Mick Hartley

I wonder how much Steve Jones believes this, and how much he's just stirring it up to get some headlines:

Human evolution is grinding to a halt, according to a leading genetics expert.

The gloomy message from Professor Steve Jones is: this is as good as it gets.

Prof Jones, from the Department of Genetics, Evolution and Environment at University College London, believes the mechanisms of evolution are winding down in the human race.

At least in the developed world, humans are now as close to utopia as they are ever likely to be, he argues. Speaking at a UCL Lunch Hour Lecture in London, Prof Jones said there were three components to evolution – natural selection, mutation and random change.

He said: "In ancient times half our children would have died by the age of twenty. Now, in the Western world, 98% of them are surviving to the age of 21. Our life expectancy is now so good that eliminating all accidents and infectious diseases would only raise it by a further two years. Natural selection no longer has death as a handy tool."

Mutation rate was also slowing down, he said. Although chemicals and radioactive pollution could cause genetic changes, one of the most important mutation triggers was advanced age in men. "Perhaps surprisingly, the age of reproduction has gone down – the mean age of male reproduction means that most conceive no children after the age of 35," said Prof Jones. "Fewer older fathers means that if anything, mutation is going down."

Random alterations to the human genetic blueprint were also less likely in a world that had become an ethnic melting pot, according to Prof Jones.

He said: "Humans are 10,000 times more common than we should be, according to the rules of the animal kingdom, and we have agriculture to thank for that. Without farming, the world population would probably have reached half a million by now – about the size of the population of Glasgow.

"Small populations which are isolated can change – evolve – at random as genes are accidentally lost. Worldwide, all populations are becoming connected and the opportunity for random change is dwindling. History is made in bed, but nowadays the beds are getting closer together. Almost everywhere, inbreeding is becoming less common. In Britain, one marriage in fifty or so is between members of a different ethnic group, and the country is one of the most sexually open in the world. We are mixing into a global mass, and the future is brown."

He added: "So, if you are worried about what utopia is going to be like, don't; at least in the developed world, and at least for the time being, you are living in it now."

Why utopia should depend on continued human evolution he doesn't explain - there is, after all, such a thing as cultural evolution, which is how most if not all utopians, as well as meliorists, have expected things to improve - but I think this is more of a rhetorical flourish than an argument.

As for the rest, well, Johnjoe MacFadden at CiF takes issue by arguing that the future of human evolution now belongs to gene therapy. That's no doubt a point worth making, but you could surely dispute elements in Jones's basic thesis. So, yes, better health and modern medicine mean that natural selection's role is reduced, but this also means that minor mutations, which might previously have died out, can now go on to breed, and thereby contribute to genetic diversity.

Fewer older men becoming fathers…well, I don't know if he has figures to back his point but it seems implausible given that one of the major trends in advanced societies now is for people, both men and women, to put off having children until later in life. For most of human history people bred early and died early.

But the main omission from Prof Jones' analysis, surely, is sexual selection. Darwin himself argued for the importance of this – the peacock's tail factor – and it's become acknowledged now as a vital element in evolution. So yes, in a sense there's bound to be some of the homogenisation that Jones talks about: "the future is brown". And with increased communication there's little chance of a sub-group splitting off and forming a new species, until, sci-fi style, we start heading off into space. But there's the whole element of sexual selection, or, to put it in more specifically human terms, the interaction between culture and biology, which he's left out of the equation, and which is where changes that we can't predict are going to be happening.