Pollution 'could kill off human race'

Published on 11/05/2006 00:28

POLLUTION is far more damaging to humans than originally thought and is causing genetic mutations which could eventually wipe us from the face of the planet, according to a leading scientist.

Dr Laurence Loewe, of the Institute of Evolutionary Biology at Edinburgh University, said researchers had under-estimated the threat from small but damaging mutations of DNA caused by pollutants such as exhaust fumes and chemicals.

Although these might not immediately cause disease, as they build up over generations they can reach the point within a population where more and more people become infertile and, ultimately, the group dies out.

Most experts had believed small mutations were irrelevant as they did not cause disease.

But, according to a mathematical model of the way they affect populations, there is a real danger from the accumulation of such defects, and this could already be affecting some endangered species.

Dr Loewe said: "Previously, we thought all these small mutations did not matter. The medical community would say, 'If it doesn't add up to a disease, we won't care'.

"The evolutionary community would say, 'Deleterious mutations are going to be removed by selection, so we don't care'.

"But if you keep accumulating more and more [damaging mutations], some years down the line, the overall quality is so much worse."

Humanity cannot rely on natural selection to deal with minor alterations to DNA.

"If the effects are very, very small, this is under the radar of [natural] selection," Dr Loewe said.

This means pollution is gradually degrading the evolutionary fitness of humans and other animals, which could in "millions of years" lead to the end of humanity "given that all the other doomsday scenarios don't happen first", he said.

Dr Loewe carried out a study of the way genes mutate among a population of fruit flies and a paper detailing his work was published by the Royal Society earlier this month. While the study was carried out among flies, the mathematical distribution of mutations should apply to most animals.

Dr Loewe said the results of his study produced the "strong conclusion" that action should be taken to limit the amount of pollution getting into the environment.

"We should reduce the man-made increase of spontaneous mutation rates that frequently comes from environmental pollution by various chemicals," he said.

"If you start to consider how we are living in the West today, there is an incredibly large number of mutagenic things we do because they are part of civilisation.

"There are occasions where we should have it because it's a lesser evil, but it is a complicated topic."

Last year, a study funded by the United States government found that air pollution from vehicle exhausts and power plants appeared to be able to cause genetic changes that have been linked to cancer in foetuses.

So-called "small particles" in exhausts can travel for hundreds of miles in the air and, when breathed in, cause damage to the lungs.

A Canadian study in 2004 found that mice exposed to similar air pollutants saw an increase in the rate of genetic mutation.

Chris Hunt, director-general of the UK Petroleum Industry Association, said the association would be interested in looking at Dr Loewe's research.