Gene SLC24A5 and selection....

First of all, I want to state that I'm not completely against the evolutionism, I think that the natural selection decided somehow big "lines" of the life evolution.
But... some days ago, I read on the newspaper that a defect in our gene SLC24A5 has determined our adaptation in the different part of the world.
live.psu.edu...
ok, it sounds good to me: this gene decide about the pigmentation of the skin. The humans who presented this defect produced more vitamin D in the region of the world where there is less light, but.... some says that, base on the evolutionism, only the population who presented this defect, could survive in region where there less sun. And so, this is why there were no black people, anymore in region like europe, ural, ... What? This is to say that only a few of the travelers survived far from Africa??? Or that the women didn't make baby with the men who where not "affected"?
In this case, I would like to advise the thousands imigrants coming in our countries that they are in danger of instinction!!!
Yes, go back into your countries, you'll live better there... doesn't it sound racism to you??

In my opinion, it is more probable that the human gene "adapt" to the local condition... through unveiled "decisional" behavior or system. What do you think about it?

ps: I hope I've been clear . Sorry if I mispelled some important words for the meaning...

I think you misunderstand the fundamental basis of evolution theory completely, and no, it doesnt sound racist to me.

Evolution dictates that those better fit to survive are more likely to do so, and given a prolonged period of time, that trait is therefore more likely to be genetically passed on. If you need me to explain why this occurs in detail, just let me know.

What this means is that a certain genetic trait could make it difficult for a species to survive in certain conditions over the long run. However, with todays medicine and advanced genetic and scientific knowledge, a gentic trait that dictates skin pigmentaion and vitamin d production is meaningless. This is due to the enviroment we create as humans for other humans. Our knowledge makes it a non-issue. Again, if you would like further explanation, just let me know.

The key to all of this is long term environmental conditions. Not short term. Reading this article only provides me with additional information in support of evolution theory. It in no way is "racist". I have no idea where you came up with that.

Just as a side note. Adapt in the way you are referring to it is along the lines of mutation. Mutations most certainly do occur, and are a part of the evolutionary process. However, they are just that, a part.



[edit on 20-12-2005 by Sight2reality]

Originally posted by Sight2reality
I think you misunderstand the fundamental basis of evolution theory completely.

Don't worry, I know exactly what Darwin stated... and I repeat: I'm not telling that this is wrong! I was a bit sarcastic in my post

But this is more likely explaining very long run or sudden changes... I'm not sure that this apply for the human relatively short evolution. Humanity is not made of extremly strong or intelligent persons... it's very balanced. And this is not recent, it's not even one or two thousand old...

Another example: the maya food, based on mais, was lacking of some nutriments, so they found some alkali processing to im- prove the balance of amino acids and the yield of nutrients. Is it the proof that we were a long long time ago already able to face desastrous situations?

Originally posted by Sight2realityIt in no way is "racist". I have no idea where you came up with that.

Well ok, I extrapolated

[edit on 20/12/2005 by Lillo]

Originally posted by Lillo
this gene decide about the pigmentation of the skin. The humans who presented this defect produced more vitamin D in the region of the world where there is less light

Okay, let's see if there aren't some issues we can't clear up.

You are in fact correct, the evidence suggests that the gene in question is in fact involved with skin pigmentation. This is the fact of the research. The hypothesis about skin pigmentation, vitamin D, and European migration are not facts in the same sense. They are speculation based on facts.

but.... some says that, base on the evolutionism, only the population who presented this defect, could survive in region where there less sun. And so, this is why there were no black people, anymore in region like europe, ural, ... What? This is to say that only a few of the travelers survived far from Africa??? Or that the women didn't make baby with the men who where not "affected"?

As the other poster mentioned, evolutionary theory doesn't speak to absolutes, only to probabilities. A certain mutation may increase the probability that an organism will survive long enough to reproduce under a particular set of selective conditions. There are in fact very few absolutes in Biology.

In my opinion, it is more probable that the human gene "adapt" to the local condition... through unveiled "decisional" behavior or system. What do you think about it?

I think what you are saying is that is the genes somehow respond to environmental influence and adapt (mutate) as a function of particular selective conditions.

Sort of opens up a big can of worms for me, but I'll try to be brief.

This isn't generally how Darwinian Theory is thought to operate, it's generally thought to operate via selective pressure on random variations that result from processes such as genetic recombination, and random mutation.

However, this is not to say there isn't a precedent for what appears to be adaptive behavior in populations of microorganisms. Some bacteria - under certain selective (stressful) conditions engage in hypermutation of specific regions of chromosal or extrachromosomal DNA. Though, bacteria can afford to do this due their rapid rate of reproduction and single-celled lifestyle.

Thus far, it doesn't appear that multicellular organisms that contain a wide variety of differentiated tissues and interacting parts, are capable of such a feat. For all the cells of your body to engage in hypermutation would likely not be good.

Though there is a precedent for this. The human immune system can produce likely an infinite number of antibodies; and this accomplished via hypermutation of very specific regions of the genome by very specific cell types. The process - thus far anyway appears to be very limited in multi-cellular eukaryotes, but is becoming more widely recognized as occuring in prokaryotes.

BTW, I think what you are referring to with respect to the Mayans is Niacin deficiency. There's lots of niacin present in corn, but is not bio-available unless you prepare the corn via cooking in 'lime water.' I am not sure exactly how you were trying to correlate this with the other stuff, but I am actually intrigued by such things myself. How did they know how to do that? It's sort of interesting, but nothing I've ever really studied in depth.



[edit on 20-12-2005 by mattison0922]

Thanks for your comments mattison, they were constructive and very interesting!

