March 28, 2007
Cochran And Hawks Detect Human Evolution Acceleration

Evolutionary theorist Gregory Cochran and anthropologist John Hawks claim to have found evidence of a huge increase in the rate of human evolution in the more recent period of human evolution of the last 40,000 years.

Hu­man ev­o­lu­tion has been speed­ing up tre­mend­ous­ly, a new study con­tends—so much, that the lat­est ev­o­lu­tion­ary changes seem to large­ly ec­lipse ear­l­ier ones that ac­com­pa­nied mod­ern man’s “ori­gin.”

Contrary to the common view that humans have changed little since out-of-Africa Cochran and Hawks think big changes have come since humans emerged as a distinct species.

“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.

Cochran and Hawks see a 2 orders of magnitude acceleration in human evolution in the last 40,000 years.

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 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 ex­tinct, more ape-like though up­right-walk­ing an­ces­tors and rel­a­tives.

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.

Humans were already spread over large areas of land 40,000 years ago and were evolving to better fit their local environments. If human evolution has been rapid then different population groups likely possess important unique adaptations to local circumstances and the differences between groups are larger than politically correct people would like us to believe.

This reminds me of a recent paper in Nature Genetics that found a quarter of genes show different expression levels in Europeans and East Asians.

Ethnicity stems not just from differences in genetic sequence, but also from differences in the expression of genes shared by ethnic groups, according to a new study in Nature Genetics. The authors found that 25 percent of genes show different expression levels in Asian and European individuals, and single-nucleotide polymorphisms (SNPs) in regulatory elements likely account for many of these variations.


To see if some of these polymorphisms could cause differences in gene expression levels, researchers led by Richard Spielman of the University of Pennsylvania in Philadelphia assayed gene expression differences between ethnic groups.

Spielman and his colleagues measured expression levels of more than 4,000 genes in lymphoblastoid cell lines derived from individuals from three different populations: Chinese, Japanese, and European. They found that gene expression levels from the Chinese and Japanese groups were largely the same, but that expression levels between the Asian groups and the European group differed significantly for more than 1,000 genes.

Local selective pressures produced so many differences.

Also see the March 2006 Plos Biology paper A Map of Recent Positive Selection in the Human Genome by Jonathan K. Pritchard and colleagues at the University of Chicago.

Cheaper DNA testing technologies are going to produce a huge flood of reports on human evolution and human differences.

March 2009 Update: This work has since become the basis for an excellent book by Cochran and Harpending entitled The 10,000 Year Explosion: How Civilization Accelerated Human Evolution.

Share |      Randall Parker, 2007 March 28 07:50 PM  Trends, Human Evolution

John S Bolton said at March 28, 2007 11:57 PM:

This makes sense relative to the major selection events, involving the amerind and aboriginals, etc., are relatively recent in evolutionary time, and nothing like those could have occurred except in the more recent centuries.

James Bowery said at March 29, 2007 1:08 AM:

So what do you make of this Paracas skull?

Just another head-binding?

Kurt9 said at March 29, 2007 11:31 AM:

Its the cone-heads!

One of Steve Martin's long-lost ancestors.

Foger said at March 29, 2007 11:35 AM:

Well, this has been known for a long time. Anyone who studies evolution will notice that increasinglymore intelligence species have evolved in exponentially shorter times.

I found another article on accelerating change, across multiple areas. Fascinating stuff.

Joseph Hill said at March 29, 2007 11:48 AM:

Does this change hold true for lawyers and law teachers, anarchists, libertarians, athletes, school bus crossing guards, and dental hygiene assistants? Or just regular folks?

Steevo said at March 29, 2007 12:11 PM:

I've really noticed it in this past couple of generations, natural selection that is. The MO is greatly unhindered: If it doesn't satisfy me to hell with it; well you know.

John from OK said at March 29, 2007 1:01 PM:

Check your high school yearbook. Chicks are a lot hotter than they used to be. Random mutation or natural selection?

submandave said at March 29, 2007 1:01 PM:

Without really researching, I'd hazard to guess the linked skull gained that shape through disease. It basically looks like a normal skull with additional calcified growths. Ever get a look at John Merrick's bones?

M. Simon said at March 29, 2007 1:07 PM:

You might find Inequality of interest.

I look at athletic ability and IQ.

triticale said at March 29, 2007 3:12 PM:

Check your high school yearbook. Chicks are a lot hotter than they used to be. Random mutation or natural selection?

Better makeup, hairstyle and eyeglass frames, and lowered clothing standards.

Jeff said at March 29, 2007 5:31 PM:

Perhaps some of the evolution is due to diseases which require large concentrations of people to be viable. Think of how many people were killed by the Black Plague for example or the peoples of the Americas when they were exposed to European diseases.

comatus said at March 30, 2007 6:05 PM:

If no one has blamed global warming yet, please name this theory after me.

rsilvetz said at March 30, 2007 10:31 PM:

Yes, overall rings true to me. I also think it quite cool that the evolution is accelerating.

Having said that, in regard to group differences, we should also remember that the statistical differences between DNA are important in terms of biodiversity by not in terms of humanity. Last I looked the ethnic groups interbreed just fine. We remain and are one species. In other words, I am more similar to my ethnic group but not terribly different from other ethnic groups. Just because I can resolve folks into statistical groups that mirror ethnic groups does not, in of itself, mean I have penetrated an essential difference. I merely have acheived statistical resolution of the fact that branches of humanity have evolved in geographic seperation. We should not exagerrate the differences because we now have a statistical microscope.

These DNA differences in the long run have application in terms of individualized medicine and targeted therapy.

But as the poster on inequality mentioned, the politically correct have merely over-generalized the Founding Father's comment on equality of the law.

Bob Jenkins said at April 2, 2007 11:14 AM:

Assuming a constant rate of change of 1 mutation per conception, how is this surprising? If you have 100x the number of people, you have 100x the number of conceptions, so you have 100x the number of beneficial mutations.

I put up a page awhile ago,, where I tried to integrate the world population over time to find the distribution of genetic diversity in the human race. There were 100x more people in 1AD than in 1 million BC, and 60x more now than in 1AD. Over half the human diversity (that wasn't already with us at 1 million BC) appeared after 1750AD. So those beneficial mutations are mostly confined to tens to thousands of people each, often confined to one village somewhere, with about the same overall distribution as the human population.

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