New York's rats are genetically distinct, possessing distinct DNA patterns depending on where they live, a new study has revealed.
The study involved sequencing the DNA of trapped Manhattan rats and mapping their genetic profiles.
Uptown rats were found to be genetically distinct to Downtown rats, and even different neighborhoods like the East and West Village had their own distinct rat populations.
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Left: Map of Manhattan showing two genetically distinct clusters of Uptown (black, north of 59th street) and Downtown (white, south of 14th street) rats. D: Estimated migration rates of rats in Manhattan
Midtown Manhattan, however, did not have its own genetically distinct population, likely because the area is less residential and so has fewer household trash sources.
The ultimate goal of the study was to help manage New York City's rat problem as they can spread disease, and some estimates place the city's rat numbers at 2 million - about 20 per cent of New York's 8.4 million human population.
The new study, led by Fordham University graduate student Matthew Combs, involved studying brown rats (Rattus norvegicus) across the island of Manhattan in New York City.
According to the researchers, rats likely invaded the southern trip of Manhattan between 1750 and 1770 , after being introduced by Europeans crossing on ships.
To learn more about the genetic profiles of New York City rats, researchers based at Fordham University trapped rats in various locations in Manhattan.
They used lethal traps and collected tail tissue samples of the rats to sequence their DNA.
The researchers also recorded where the rats were caught, and information about their location, sex, weight and sexual maturity.
They collected 393 samples overall, of which 288 were chosen for sequencing that maximized geographic coverage.
The results of the study revealed a clear split between Uptown and Downtown genetic groups.
The results also showed that rats don't tend to move farther than 1,400 meters (4593 feet) away from their colonies.
This information could be useful for New York City pest managers, as they could focus on aiming to eradicate rat units of this size to limit reinvasion by rats that disperse themselves.
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