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Old 03-08-2006, 07:25 AM   #1
Tenspace
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Here's an excellent paper providing some of the first results from the HapMap project:

In this study, we use newly available, dense, single nucleotide polymorphism (SNP) data from the International HapMap Project [18] to create a first-generation map of selection across the human genome. Our search is aimed at finding loci where there is strong, very recent, selection in favor of alleles that have not yet reached fixation. By doing so, we aim to provide preliminary answers to these questions about the nature and extent of recent adaptation in modern humans. The loci that we identify will start to fill in the details about the ways in which modern humans have adapted to the selective pressures in the most recent stage of our evolution.

Documented evolution in action. Yes, we are definitely still evolving, according to this report.

Salty, what do you think? Should these scientists just quit their jobs and become bean farmers?

Here's the link: A Map of Recent Positive Selection in the Human Genome

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Old 03-08-2006, 07:44 AM   #2
Philboid Studge
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Quote:
Tenspace wrote
Salty, what do you think? Should these scientists just quit their jobs and become bean farmers?
Yeah, magic bean farmers, so they'll have something to sell to the rubes.

This is only slightly OT (I consider all threads on evolution to be wide open), but what do y'awl think of the concept of 'reverse evolution'? (I don't like the phrasing, because it suggests evolution has a 'forward'.) It's the theory that genetic faults can cause a kind of regression (think William Hurt in 'Altered States').

This Times of London piece doesn't explain a whit of the science, but one of the eggheads they interview (an evolutionary psychologist at the London School of Economics -- I had no idea there was such a thing) said these people 'appeared to have reverted to an instinctive form of behaviour encoded deep in the brain, but abandoned in the course of evolution.'

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Old 03-08-2006, 07:52 AM   #3
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Quote:
Tenspace wrote
Salty, what do you think?
Heh heh. He said "think", heh heh heh.

edit:

Pharyngula has a good description of his technique for teaching about the genome's role in developmental biology.

Of course, Salty is a living, breathing Gary Larson cartoon so what PZ Myers writes is:

Quote:
Pharyngula wrote
Think of the genome as analogous to the power spectrum; we'll call it the genomic spectrum. The organism is like the reconstructed image; we'll call that the phenotypic image. A mutation is like the filters applied to the power spectrum. Most discrete mutations will have small effects, and they will be expressed in every cell, while some mutations will affect prominent aspects of the phenotype and will be readily visible. Genes don't directly map to parts of the morphology, but to some abstract component that will contribute to many parts of the form to varying degrees. There is no gene for the tip of your nose, just as there is no speckle in the power spectrum responsible one of the folds in the membrane of the epithelial cell image.

And what is development? It isn't represented in any of the pictures. Development is the Fourier transform itself, or the lens of the microscope; it's the complex operation that turns an abstraction into a manifest form. What results is dependent on the pattern in the genome, but it's also dependent on the process that extracts it.
And what Salty reads is:

Quote:
Idiot believes that life came from a rock wrote
Blah blah blah blah blah blah blah blah genome blah blah blah we didn't come from fossils blah blah blah blah something can't come from nothing blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah evolution is religion blah blah blah blah blah blah blah can't observe macroevolution therefore it's false blah blah blah blah blah blah blah blah blah blah blah blah blah blah. Blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah...
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Old 03-08-2006, 08:06 AM   #4
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The question for me has never been whether or not we (humans) were evolving 10,000 years ago, or even if evolution is still taking place today, on planet earth. The question for me has been are we (countries like america where we take care of our poor and sick) still evolving, evolving at a reduced rate, or basically not evolving because we have just about stopped the process of natural selection? My guess is we're creating greater and greater variance among our genes, but our selection process has been greatly reduced. Now I didn't read the entire article, (it's long and technical) but it looks like they are presenting evidence that evolution was taking place around 10,000 years ago. I think it's quite a jump to go from that to "we're definitely still evolving". Maybe I missed something though.
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Old 03-08-2006, 08:24 AM   #5
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StillSurviving wrote
Maybe I missed something though.
Try this NYT reviewof the study.
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Old 03-08-2006, 08:32 AM   #6
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We can't stop evolution. Natural selection occurs no matter if we take care of our sick or not the environment changes and what is advantageous and what isn't does, but evolution will still occur. On another thread someone pointed out the Hardy-Weinberg equation which is a good comparison to see if your hypothesis is correct:

Quote:
Hardy, Weinberg, and the population geneticists who followed them came to understand that evolution will not occur in a population if seven conditions are met:

1. mutation is not occurring
2. natural selection is not occurring
3. the population is infinitely large
4. all members of the population breed
5. all mating is totally random
6. everyone produces the same number of offspring
7. there is no migration in or out of the population
Source http://anthro.palomar.edu/synthetic/synth_2.htm
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Old 03-08-2006, 09:49 AM   #7
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Quote:
Philboid Studge wrote
What do y'awl think of the concept of 'reverse evolution'? (I don't like the phrasing, because it suggests evolution has a 'forward'.)
From what I've read, the nylonase enzyme is actually "less efficient than the precursor protein it's believed to have developed from," implying the kind of "reverse evolution" I think you're pointing out.
http://www.livescience.com/othernews...D_science.html

I agree that evolution has no "forward" or "reverse" modes. The common misconception is that the process of evolution results in qualitatively better or higher forms of life, when it is actually nothing more than a lateral move of adaptation. Humans, baboons and aardvarks are all equally evolved, because they are suited to the environments that they occupy.

That's why I view the whole concept of exctinction with a degree of suspicion. When we say that dinosaurs went exctinct, we mean that the animal does not exist today as it did then. But the more likely scenario is that the process of evolution slowly changed certain dinosaur species into various reptilian and avian species. Over millions of years, all dinosaur species were changed into the species that we have today; the fossils that we have are merely the transitional individuals.

