Professor Researches NYC Rat Diet

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Jason Munshi-South, associate professor of boiology, studies the effects of urban variables on white mice (Courtesy of Flickr).

By Helen Stevenson

Jason Munshi-South, associate professor of biology, studies the effects of urban variables on white mice (Courtesy of Flickr).

Living in New York City means eating a lot of pizza – even if you are a mouse. Jason Munshi-South, associate professor of biology at Fordham University, studies the impact that an urban setting has on the genetic makeup of mice.

“Previous results showed that white-footed mice in NYC parks have become genetically differentiated from each other over time, primarily because they are a native species that are not able to travel through the built environment,” said Munshi-South. “We then thought it would be interesting to see if these mice are adapting to local urban conditions.”

To conduct his research, Munshi-South captured and sequenced about 24,000 genes from 48 mice that were sampled from three urban and three rural populations. One of the locations that he used in his study was the native woodlands at the New York Botanical Garden, just across the street from Fordham University’s Rose Hill campus.

Munshi-South then used computational analyses to identify and compare the genes that were very different between the urban and rural populations of mice.

“These techniques identify differences that are much stronger between urban and rural mice than one would expect from random changes over time, indicating that these genes have been impacted by natural selection in NYC,” said Munshi-South. “After identifying the genes, we compared the sequences to the lab mouse genome to identify the functions of these genes under selection.”

According to New Scientist, the research focused on genes in urban mice that are linked to non-alcoholic fatty liver disease, a condition that may arise from increased consumption of fatty acids. One of the 24,000 genes found is used to produce omega-3 and omega-6 fatty acids. Another was found to be associated with indigestion and other metabolic processes.

“This finding leads us to believe that urban white-footed mice are consuming a very different diet than mice in rural forested areas,” said Munshi-South.
“One possibility is that the urban mice are consuming human food waste. Another possibility, which I think is more likely, is that the availability of plants and insects in urban areas is different than in rural areas. Urban mice may actually consume a better diet than their rural counterparts, who have to deal with many more competitor species,” he said.

Regarding the research, Munshi-South was not too surprised that there were discrepancies in genes related to the immune system or dealing with toxins due to the pollution and increased exposure to disease in NYC.

However, Munshi-South said, “We were surprised at how many genes involved in lipid and carbohydrate metabolism came out as candidates for selection.”
Munshi-South has studied the evolutionary responses of wildlife to urbanization for about 10 years. In a matter of just a few generations, he has witnessed the change in species in response to the urbanization around urban animals, such as the NYC mouse.

“These findings indicate that rapid evolution driven by human activity and environmental change is happening right under our noses,” he said. “Such changes are likely to be occuring in a number of species in NYC.”