City dwellers develop genes to fight off disease
City living is no day in the park for hypochondriacs. Between coughs in the subway and close contact with people, germs are ubiquitous and unavoidable. As a New Yorker, I like most Americans have become accustomed to the urban lifestyle.
If trends continue, much of the world will, too: About 60 percent of people will live in cities by 2030.
Hello, mega cities and their problems.
People who live in cities are more likely to be exposed to infectious diseases. While individually this is bad, as a whole everyone is better off because over time the population builds up resistance to bugs (even if you need to sacrifice your life).
The gene defect that causes the lung disease cystic fibrosis might be seen as a bad thing. However, cystic fibrosis might have helped them fight the cholera toxin. So evolutionarily speaking, cystic fibrosis might be been a good thing back then.
Researchers at University College London and the University of London looked specifically at gene variants known to give a person resistance to deadly diseases like tuberculosis and leprosy.
British researchers checked the DNA of people from 17 countries. The researchers also checked historical records of the cities.
The gene variants for TB and leprosy were found in Middle Eastern and Europe cities, but weren't present in regions like Africa.
Urban living helps people build resistance. This selective pressure might explain some of the other types of disease resistance observed, like in the case of cystic fibrosis.
An Imperial College London professor told the BBC:
Individuals who are more resistant to a pathogen that causes a disease with substantial mortality, such as malaria or TB, will survive better and will contribute more offspring to the next generation.
This post was originally published on Smartplanet.com