Like mutation, but rinses out in four generations!

June 4, 2005 11:58 AM

Like mutation, but rinses out in four generations!A new study finds that exposure to high levels of environmental toxins produces epigenetic changes in rats' sperm. "Epigenetics does not involve DNA sequence changes but chemical modification of the DNA." Ultimately, this may help to explain why certain human diseases, such as breast and prostate cancer, are becoming more common. The increase in the incidence of these diseases cannot be accounted for by a normal rate of genetic mutation, but epigenetic damage could be the culprit.
posted by bricoleur (6 comments total)

What a timely post! Straight Dope, inconclusively, tackled the rising cancer rates issue yesterday!
posted by 6550 at 12:25 PM on June 4, 2005

"Cecil's" conclusion:

The message the cancer-prevention crowd harps on is that your chances of getting cancer are largely a matter of personal choice, so don't smoke, exercise regularly, eat less fat and more fiber, etc. While this is surely true, people often worry more about the cancer dangers they don't (or didn't) know about, e.g., lung cancer due to asbestos. What percentage of cancer deaths arise from such insidious threats? Respected UK researcher Richard Doll offered the following estimates in 1998: Ionizing radiation, UV light, 5 to 7 percent; occupational exposure, 2 to 4 percent; air-, water-, and food-borne pollution, 1 to 5 percent. For comparison, tobacco accounts for maybe 29 to 31 percent of deaths and diet 20 to 50 percent. Conclusions: (1) the experts think cancer risk due to smoking and lousy eating habits dwarfs most of the stuff people get paranoid about; (2) expert opinion notwithstanding, given that 30-point spread for diet, many cancer risk estimates barely qualify as educated guesswork.
posted by mecran01 at 5:15 PM on June 4, 2005

What, you mean ingesting poisoned food, breathing poisoned air, and surrounding ourselves with manufactured products made from poisons might be poisoning us?
posted by eustacescrubb at 5:16 PM on June 4, 2005

...ultimately, this may help to explain why certain human diseases, such as breast and prostate cancer, are becoming more common. The increase in the incidence of these diseases cannot be accounted for by a normal rate of genetic mutation, but epigenetic damage could be the culprit.

Do you have any reason to say this? Nothing close to those words appears in the article linked. The study concerns endocrine disrupters effect over several generations mediated by epigenetic factors. Actually epigenetic factors may, or may not be responsible.

Although they don't mutate the DNA sequence of an animal, epigenetic changes can be inherited and affect how genes are expressed. One common epigenetic change is the attachment of methyl groups to DNA, which can shut a gene off or turn it on. Indeed, Skinner's group showed that methylation patterns in the testes of affected rats differed from those in control rats. However, they didn't rule out mutation of the animal's DNA sequence, notes epigeneticist Emma Whitelaw of the University of Sydney, Australia. The changes in methylation might simply correlate with the declining fertility, she says: "I'm not sure it's an epigenetic mark."

posted by euphorb at 8:12 PM on June 4, 2005

bricoleur : interesting.

euphorb: much more interesting.

Thanks to the both of you.
posted by recurve at 8:43 PM on June 4, 2005

Do you have any reason to say this?

From this article, which I should have linked to in the original FPP:

Lead researcher Dr Michael Skinner believes they may contribute to diseases such as breast cancer and prostate cancer.

Both diseases are becoming more common, and Dr Skinner says that cannot be down to genetic mutations alone.
posted by bricoleur at 5:25 AM on June 5, 2005