Posted on 11/15/2005 8:25:44 AM PST by balrog666
'Perception' gene tracked humanity's evolution, scientists say
A gene thought to influence perception and susceptibility to drug dependence is expressed more readily in human beings than in other primates, and this difference coincides with the evolution of our species, say scientists at Indiana University Bloomington and three other academic institutions. Their report appears in the December issue of Public Library of Science Biology.
The gene encodes prodynorphin, an opium-like protein implicated in the anticipation and experience of pain, social attachment and bonding, as well as learning and memory.
"Humans have the ability to turn on this gene more easily and more intensely than other primates," said IU Bloomington computational biologist Matthew Hahn, who did the brunt of the population genetics work for the paper. "Given its function, we believe regulation of this gene was likely important in the evolution of modern humans' mental capacity."
Prodynorphin is a precursor molecule of the neurotransmitters alpha-endorphin, dynorphin A, and dynorphin B, collectively called opioids because their action is similar to stimulatory effects caused by the drug opium.
The notion that humans are more perceptive than other primates would hardly be news. But the list of genes known to have tracked or guided humanity's separation from the other apes is a short one. Genes controlling the development of the brain almost always turn out to be identical or nearly so in chimpanzees and human beings. And as it turns out, the protein prodynorphin is identical in humans and chimps.
It's the prodynorphin gene's promoter sequence -- upstream DNA that controls how much of the protein is expressed -- where the big differences are. "Only about 1 to 1.5 percent of our DNA differs from chimpanzees," Hahn said. "We found that in a stretch of DNA about 68 base pairs in length upstream of prodynorphin, 10 percent of the sequence was different between us and chimps."
Hahn said this "evolutionary burst" is responsible for differences in gene expression rates. When induced, the human prodynorphin gene was 20 percent more active than the chimpanzee prodynorphin gene. Past research has also observed variation in expression levels within humans.
This report supports a growing consensus among evolutionary anthropologists that hominid divergence from the other great apes was fueled not by the origin of new genes, but by the quickening (or slowing) of the expression of existing genes.
Hahn and his colleagues at Duke University, University College London and Medical University of Vienna first became interested in primate prodynorphin after noticing an unusual amount of variation in the human version's promoter. The scientists decided to examine the prodynorphin gene in human beings around the world and in non-human primates to see whether such variation was commonplace and whether that variation affected gene expression.
The group found a surprisingly large amount of genetic variation among humans within the prodynorphin gene's promoter. They examined prodynorphin genes from Chinese, Papua New Guineans, (Asian) Indians, Ethiopians, Cameroonians, Austrians and Italians.
The group also sequenced and cloned prodynorphin genes from chimpanzees, gorillas, orangutans, rhesus macaques, pigtail macaques and guinea baboons. The researchers found that high genetic variation in the prodynorphin promoter was unique to humans. Other primates' promoters were far more homogeneous.
Exactly how prodynorphin influences human perception is unknown. Evidence for its various effects comes entirely from clinical studies of people who have mutations in the gene. Past clinical studies have also indicated a positive correlation between lower prodynorphin levels in the brain and susceptibility to cocaine dependence.
Matthew Rockman, David Goldstein and Gregory Wray (Duke University); Nicole Soranzo (University College London); and Fritz Zimprich (Medical University of Vienna) also contributed to the research. It was funded by grants from the National Science Foundation, NASA, the Royal Society, and the Leverhulme Trust (U.K.).
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Just a minor clarification, which is largely irrelevant and you didn't really make any mistake, but I like to hear myself type..
Genetic Algorithms don't produce program code. An individual in a genetic algorithm is represented as a string of "genes" that encode its phenotype. The result of a GA is the most optimal string representation found. So GA's are closest to natural evolution, which is why I find them more interesting than Genetic Programming, which does use computer programs as a representation. So in Genetic Prgoramming an individual is represented as a prgram and the actual program is mutated and evaluated for the selection process. In this case the output will be the most optimal program found.
GP's are not GA's - they are both different applications of evolutionary computation.
You could have asked Magellan's crew, or the confederate soldiers wintering at Fredericksburg (1862-63) or Petersburg (1864-65), or any else who's ever had scurvy about that.
Hmm... Could it be they just didn't have a proper nutritional diet?
You can also die if you don't eat. Is that also a 'broken' gene?
It's amazing the arrogance of some...
My cat wouldn't eat fruit on a bet. Once in a blue moon he'll eat some leafy stuff just to throw up. Even as do cats and dogs, we have a gene for making vitamin C so that we don't have to eat it. But ours is broken.
Thus your response is so far inadequate. You are refusing to see the problem so you don't have to answer it. That doesn't look very convincing to anyone who has already seen the problem for himself and was waiting for a real answer.
It's amazing the powers some attribute to willful ignorance.
I'm told the "goto" statement still exists in C++, but that it hasn't actually been observed.
C++ compilers will compile C statements and there is a "goto" in C.
Not if you want to keep your job.
C is the only thing in the computer world that I truly loved without reservation.
Humanity.. Apes on Drugs.. Wow.. What a concept..
DDLE seems to be a work in progress. I'm not thrilled with the interface. I predict it will go through some evolution.
You've obviously never lived in a town where The Grateful Dead played in concert.
It was the reverse polish notation that did it..
( Not any sort of a statement on Garcia, just that it took me a long time to appreciate their musical stylings.. )
That's okay. I'm just trying to keep ahead of the curve.
My rule of thumb was, if you couldn't see the entire function on one screen, it was time to break it up. Obviously switch statements couldn't always follow this rule, but I loathed deeply nested conditionals.
I never used a goto.
I didn't learn about the "goto" statement until my last week of C++ when one of the students mentioned he had come across it in an online tutorial. The instructor acknowledged it could be used, but then told us he'd flunk anyone in the class who included it in his coding. Evidently "goto" is a four-letter word in the programming world...
I did, all the time. It was in my Apple II days, using Apple BASIC. I was young and foolish, and I thought GOTO and GOSUB were wonderful. Now, listening to you guys, I wonder where I went wrong.
The results of the two methods of producing programs are *vastly* different in character and structure, and any programmer could tell at a glance whether a particular program was actually written by a human, or "grown/evolved" via genetic algorithms.
And one can often tell at a glance that 'a particular program was actually written by' an idiot.
It's an unnecessary construct in C. I got into VB and found that onerror goto statements were common.
If you caused an exception in C you were hosed without hope of redemption. I really loved the discipline of managing everything. You never had to worry about buffer overflows because you never allowed them. After a while the coding conventions were automatic.
I once spent a couple weeks writing a regular expression parser as a single recursive function. I did it entirely with pointers. Not a single memory allocation in sight.
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