Re: Air Pollution Could Shrivel Sperm's DNA

January 16, 2008

Air Pollution Could Shrivel Sperm's DNA

By Keim, Wired Magazine. _tinyurl.com/ytjhpo_

As if the damage of foul air to our lungs wasn't bad enough, scientists have

found another way for smog to harm people: by wreaking genetic havoc in men's

sperm.

In a study published Monday in the Proceedings of the National Academy of

Sciences, a team of Canadian geneticists put open-air cages of male mice

downwind of steel mills and beside a highway. A second group of mice were

placed

beside them in cages outfitted with air purifiers.

After a couple months, the researchers compared the mice. Sperm from the

industrial group, they found, had half again as many genetic mutations as sperm

from HEPA-breathing counterparts. The polluted sperm was also

hypermethylated, meaning that genes were being turned on and turned up more

than they should

have been.

Though mice aren't people, the findings do point to a plausible mechanism by

which air pollution could affect humans. Mutations in so-called germline DNA

" may cause population-level changes in genetic composition and disease, " the

researchers wrote. " Changes in methylation can have widespread repercussions

for chromatin structure, gene expression and genome stability. Potential

health effects warrant extensive further investigation. "

The paper comes out at an opportune time: while President Bush's 2003 Clear

Skies Act died in committee, individual provisions were later enacted. These

slowed -- even reversed -- a federal crackdown on power plant pollution, and

the Bush Administration was criticized for ignoring studies it commissioned

on the dangers of failing to reduce mercury pollution. Meanwhile, the

Environmental Protection Agency has been involved in a running battle over its

sometimes-weak clean air enforcement.

Clean air takes on even more significance if it becomes an issue of genetic

health. One possible line of questioning: could rising pollution levels cause

the sort of sperm mutations recently identified in parents of some children

with autism? I sent the question to the researchers from this study, and will

let you know what they say.

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