More Evidence of Environmental Factors Influencing Evolution

Air pollution causes sperm mutations

"The mice, reared in cages kept in a shed downwind of two steel mills and a busy highway in a Canadian city, showed a host of genetic changes compared to similarly housed mice breathing filtered air. DNA in the sperm of the mice in the polluted area contained 60% more mutations, had more strand breaks, and had more bases that had been chemically modified via the addition of a methyl group. That modification, called DNA methylation, can affect whether a gene is expressed."

http://www.nature.com/news/2008/080113/full/news.2008.439.html