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Old 03-09-2006, 07:53 AM   #1
Ben Kaminski
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This article was forwarded to me and I thought it was very interesting.

http://news.yahoo.com/s/space/20060308/sc_space/hundredsofhumangenesstillevolvin g

The article describes a study which claims to have observed natural selection favoring various genes in the past 10,000 years. At this time I have not yet done any background research on the original study, but the results still look interesting as they suggest that significant evolution is possible and has taken place in the last 10,000 years.
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Old 03-10-2006, 03:00 PM   #2
Scott Kustes
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Here's the complete study for any that are interested.

http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journ al.pbio.0040072

Of course, this shouldn't come as a surprise for those of us believing in evolution. One of the tenets of evolution is that it doesn't stop. It may slow down or speed up at times, but never stops.
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Old 03-13-2006, 10:31 AM   #3
Neal Winkler
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Actually, it would be a suprise to many members of this community, as the paleo diet is based upon the proposition that humans have not changed since the advent of agriculture.
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Old 03-13-2006, 02:23 PM   #4
Ben Kaminski
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exactly.
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Old 03-13-2006, 02:58 PM   #5
Roger Harrell
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I wouldn't say that the human species is evolving. Our genetic pool may be diversifying, but there's no natural selection in any specific direction. We're creating possibly select lines by sexual (cultural) selection and some survival selection, but overal most everyone is able to survive and breed, hense, limited selective pressure.
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Old 03-13-2006, 04:24 PM   #6
Kevin McKay
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Roger,

That is my understanding as well. It seems like very few people if any would actually die before having a chance to procreate because of a genetic predisposition for poor Carbohydrate metabolism or Olfaction. Isn't it necessary for animals with a poor trait to die before breeding for natural selection/evolution to occur?
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Old 03-13-2006, 05:17 PM   #7
Roger Harrell
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If the health detriments only occur after optimal breeding time the selective pressure is dramatically blunted. Any factor that only has detrimental impact after 40 years old would have very limited impact on selection in humans. The detrimental effect does not have to cause death to have selective pressure though. A genetic defect that caused on to suddenly be covered in rotting flesh starting at the age of 12 would have powerful selective effects because the individual impacted would have a tough time reproducing, regardless of their survivability. They may live to 200 years old, never procreating. Hense genetic lines stopped. In many situations sexual selection is more powerful than survival selection.
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Old 03-13-2006, 05:23 PM   #8
Ross Hunt
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My understanding (with apologies to Darwin) is that natural selection only one of many mechanisms that cause evolution.

If memory serves, in a paper written in the first decade of the twentieth century, the Russian geneticist Chetverikov indicates that the effects of a selection get lost in the genetic soup after a couple generations. Chetverikov explains that natural selection is merely one means by which the true causes of evolution operate. He takes these causes to be mutation of genes and isolation of one part of the population from another.

I once wondered about how Scandanavians could have developed lactose tolerance. So I took Chetverikov's early 1900s numbers on the propagation of a dominant trait through a population, plugged in 15-20 years for a generation length, and--voila!--a dominant trait takes less than 3000-5000 years to spread, if I remember correctly.

The bottom line is: I get to eat my cottage cheese. :biggrin:
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Old 03-14-2006, 03:32 AM   #9
Jason Erickson
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There are several muscles in the body that are disappearing. Common a century ago, the plantaris muscle (located in the lower leg near the kneed) is often missing now. Contrary to popular belief, evolution does not always follow a gradual progression. Sometimes significant changes happen in a short span of time. It only takes a couple of generations to reinforce and spread the change.

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Old 03-14-2006, 11:05 AM   #10
Garrett Smith
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The changes that come with poor diet move to younger and younger ages through generations. Note "adult-onset" diabetes moving into pre-teens. Note the rampant infertility. Natural selection is moving along nicely.

I'm thinking that the selection will be in favor of those who choose to learn about proper nutrition and what it will do to them and future generations.

Remember, with Pottenger's cats, it only took 5 generations of the worst-diet cats to completely die off due to infertility and disease!
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