Chemicals leached from old batteries can cause renal disease. Mercury from coal-fired power plants and carbon monoxide from vehicle exhausts can cause reproductive problems. And this is a much abbreviated list of today’s environmental hazards.
However, some animals adapt to environmental pollutants. Take, for example, a population of Atlantic killifish (Fundulus heteroclitus). These finger-sized minnows, sometimes called mudfish, live in some of the most polluted waters in the country. But these animals managed to survive, even thrive, thanks to some beneficial mutations that allowed them to adapt surprisingly fast to an environment that killed off many other species.
Could what worked for killifish work for humans? Could we, at some point, develop resistance to the chemicals that put us in danger today?
[A] give-and-take aspect of genetic mutations is common. “Many mutations effect numerous traits or aspects of physiology,” says [genetics and biology professor Sarah] Tishkoff, something called pleiotropic effects. Some of the effects are favorable, and some are not. “For example, some of the variants that often play a role in detoxification also play an important role in metabolizing drugs,“ she says.
So you might get a mutation that protects you from absorbing PCBs, but also keeps you from absorbing your life-saving medicines. In other words, evolution is complex.