SSS 2008-02-01（在线收听）

This is Scientific Americans' 60-Second Science. I am Cynthia Graber. This'll just take a minute.

Air pollution is bad for our health, but scientists say we don't know much about the long-term effects. So researchers in Canada and the Netherlands decided to gather genetic information in an urban industrial environment by looking at mouse sperm. They published the study in the Proceedings of the National Academy of Sciences. The scientists placed cages of mature male mice near two steel mills and a major highway in the city of Hamilton, in Ontario, Canada. Some of the mice breathed in ambient, particulate-filled air. The control mice breathed pure, filtered air. After ten weeks, researchers checked the two groups. The mice exposed to the polluted air had a 60 percent higher rate of sperm mutation. It occurred in a piece of DNA particularly susceptible to mutation. Researchers say these specific mutations are known to affect gene expression and genome stability and could lead to changes in genetic composition and disease. They say they can't yet extrapolate from these findings to the long-term health effects in humans, but they say the results definitely warrant a more detailed look at pollution's effects on our genes.