The State of New Jersey says you can’t eat the fish or shellfish from the Lower Passaic River and Newark Bay. That’s because they’re living in theDiamond Alkali Superfund Site, where toxic leftovers from the manufacture of chemicals like DDT and the infamous Agent Orange oozed into surrounding waterways to be taken up by the animals that inhabited them. It’s an evolutionary miracle some of these animals are even alive. No, seriously. A fish that adapted to survive in this water shows evolution at its finest, according to a study published Thursday in Science.
The Atlantic killifish is a slippery sliver of silver about the size of a fat finger and as common as the minnow. Starting in the late 1990s, researchers became aware that the fish was tolerant of the toxic waters at the Lower Passaic Superfund site and at least three other highly polluted areas along the Atlantic coastline. The new study found that over just a few decades, distinct populations of killifish independently developed similar genetic adaptations that make life possible in the most unlikely environments. The findings show that evolution doesn’t have to start in one place to be repeated.
“It’s these shared changes as well as the unique pattern of changes in these different populations that provide us with a really useful field example of how animals can respond to rapidly changing and extreme environments,” said Diane Nacci, a biologist at the Environmental Protection Agency who worked on the study.
She and other researchers, led by Noah Reid, an evolutionary geneticist at the University of Connecticut, compared the whole genomes of 384 killifish from these areas and nearby, less-polluted waters. They found that in all regions, one particular genetic pathway was the source of the pollution tolerance, although slightly different patterns of genetic changes were responsible in each population.