City mouse or country mouse? I collect mice from Philly homes to study how they got so good at urban living

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Megan Phifer-Rixey, Drexel University

(THE CONVERSATION) Dusty barns, gleaming stables and damp basements. These are all places where you might find a house mouse – or a member of my research team.

I’m an evolutionary biologist, and my lab at Drexel University studies wild house mice. With help from Philly residents, we are collecting mice from high-rises and row homes to learn more about the impacts of city living on house mice. In short, we want to know whether there is any scientific basis to “The Town Mouse and the Country Mouse” fable in which the cousins eat differently based on where they live.

Cities are hotter and they have a lot of people living in high densities, which means more trash and usually more pollution. This can affect how species that live in cities evolve. Cities are also dominated by artificial habitats such as sidewalks, high-rises and subways rather than open fields and forests.

We are interested in many possible changes, but especially in whether the many differences between urban and rural environments translate into genetic differences between city mice and country mice, such as which versions of genes related to metabolism are more common.

To find the answers, we sequence the mice’s...