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External
Since: May 10, 2006
Posts: 49
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(Msg. 1) Posted: Mon Dec 17, 2007 9:28 pm
Post subject: Cochran And Harpending See Human Evolution Acceleration
Imported from groups: alt>non>racism, others (more info?)
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External
Since: Jun 29, 2004
Posts: 300
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(Msg. 2) Posted: Tue Dec 18, 2007 5:59 am
Post subject: Re: Cochran And Harpending See Human Evolution Acceleration [Login to view extended thread Info.]
Archived from groups: alt>non>racism, others (more info?)
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127.0.0.1 wrote:
>
> Another nail in the coffin of the flawed multiculturalism experiment.
>
> Cochran And Harpending See Human Evolution Acceleration
>
----------------------------
None of that has relation to either multicuturalism or "race".
And the flaw I see is that even if SNPs are variant, it does NOT
show that they are proceeding anywhere, just that mutations are
possible without being fatal, and that this is the natural source
of human variation WITHIN groups.
Should one trust a website called "futurepundit"??
I saw no documented data there, just surmise. That's NOT a "study".
Are these a few guys who have a political agenda?
These questions need answers!
Steve |
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Since: Dec 18, 2007
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(Msg. 3) Posted: Tue Dec 18, 2007 6:46 pm
Post subject: Re: Cochran And Harpending See Human Evolution Acceleration [Login to view extended thread Info.]
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Since: Feb 27, 2004
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(Msg. 4) Posted: Wed Dec 19, 2007 4:09 pm
Post subject: Re: Cochran And Harpending See Human Evolution Acceleration [Login to view extended thread Info.]
Archived from groups: alt>non>racism, others (more info?)
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"127.0.0.1" <127.0.0.1W.0.0.1>
> Another nail in the coffin of the flawed multiculturalism experiment.
It is? Why?
-- cary
>
> Cochran And Harpending See Human Evolution Acceleration
>
> Evolutionary theorist Greg Cochran and genetic anthropologist Henry Harpending have teamed up again and with John Hawks, Eric Wang, and Robert Moyzis to argue that human evolution has greatly accelerated in the last 10,000 years and the human race is dive
> rging.
>
> Dec. 10, 2007 - Researchers discovered genetic evidence that human evolution is speeding up - and has not halted or proceeded at a constant rate, as had been thought - indicating that humans on different continents are becoming increasingly different.
>
>
> "We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago," says research team leader Henry
> Harpending, a distinguished professor of anthropology at the University of Utah.
>
> Harpending says there are provocative implications from the study, published online Monday, Dec. 10 in the journal Proceedings of the National Academy of Sciences:
>
> * "We aren't the same as people even 1,000 or 2,000 years ago," he says, which may explain, for example, part of the difference between Viking invaders and their peaceful Swedish descendants. "The dogma has been these are cultural fluctuations, bu
> t almost any Temperament trait you look at is under strong genetic influence."
>
> * "Human races are evolving away from each other," Harpending says. "Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin. We are getting less alike, not merging into a single, mixed h
> umanity." He says that is happening because humans dispersed from Africa to other regions 40,000 years ago, "and there has not been much flow of genes between the regions since then."
>
> "Our study denies the widely held assumption or belief that modern humans [those who widely adopted advanced tools and art] appeared 40,000 years ago, have not changed since and that we are all pretty much the same. We show that humans are changing re
> latively rapidly on a scale of centuries to millennia, and that these changes are different in different continental groups."
>
> The increase in human population from millions to billions in the last 10,000 years accelerated the rate of evolution because "we were in new environments to which we needed to adapt," Harpending adds. "And with a larger population, more mutations occ
> urred."
>
> Study co-author Gregory M. Cochran says: "History looks more and more like a science fiction novel in which mutants repeatedly arose and displaced normal humans - sometimes quietly, by surviving starvation and disease better, sometimes as a conquering
> horde. And we are those mutants."
