( The science has long been clear that s...)Cigarette smoke alters DNA in sperm, genetic damage could pass to offspring

The science has long been clear that smoking causes cancer, but new research shows that children could inherit genetic damage from a father who smokes.

Canadian researchers have demonstrated in mice that smoking can cause changes in the DNA sequence of sperm cells, alterations that could potentially be inherited by offspring. The results of their study are published in the June 1 issue of Cancer Research, a journal of the American Association for Cancer Research.

“Here we are looking at male germline mutations, which are mutations in the DNA of sperm. If inherited, these mutations persist as irreversible changes in the genetic composition of off-spring.” said Carole Yauk, Ph.D., lead author of the study and research scientist in the Mutagenesis Section of Health Canada’s Environmental and Occupational Toxicology Division. “We have known that mothers who smoke can harm their fetuses, and here we show evidence that fathers can potentially damage offspring long before they may even meet their future mate.”

Males, whether they are mouse or man, generate a constant supply of new sperm from self-renewing spermatogonial stem cells. Yauk, along with colleagues at Health Canada and McMaster University, studied the spermatogonial stem cells of mature mice that had been exposed to cigarette smoke for either six or 12 weeks to look for alterations in a specific stretch of repeated portions of DNA, called Ms6-hm, which does not contain any known genes. The “smoking” mice were exposed to two cigarettes per day, the equivalent – based on blood levels of tobacco by-products – of an average human smoker, according to research previously published by one of the study's co-authors.

Yauk and her colleagues found that the rate of Ms6-hm mutations in the smoking mice were 1.4 times higher than that of non-smoking mice at six weeks, and 1.7 times that of non-smoking mice at 12 weeks. “This suggests that damage is related to the duration of exp
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Source:American Association for Cancer Research