LONDON – Human evolution may be winding down as the forces that once drove it – older fathers, isolated populations and widespread child mortality – are disappearing, a geneticist at the University College London argues.

In a lecture this week titled “Human Evolution is Over,” genetics professor Steve Jones said the rate of genetic mutations found in humans is falling dramatically, something he believes is largely the result of lifestyle changes.

Powerful men who once fathered dozens or hundreds of children, often into their 60s and 70s, have given way in most developed parts of the world to younger fathers who tend to sire just a few children in their 20s and 30s. Because older fathers are more likely to pass on genetic mutations, the rate of those mutations entering the population has declined, he argued.

Similarly, child survival rates, abysmal in antiquity, have dramatically improved in much of the world, cutting natural selection pressures. And the world’s increasingly huge, mobile population has nearly eliminated the possibility of unusual genetic traits taking hold in isolated populations, he said.

That’s good news for those who like the human race just as it is, though perhaps bad news if humans need to evolve to meet some unexpected challenge down the road, the science – as yet not backed up by other research – suggests.

The other good (or perhaps bad) news? Genetic mutations caused by growing chemical and radiation exposure may take over where older fathers left off, Jones said.

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AP-NY-10-11-08 2100EDT