>
> Harpending conducted the study with Cochran, a New Mexico physicist, self-taught evolutionary biologist and adjunct professor of anthropology at the University of Utah; anthropologist John Hawks, a former Utah postdoctoral researcher now at the Univer
> sity of Wisconsin, Madison; geneticist Eric Wang of Affymetrix, Inc. in Santa Clara, Calif.; and biochemist Robert Moyzis of the University of California, Irvine.
>
> Using data from the International Haplotype Map Project on single nucleotide polymorphisms (SNPs which are single letter genetic differences)
>
> Harpending and colleagues used a computer to scan the data for chromosome segments that had identical SNP patterns and thus had not broken and recombined, meaning they evolved recently. They also calculated how recently the genes evolved. A key findin
> g: 7 percent of human genes are undergoing rapid, recent evolution.
>
> So we are becoming less alike due to adaptations to local environments. My guess is this trend will accelerate when offspring genetic engineering becomes possible. People in different cultures, religions, climates, occupations, social classes, and regulat
> ory environments will make different decisions on which genetic variations to give their offspring. As a result groups will become less alike. Some groups will choose genes that enhance analytical ability and mathematical skills. Some will emphasize genes
> that boost ambition and perhaps even ruthlessness. Others will go for genetic variations that increase moral motivation and spirituality.
>
> Update: The divergence of human genomes is a result of growing human populations moving into lots of different habitats that each exert different selective pressures. The selective pressures operated on immune systems, musculature, hair, skin, brains, and
> many other aspects of human shape and physiology.
>
> It says something about the adaptive value of specific temperaments to specific habitats that these researchers report big selective pressures on genes that control temperament. That makes sense if you think about it intuitively. A hunter probably needs a
> different temperament than a goat herder (who experiences a lot of solitude) who needs a different temperament than a merchant (who interacts with many other humans and needs to enjoy sizing them up quickly). Some tasks are far more cognitively demanding
> than others. Some tasks require much more hand-eye coordination or better balance or more strength or endurance. Humans working at different tasks to survive in different environments got selected to be shorter or taller, better sprinters or better long
> distance runners, more muscular or fatty or skinny, and many other attributes. This is akin to specialization of labor.
>
> See the John Hawks introduction to the paper on his blog. Also see his "Acceleration rarely asked questions" about the research. Hawks says the selective pressures acting on human genomes have been so strong in recent history that the signal they are meas
> uring is larger than the biases one might expect would make the data hard to interpret.
>
> In the earliest studies, when people were finding that 3 or 4 percent of a sample of genes had signs of recent selection, those numbers were already extremely high. They got even higher, as more and more powerful methods of detecting selection came on
> line. Our current estimate is the highest yet, but even this very high number is perfectly consistent with theoretical predictions coming from human population numbers.
>
> At one level, the mathematical answer is as simple as "more people means more mutations." But more deeply, we can predict a linear response of new selected alleles to population size, and we can model this response with respect to a particular frequen
> cy range. The genome is a complicated place -- with different mutations originating at different times, selected at different strengths, consequently with different fixation probabilities and different current frequencies. For some reason, nobody really t
> ried to describe this mathematically before.
>
> Now, our model is extremely simple -- it can be challenged on several specific bases. For instance, population increase was not a simple exponential -- it grew in fits and starts, with some significant crashes. The average strength of selected mutatio
> ns probably changed over time, and the distribution of the strength of selection may have departed from our assumptions. Even the adaptive mutation rate may have changed over time.
>
> Still, the general prediction is quite clear: the population has grown, its conditions of existence have changed, and as a result selection on new mutations should have accelerated. And the observed data fit our theoretical prediction exceptionally we
> ll. Certainly we could do better if we made a more detailed model, and we will be doing some of that in future papers. But mathematical simplicity has a great virtue: we can see precisely why human historical changes should have accelerated this aspect of
> our evolution, and we can see the magnitude of the response. That magnitude greatly outweighs all potential biases.
>
> Go read the full Hawks post. It is all worth reading.
> http://www.futurepundit.com/archives/004848.html >> Stay informed about: Cochran And Harpending See Human Evolution Acceleration |
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