Famous UCL geneticist
Steve Jones is being quoted in various places as saying that human
evolution has
stopped:
Health, birth control and the healing power of lust all conspire to tell us that, at least in the developed world, and at least for the time being, evolution is over. So, if you are worried about what Utopia is going to be like, cheer up - you are living in it now.
Jones isn't the first to argue that human evolution has stopped;
Francis Collins has also done so, albeit primarily for religious reasons. It's an interesting claim. There is a large amount of evidence suggesting that humans have been evolving a fair bit recently (recent being the last few thousand years). There have been a few studies taking a general look at evidence for recent positive selection. For example:
Wang, E.T. et al. (2006) Global landscape of recent inferred Darwinian selection for Homo sapiens.
PNAS, 103, 135-140.
and
Voight, B.F. et al. (2006) A Map of Recent Positive Selection in the Human Genome.
PLoS Biology, 4, e72.
As I say, these take a wider perspective, looking at the whole of the genome. There is also research that focuses in much more specifically, on a gene or two, related to a particular trait. The
Lahn lab has been at the forefront of this, for example with evidence that resistance to malaria may have developed as recently as 1600 years ago:
Tishkoff, S.A. et al. (2001) Haplotype Diversity and Linkage Disequilibrium at Human G6PD: Recent Origin of Alleles That Confer Malarial Resistance.
Science, 293, 455 - 462.
in addition to work which demonstrates that a gene important in regulating brain size arose only 5800 years ago and was subject to very strong positive selection:
Mekel-Bobrov, N. et al (2005) Ongoing Adaptive Evolution of ASPM, a Brain Size Determinant in Homo sapiens.
Science, 309, 1720 - 1722.
The apogee of the whole recent positive selection stuff was reached last year when
John Hawks published a paper arguing for accelerated human evolution during the late Pleistocene. He has an excellent summary of his research
here and the paper is:
Hawks, J. et al. (2007) Recent acceleration of human adaptive evolution.
PNAS, 104, 20753-20758.
The conclusion of the paper is important in the context of what Steve Jones is saying:
It is sometimes claimed that the pace of human evolution should have slowed as cultural adaptation supplanted genetic adaptation. The high empirical number of recent adaptive variants would seem sufficient to refute this claim [3, 6]. It is important to note that the peak ages of new selected variants in our data do not reflect the highest intensity of selection, but merely our ability to detect selection. Due to the recent acceleration, many more new adaptive mutations should exist than have yet been ascertained, occurring at a faster and faster rate during historic times. Adaptive alleles with frequencies under 22% should then greatly outnumber those at higher frequencies. To the extent that newadaptive alleles continued to reflect demographic growth, the Neolithic and later periods would have experienced a rate of adaptive evolution more than 100 times higher than characterized most of human evolution. Cultural changes have reduced mortality rates, but variance in reproduction has continued to fuel genetic change [47]. In our view, the rapid cultural evolution during the Late Pleistocene created vastly more opportunities for further genetic change, not fewer, as new avenues emerged for communication, social interactions, and creativity.
Now, it's important to note that the research above is generally looking at things that have occurred in the last few thousand years, so it's possible that Jones is right and that human evolution has stopped in the last 100 years or so. However it's a conclusion reached without any actual evidence. When we consider the large amount of evolution taking place up until very recently (and possibly continuing) and the final bolded sentence above, we should be very wary of what Jones says.
For a more specific look at why Jones is wrong, read
Razib over at Gene Expression. Key quote:
When I initially read the quotes from Jones in The Times I was alarmed, but wondered if his position was being taken out of context or misinterpreted. I emailed a prominent evolutionary biologist who I suspected would know Jones well enough to clarify this issue. My correspondent responded that Jones really does believe this, and he finds Jones' ideas as ludicrous as I do (adding for good measure he doesn't get the sense that Jones has a really good grasp of population genetics).
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