Human evolution radically reappraised

The findings reported below are very politically incorrect stuff. They tend to show that the races of mankind are more different than was thought. Cochran, Lahn and others involved have previously got into big trouble from the Left over it. See here. One of the "more recent evolutionary changes" mentioned below was the comparatively recent emergence of new genes connected with brain size -- genes that seem to give a large intellectual advantage but which are mostly missing among Africans. See here and here for the academic journal abstracts. For the evidence linking brain-size and IQ, see section 6 here. I must say that I see pin-headed East-African refugees in the streets every day where I live. How incorrect of me to report that!

Human evolution has been speeding up exorbitantly, a new study contends; so much, that the latest evolutionary changes seem to largely eclipse earlier ones that accompanied modern man's "origin." The study, alongside other recent research on which it builds, amounts to a sweeping reappraisal of traditional accounts of human evolution. These generally assumed that humans have reached a pinnacle of evolution and stopped there. The findings suggest that not only is our evolution continuing: in a sense our very "origin" can be seen as ongoing, a geneticist not involved in the work said.

Gregory Cochran of the University of Utah in Salt Lake City, Utah, a co-author of the latest study, said the research may force a radical rethinking of the story of modern human evolution. "It turns it upside-down, pretty much," he said. The traditional view of humans as a finished product began to erode in recent years, scientists said, with a crop of studies suggesting our evolution indeed goes on. But the newest study goes further. It claims the process has actually accelerated.

It also downplays the importance of a much-scrutinized era around 200,000 years ago, when humans considered "anatomically modern" first appear in the fossil record. In the study, this epoch emerges as just part of a vast arc of accelerating change. "The origin of modern humans was a minor event compared to more recent evolutionary changes," wrote the authors of the research, in a presentation slated for Friday in Philadelphia at the annual meeting of the American Association of Physical Anthropologists. The authors are Cochran and anthropologist John Hawks of the University of Wisconsin-Madison. The findings will also be submitted to one or more scientific journals, Cochran said.

The proposal is "truly fascinating," wrote University of Chicago geneticist Bruce Lahn in an email. He wasn't involved in the work, though he did conduct earlier research finding that evolution may still be ongoing in the brain...

Hawks and Cochran analyzed measurements of skulls from Europe, Jordan, Nubia, South Africa, and China in the past 10,000 years, a period known as the Holocene era. They also studied European and West Asian skulls from the end of the Pleistocene era, which lasted from two million years ago until the Holocene. "A constellation of features" changed across the board, Hawks and Cochran wrote in their conference presentation. "Holocene changes were similar in pattern and... faster than those at the archaic/modern transition," the time when so-called modern humans appeared. But these changes "themselves were rapid compared to earlier hominid evolution." Hominids are a family of primates that includes humans and their upright-walking, more apelike ancestors and relatives, all extinct.

Hawks and Cochran also analyzed past genetic studies to estimate the rate of production of genes that undergo positive selection -- that is, genes that spread because they are beneficial. "The rate of generation of positively selected genes has increased as much as a hundredfold during the past 40,000 years," they wrote.

Among the most notable physical changes have been ones affecting the size of the brain case, according to Hawks and Cochran. A "thing that should probably worry people is that brains have been getting smaller for 20,000 to 30,000 years," said Cochran. But growth in more advanced brain areas might have compensated for this, he added. He speculated that an almost breakneck evolution of higher foreheads in some peoples may reflect this. A study in the Jan. 14 British Dental Journal found such a trend visible in England in just the past millennium, he noted, a mere eyeblink in evolutionary time. Research published in the Sept. 9, 2005 issue of the research journal Science by Lahn and colleagues found that two genes linked to brain size are rapidly evolving in humans.

Anthropologist Jeffrey McKee of Ohio State University said the Hawks and Cochran study bears out predictions he made in a 2000 book The Riddled Chain. Based on computer models, he argued that evolution should speed up as a population grows. This is because population growth creates more opportunities for new mutations; also, the expanded population occupies new environmental niches, which would drive evolution in new directions.....

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