Mice DNA harmed by soot
THE ASSOCIATED PRESS,
May 14, 2004
WASHINGTON - Sooty air pollution can cause genetic damage that can be
passed along to offspring, Canadian researchers report in a study on
Follow-up work is needed to learn if people can inherit
pollution-damaged DNA that harms their health. In the meantime, the
discovery is sure to increase scientists' worry about particulates, the
microscopic soot particles emitted by factories, power plants and
diesel- burning vehicles.
"The new work now adds another area of potential concern" because of
the implications for risks to future generations, said Dr. Jonathan
Samet of Johns Hopkins University, who headed a recent National Academy
of Sciences call for more research into the dangers of this common
These airborne particles are linked to a growing list of health
problems, including asthma and heart disease, in those who breathe high
levels of them.
But there had been little evidence that any air pollutant might cause
the kind of genetic damage that can be inherited - until Canadian
scientists in 2002 housed mice downwind from steel mills and tested
their offspring. The males passed on double the DNA mutations as mice
living in the cleaner countryside.
The question was why.
Now those same researchers, from McMaster University in Ontario, report
today in the journal Science that they've found the culprit: airborne
particulate matter, better known as soot.
In the new experiments, biologist James Quinn and colleagues housed two
groups of mice near the steel mills for 10 weeks. One group breathed
outside air, while the other was housed in a chamber equipped with HEPA
filters - high-efficiency air filters designed to catch microscopic
Then, the mice were bred and their offspring checked for specific DNA
mutations that are passed through the father's sperm.
Mice that breathed filtered air had mutation rates 52 percent lower
than mice exposed to full-strength steel mill pollution.
The specific sperm changes measured aren't linked to disease, but
they're similar to a type of DNA damage that is. Quinn said more study
is needed to see if they're a marker for potential health problems, and
whether pollution-spurred mutations in disease-causing genes could be
The Environmental Protection Agency already has ordered tougher curbs
on ultra-fine particulate pollution because of concern about effects on
the elderly, children and people with respiratory illnesses. In
December, it plans to reveal which parts of the country aren't in