In ancient cities, the combination of poor sanitation and dense population would have been an ideal breeding ground for germs and the spread of disease.

But the study, published in the journal Evolution, suggests that past exposure to such infectious diseases has led to disease resistance in populations, which is then passed on to descendents.

A team of UK scientists analysed DNA samples from 17 different human populations living across Europe, Asia and Africa. They then compared the rates of genetic disease resistance with urban and archaeological records.

The scientists found that people living today in areas with a long history of urban settlements are more likely to possess the DNA variantion which gives some resistance to infection.

The results also showed that the protective gene variant is found in nearly everyone from the Middle East to India and in parts of Europe where cities have been around for thousands of years.

Dr Ian Barnes at the Royal Holloway, University of London, said: “This seems to be an elegant example of evolution in action. It flags up the importance of a very recent aspect of our evolution as a species, the development of cities as a selective force.

"It could also help to explain some of the differences we observe in disease resistance around the world.”

The research was carried out by scientists from the Royal Holloway, University of London, University College London and Oxford University.

This article was published on Mon 27 September 2010

Image © Dmitry Nikolaev -

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