Ethnicity

The results of a study on race, reported in the Times, are very much contrary to received opinion:

Races have evolved away from each other over the past 10,000 years, according to new research that challenges standard ideas about the biological significance of ethnicity.

A genetic analysis of human evolution has shown that rather than slowing to a standstill it has speeded up, with different pressures on different populations pushing racial groups further apart. Scientists behind the findings suggest that European, African and Asian populations grew genetically more distinct from each other over several thousand years, as their environments took them down different evolutionary paths.

This would call into question the popular scientific view that race has little or no biological meaning, as the genetic similarities between ethnic groups greatly outweigh differences.

While this remains true – all humans share more than 99 per cent of their DNA – the new work indicates that variations tend to differ between races, and that these became more, not less, pronounced...

The research is published in the journal Proceedings of the National Academy of Sciences. If the trend towards increasing genetic diversity were to continue, it could lead ultimately to the development of different species. Most scientists, however, think this is now highly unlikely.

The research identified evolutionary currents only in past times. In the modern era, greater movement and gene flow between the continents has probably slowed or even reversed patterns of increasing genetic difference, making the evolution of separate human species virtually impossible.

Armand Leroi, Reader in Evolutionary Biology at Imperial College, London, said: “In principle, this could have led to speciation if it had continued. In practice, it has got to be the case that that cannot happen now. The reason is that this study has looked at largely separated populations in the past, but everything about human history since the Industrial Revolution weighs overwhelmingly against separation and thus against speciation too. Huge increases in gene flow are going to wipe this trend out.”

The study shows that over the past 5,000 years, new genetic variants have been emerging at a rate 100 times faster than in any other period of human evolution.

If this rate were to have remained the same since humans and chimpanzees diverged around six million years ago, the genetic difference between the two species would be 160 times greater than it is.

The scientists said this reflected the great increase in human populations over that period, which has allowed more beneficial mutations to emerge. Changes in the human environment, particularly the rise of agriculture, also created new selective pressure to which humans adapted.

If true, this suggests that Steven Pinker may have been prescient in his answer to the Edge question last year about dangerous ideas which may be true: "Groups of people may differ genetically in their average talents and temperaments". Also, of course, it's impossible to read this without thinking of the IQ debate, especially after James Watson's recent unfortunate remarks.

As it happens Malcolm Gladwell has an excellent article on that vexed subject in the latest New Yorker. It needs to be read in full really, but his final sentence sums it up: "I.Q. measures not just the quality of a person’s mind but the quality of the world that person lives in".

This is one debate that isn't going to go away.