REAL LIFE NEWS: EVOLUTION IN ACTION
Research has shown that people whose ancestors come from cities are better suited genetically to fighting infection.
The team from the University of London looked at the numbers of people who carried a gene variant which is known to give them resistance to TB and leprosy. They found it was more common in those from areas with a longer history of urbanization, where the diseases would have been rife at one point.
Reporting in the journal Evolution, the researchers suggest this is an example of "selective pressure" in relation to disease resistant. It happens because people who fall prey to killer diseases are less likely to pass their genes on that those who have some kind of resistance, being likely to die before they have children.
Diseases such as TB are more common in urban areas where people intermingle more closely, so the likelihood of being exposed to infectious diseases is, in theory, higher. Therefore over the centuries, the more likely it is that these resistance genes will spread widely amongst the population.You can read more about how this research was carried out here.