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Old 03-08-2006, 11:04 AM   #8
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Interestig quotes from the NY times article:
================
Dr. Pritchard's scan of the human genome differs from the previous two because he has developed a statistical test to identify just genes that have started to spread through populations in recent millennia and have not yet become universal, as many advantageous genes eventually do.

The relative handful of selected genes that Dr. Pritchard's study has pinpointed may hold the answer, he said, adding, "Each gene has a story of some pressure we adapted to."
================

In order for a gene to become universal because of the advantage it offers, there must be some pressure that is keeping those without the gene from passing on the old gene. Outside of locking up criminals, I don't see much going on in developed countries that would constitute that pressure. Those who can't take care of themselves are being cared for by others. There are diseases we can't cure, so there would be some pressure for people most susceptible to those to die out. Perhaps there's a breading gene that tells some people to have 12 kids, each of which will want to have 12 kids. Eventually through probability, it may be that those who only want 2 kids are unlikely to find each other, and thus end up with someone who wants 12 kids, and have 12 kids that want 12 kids. I don't think we'll adapt for technology the way we adapted for agriculture. Being a good farmer 6,000 years ago meant you had more food to feed your kids, making them stronger, less sickly, and more likely to survive to have kids of their own. Now, the same could be said for very technologically savy people who land great, high paying jobs and could afford to feed hundreds of their own kids, but they aren't having any more kids than anyone else. Actually, it seems that those best adapted for their environment today (as far as having things go the way they want them to) are having fewer children than those who are less able to mold the world around them into what they want.
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Old 03-08-2006, 01:18 PM   #9
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Quote:
StillSurviving wrote
The question for me has never been whether or not we (humans) were evolving 10,000 years ago, or even if evolution is still taking place today, on planet earth. The question for me has been are we (countries like america where we take care of our poor and sick) still evolving, evolving at a reduced rate, or basically not evolving because we have just about stopped the process of natural selection? My guess is we're creating greater and greater variance among our genes, but our selection process has been greatly reduced. Now I didn't read the entire article, (it's long and technical) but it looks like they are presenting evidence that evolution was taking place around 10,000 years ago. I think it's quite a jump to go from that to "we're definitely still evolving". Maybe I missed something though.
Evolution has always been about populations. Our target population is no longer America, or the Congo, or the Galapagos, but the entire planet, thanks to communication and transportation.

"Science and Mother Nature are in a marriage where Science is always surprised to come home and find Mother Nature blowing the neighbor." - Justin's Dad
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Old 03-08-2006, 01:31 PM   #10
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Quote:
StillSurviving wrote
In order for a gene to become universal because of the advantage it offers, there must be some pressure that is keeping those without the gene from passing on the old gene. Outside of locking up criminals, I don't see much going on in developed countries that would constitute that pressure
.

Sexual selection is rampant - do you see a difference between the peacock's tail and a dude in an Armani suit? ;)

Selection pressures, especially in the case of this report, are coming from not only environmental and cultural factors (which themselves can be guided by genes), but from biophysical factors, such as variation in immune systems.

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Old 03-08-2006, 02:11 PM   #11
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I see the guy with no Armani suit getting four different similarly hard up girls pregnant, while the guy with the Armani suit only has 1-2 kids. Then those girls turn around and get pregnant again by a different guy with no suit.
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Old 03-09-2006, 08:19 AM   #12
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And that's the exact point of sexual selection. The guy with the Armani suit is (in our culture, anyway) a better-qualified mate than the guy in the wifebeater and Wranglers. Although the Bubba may have more kids, the Armani suit will have kids better selected for survival. If Bubba can't diversify, explore, mingle with other populations and the like, he's on a straight track to a whole chemistry set of lethal mutations for future offspring.

Why do you think the last words out of the mouths of most rednecks run along the lines of, "Hey y'all, watch this!" :)

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Old 03-09-2006, 11:01 AM   #13
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I just don't see it like that Tenspace. I see bubba increasing his numbers, and Armani decreasing his.
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Old 03-09-2006, 11:26 AM   #14
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The way I see it, bubba is too dumb to keep a lighter away from his many kids when they're too young and dumb to understand the danger of it. One of bubba's kids burns himself to death. Bubba sues the lighter manufacturer and wins. The lighter manufacturer pays engineers to develop a lighter that will keep bubba's other kids from burning themselves to death. The engineer is not only protecting his own kid, but bubba's kids too. Plus the money the engineer pays in taxes are used to pay to provide food stamps and medicare for other bubbas and their kids. (Since the original bubba now has plenty of money from the settlement.)
It saddens me some to see the population skewing this way.
It might sadden me more to see millions of bubbas and their kids starving to death or dying in accidents though. I'm not saying the world should be different, just trying to describe what I see happening.
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Old 03-09-2006, 11:46 AM   #15
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Quote:
StillSurviving wrote
It saddens me some to see the population skewing this way.
It might sadden me more to see millions of bubbas and their kids starving to death or dying in accidents though. I'm not saying the world should be different, just trying to describe what I see happening.
Your "Generation of Bubbi" is really a problem which solves itself, as you hint in the last part of your reply. If enough Bubbi manage to propogate in that manner, society, and the system of social supports upon which the Bubbi are depending, collapses and the Bubba population experiences an inevitable contraction. Another possibility is that the laws which allow the Bubbi to poach from others will eventually be changed.

Statistically, by elevating a specific segment of the Bubba population into a more prosperous socio-economic strata, a portion of them will escape their ancestry while those who cannot adapt will squander their resources and slip back into mainstream Bubbaism.

edit: to remove egregious condescension
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