Originally posted by mattison0922
As the other poster mentioned, evolutionary theory doesn't speak to absolutes, only to probabilities. A certain mutation may increase the probability that an organism will survive long enough to reproduce under a particular set of selective conditions. There are in fact very few absolutes in Biology.
....
I think what you are saying is that is the genes somehow respond to environmental influence and adapt (mutate) as a function of particular selective conditions.

About mutation, I remember that there are some species (some kind of lezard. Anyone knows the name?) living in the dark cavern completely deprived of eyes. These animals when taken to the light, develop the organ after a few generations. Well, this is not a proof of an "intelligent" behavior of our DNA since the coding must be already present, and so only activated. But it shows some kind of "reaction"...

Originally posted by mattison0922This isn't generally how Darwinian Theory is thought to operate, it's generally thought to operate via selective pressure on random variations that result from processes such as genetic recombination, and random mutation....

My university was about bio-technology, and now I working in computer science... so it's hard for me not to make a comparison:
in a few year of existence, the "programming languages" moved from the 1st to 4th generation(I won't describe it here, it's off topic), and some research about IA, that imitate the life style(neural network), are able to reprogram themself to obtain better result. And this only after a few year of research...
The life on earth got billions of year to reach the same (or better) level...

BTW, I think what you are referring to with respect to the Mayans is Niacin deficiency. There's lots of niacin present in corn, but is not bio-available unless you prepare the corn via cooking in 'lime water.' I am not sure exactly how you were trying to correlate this with the other stuff, but I am actually intrigued by such things myself. How did they know how to do that? It's sort of interesting, but nothing I've ever really studied in depth.

Yes, it must Niacin deficiency, I couldn't remember the name.
What I mean with this is that our ancestors shows the ability to found unexpected solution to adapt to the local ressources. And so, I don't see any reason why any population wouldn't evolve in any part of the world...

Originally posted by Lillo

About mutation, I remember that there are some species (some kind of lezard. Anyone knows the name?) living in the dark cavern completely deprived of eyes. These animals when taken to the light, develop the organ after a few generations. Well, this is not a proof of an "intelligent" behavior of our DNA since the coding must be already present, and so only activated. But it shows some kind of "reaction"...

Actually, this is extremely interesting, and something I'd not heard of. If you could perhaps find out where you heard that or otherwise, I'd appreciate it I will look into that myself though. That's amazing. I would agree that it shows a 'reaction.' In my own mind it suggests some sort of environmentally induced cue. But like I mentioned... to my knowledge, that's unprecedented at the organismal level... especially, if it's demonstrated that they can regain sight over and over.

My university was about bio-technology, and now I working in computer science... so it's hard for me not to make a comparison:
in a few year of existence, the "programming languages" moved from the 1st to 4th generation(I won't describe it here, it's off topic), and some research about IA, that imitate the life style(neural network), are able to reprogram themself to obtain better result. And this only after a few year of research...
The life on earth got billions of year to reach the same (or better) level...

IMO, this sounds like an argument from an Intelligent Design (ID) perspective, which is not in opposition to the idea of billions of years... not trying to hijack your thread to an ID discussion

Yes, it must Niacin deficiency, I couldn't remember the name.
What I mean with this is that our ancestors shows the ability to found unexpected solution to adapt to the local ressources. And so, I don't see any reason why any population wouldn't evolve in any part of the world...

Agreed. Irrespective of their origins, humans show a remarkable penchant for adaptation.

Again, I would appreciate it if you could find out more about this regrowing eyes thing... I will look myself as well. Thanks.

Originally posted by mattison0922
If you could perhaps find out where you heard that or otherwise, I'd appreciate it

It was a reportage on TV... about 10 years ago. I looking for it on google... but it's easy with all the sites about "Eyes of the beholder" and so on

I found a fish that has a similar reaction to darkness in a few generation.
Article

[edited to correct url codes -nygdan]

[edit on 21-12-2005 by Nygdan]

About mutation, I remember that there are some species (some kind of lezard. Anyone knows the name?) living in the dark cavern completely deprived of eyes.

? That sounds interesting.

From the article it looks like they are talking about the cave type being able to mate with the non-cave 'ancestral' type and produce viable offspring.

Despite being blind, the cavefish still retains its original circuit of eye-building genes.

Fascinating.

Still trying to digest this information and process the implications.

Originally posted by Nygdan
From the article it looks like they are talking about the cave type being able to mate with the non-cave 'ancestral' type and produce viable offspring.

Despite being blind, the cavefish still retains its original circuit of eye-building genes.

Fascinating.

Not sure if you missed this or not, Nygdan but the article further states that

Special Emphasis by mattison0922
The most startling thing he has found is that cavefish grow eyes for quite a long time. Just as in surface fish, the brains of cave fish embryos bulge out to the sides, stretching into stalks that end in cups. A simple retina and lens begin to form, and growing nerves begin to link the retina to the visual centers of the fish brain....

if they transplanted just the lens of a surface fish into the eye of a cave fish, the cave fish grew a completely normal eye. What's more, the transplant triggered new nerve fibers to project from the retina to the brain, and the part of the cave fish's brain that handles vision even grew.

This absolutely blows my mind. This idea further supports a topic that you and I have touched on the past, Nygdan. Specifically the idea that genomes receive information from the environment and respond. The fact that these fish Can regrow normal eyes AND the associated nerve structure just by receiving a message from normal eye tissue, suggests that there is much more at work in these blind fish examples than traditional evolutionary theory would have us believe.

Fascinating

Agreed. Completely

Originally posted by mattison0922
Specifically the idea that genomes receive information from the environment and respond.

It'd be really interesting to see some sort of genechip analysis of an individual before and after such an implant from these new nerves.