Selection Spurred Recent Evolution, Researchers Say
 
By NICHOLAS WADE
Published: December 11, 2007

Researchers analyzing variation in the human genome have concluded that human evolution accelerated enormously in the last 40,000 years under the force of natural selection.

The finding contradicts a widely held assumption that human evolution came to a halt 10,000 years ago or even 50,000 years ago. Some evolutionary psychologists, for example, assume that the mind has not evolved since the Ice Age ended 10,000 years ago.

But other experts expressed reservations about the new report, saying it is interesting but more work needs to be done.

The new survey — led by Robert K. Moyzis of the University of California, Irvine, and Henry C. Harpending of the University of Utah — developed a method of spotting human genes that have become more common through being favored by natural selection. They say that some 7 percent of human genes bear the signature of natural selection.

By dating the time that each of the genes came under selection, they have found that the rate of human evolution was fairly steady until about 50,000 years ago and then accelerated up until 10,000 years ago, they report in the current issue of The Proceedings of the National Academy of Sciences. The high rate of selection has probably continued to the present day, Dr. Moyzis said, but current data are not adequate to pick up recent selection.

The brisk rate of human selection occurred for two reasons, Dr. Moyzis’ team says. One was that the population started to grow, first in Africa and then in the rest of the world after the first modern humans left Africa. The larger size of the population meant that there were more mutations for natural selection to work on. The second reason for the accelerated evolution was that the expanding human populations in Africa and Eurasia were encountering climates and diseases to which they had to adapt genetically. The extra mutations in their growing populations allowed them to do so.

Dr. Moyzis said it was widely assumed that once people developed culture, they protected themselves from the environment and from the forces of natural selection. But people also had to adapt to the environments that their culture created, and the new analysis shows that evolution continued even faster than before.

The researchers took their data from the HapMap project, a survey designed by the National Institutes of Health to look at sites of common variation in the human genome and to help identify the genes responsible for common diseases. The HapMap data, generated by analyzing the genomes of people from Africa, East Asia and Europe, has also been a trove for people studying human evolutionary history.

David Reich, a population geneticist at the Harvard Medical School, said the new report was “a very interesting and exciting hypothesis” but that the authors had not ruled out other explanations of the data. The power of their test for selected genes falls off in looking both at more ancient and more recent events, he said, so the overall picture might not be correct.

Similar reservations were expressed by Jonathan Pritchard, a population geneticist at the University of Chicago.

“My feeling is that they haven’t been cautious enough,” he said. “This paper will probably stimulate others to study this question.”


http://www.nytimes.com/2007/12/11/science/11gene.html?ref=science

I found these:
http://www.pnas.org/cgi/search?fulltext=Robert+K.+Moyzis+&submit.x=8&submit.y=11

Are you talking about the specific research? I just assumed you would need a subscription to view it. Hold on.


edit: Here:
http://www.pnas.org/cgi/content/full/99/1/309?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=Harpending+Moyzis&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT

The articles seem to confirm that modest alterations in non critical and begnine areas of protein structures proceed roughly in proportion to those predicted by mutation rates, and genetic drift.  Still billions and billions of times too slow to account for observed diversity when we look at the critical alterations required to define new functional proteins with different spacial and binding site configurations.  The article conveniently leaves this fact out.  The articles confirm what we already know about the limited capability of evolutionary processes but does nothing to show how evolution might account for the kind of changes required to change an ape into a human.

An article that discusses this predicament fairly well is by Gavrilets, in 2004 "Fitness landscapes and the origin of species", published by Priceton University Press.

At what rate does observed evolutionary processes create new protein function require to define a new species and new structures?  Experimental evidence answers this quesion and the answer is that it doesn't get far and  Theoretical Biology shows us why.  This article provides an explanation for why that is.  Orr shows that mutation of a single gene is likely to take on average two steps along a prospective pathway before getting stuck, unable to proceed because the next steps are detrimental.

Orr, H. A., 2003, A minimum on the mean number of steps taken in adaptive walks, Journal of Theoretical Biology 220
 
  The evidence suggests the rate is billions of billions times too slow.  These studies you have provided are simply confusing the two issues.

Orr's article describes several situations and makes several points on this topic.  Rosenberg's refinement makes my point stronger since he claims the minimum average is even faster that Orr's claim thus indicating that evolutionary processes are theoretically likely to get stuck sooner in a prospective pathway.

Aw, that's a low blow and unfair and you know it!  How dare you confuse the issue with the multiple lines of evidence!  You are supposed to ignore anything that doesn't have to do with his Argument from Improbability. Can't you see he's trying to create a reason not to believe science?

That may be disturbing news to the cladists.


One time or another? I believe the timing is fairly specific. I imagine if you had credible problems with the dating of the geologic column you would have brought that up by now.


So if these fossils represent different "kinds" at different times you have no objection to the concept of change through time? Can common descent be far behind?


So is everyone else. That's why they do the work. I'm pretty sure it would be evident by now if modern biology was totally on the wrong track. But if you have a viable alternative to descent with modification, let's hear it.

Came across this. Maybe the scientists on the board will find it interesting.

http://endogenousretrovirus.blogspot.com/2007/08/michael-behe-please-allow-me-to.html

Rf, this is why I worry about you.  The fossil record doesn't JUST tell us that "an organism had a particular configuration".  This is so blatantly a lie or misrepresentation that I wonder if you even care what you say.

The fossil record tells us that organisms gained in size and complexity over time, are millions of years old and had certain configurations at certain times and not others.

For you to ignore the implications shows that you are trying to be ignorant.