NEW YORK, Feb. 17, 2011 A research group led by a New York University School of Medicine scientist discovered a genetic variant that allows a fish in the Hudson River to live in waters heavily polluted by PCBs. In a study published in the February 18, 2011, online issue of Science, they report that a population of Hudson River fish apparently evolved rapidly in response to the toxic chemicals, which were first introduced in 1929, and were banned fifty years later. PCBs, or polychlorinated biphenyls, were used in hundreds of industrial and commercial applications, especially as electrical insulators.
"We've found evolutionary change going on very quickly due to toxic exposure, and just one gene is responsible for it," says Isaac Wirgin, a population geneticist, associate professor of environmental medicine at NYU School of Medicine, and the study's lead investigator. "There are not many examples of this in the scientific literature."
General Electric released approximately 1.3 million pounds of PCBs into the Hudson River from 1947 to 1976. The Atlantic tomcod, Microgadus tomcod, is a common bottom-feeding fish in the Hudson that is not usually eaten by humans. The fish, which typically reaches a length of 10 inches, had long been known to survive exposure to PCBs, and levels of the chemical in its liver are among the highest reported in nature. However, scientists did not understand the biological mechanism that allowed the tomcod to survive chemical exposures that kill most other fishes.
Dr. Wirgin and scientists at NOAA Fisheries Service in New Jersey and the Woods Hole Oceanographic Institution in Massachusetts spent four years capturing tomcod from contaminated and relatively clean areas of the Hudson River during the winter months, when tomcod spawn in the river. The fish were screened for genetic variants in a gene encoding a protein known to regulate the toxic effects of PCBs, which is called the aryl hydrocarbon
|Contact: Lorinda Klein|
NYU Langone Medical Center / New York University School of Medicine