It wasn't until the 1950s that Oxford University's Bernard Kettlewell conducted a legendary experiment that demonstrated why the black moths had evolved much faster than Darwin thought possible. Over a three-year period, Kettlewell tracked the fates of hundreds of marked moths that he released in two English forests, one by the pristine southwest coast, the other near the polluted metropolis of Birmingham. In the Birmingham woods—a stand-in for the industry-ravaged landscape of the Victorian era—black moths avoided predation by birds because they blended into the soot-stained trees; the white moths, by contrast, were easy to spot and thus became snacks for sparrows. The opposite occurred in the coastal woods: The black moths stood out when they alighted on the light-colored trees and were gobbled up.
Kettlewell's experiment on “industrial melanism” became a staple of high school biology textbooks because it succinctly illustrates how species can, when subjected to intense environmental pressures, evolve in a matter of years rather than over millennia. But the next few generations of evolutionary biologists were less attracted to hives of human commotion like Birmingham. Researchers raised on episodes of Wild Kingdom and the books of Jane Goodall gravitated toward fieldwork in remote places populated by animals they'd never otherwise encounter. Their mentors encouraged them to go abroad because they knew that faculty hiring committees were wowed by the exotic. The road to a tenure-track job ran through the jungles of the Amazon, not the parking lots of Houston or Columbus, Ohio.
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Crispr Will Transform the Way We Eradicate Invasive SpeciesFor the first chunk of his career in evolutionary biology, Jason Munshi-South harbored all the standard romantic notions about which projects he should pursue. He studied the mating habits of tree shrews in Borneo and the demographics of elephants in Gabon, while earning his PhD from the University of Maryland and doing a postdoc at the Smithsonian. But in 2007, Munshi-South became an assistant professor at Baruch College in New York City, shortly after which his first child was born—two events that curtailed his globe-trotting. Restless, he looked for ways to scratch his fieldwork itch within range of the subway. His search for convenient subjects led him to study the white-footed mice that have colonized New York's parks.
Munshi-South and his assistants trapped scores of live mice and clipped off bits of their tails to get genetic material. Financial constraints and the state of technology at the time meant Munshi-South couldn't sequence the animals' entire genomes. Instead he used a shortcut called transcriptome analysis, which centers on the messenger RNA molecules that carry DNA's instructions for protein synthesis into cells. Since only the crucial bits of an organism's DNA get written into messenger RNA, researchers can work backward to infer, with impressive precision, the composition of the genes where it originated.
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