Subjected to the unusual pressures of the urban landscape in New York City, the white-footed mouse has been evolving to survive, evolutionary biologist Jason Munshi-South said at this month's Secret Science Club.
The urbanization of New York City has changed the local environment and its ecology in several ways: species diversity has declined and some species (like rodents) have undergone population booms. Diversity has been lost because nature has been compressed into the small green areas left. The researchers guessed that over time, these changes will kill off some species, and push others to evolve.
While some species have become rare, or even suffered local extinctions, others like the white-footed mouse are very dominant. Munshi-South said that if 100 traps were set up in NYC you would get about 50 mice in one night, where as outside of the city you would only catch about 10.
Using the white-footed mouse as a model for urban evolution, Munshi-South collected 25 samples from 15 different parks in NYC, and sequenced 18 of their genetic markers. He found the mice have been isolated enough to develop different genes in different areas of the city.
Genetic drift, or the introduction of different genes into new populations, is basically zero in New York City. This, along with natural selection and adaptive genomics, has probably allowed these mice to live longer, have more offspring, a heartier immune system, and all-in-all, survive better in these urban areas.
Using DNA from old mouse specimens, Munshi-South hopes to see how exactly these mice have changed, and how they have adapted to an urban environment.
Several other urban species are also adapting to these urban pressures. See our slideshow of urban animals running wild in our cities >