Posted on 08/16/2006 11:38:54 AM PDT by PatrickHenry
One of the fastest-evolving pieces of DNA in the human genome is a gene linked to brain development, according to findings by an international team of researchers published in the Aug. 17 issue of the journal Nature.
In a computer-based search for pieces of DNA that have undergone the most change since the ancestors of humans and chimps diverged, "Human Accelerated Region 1" or HAR1, was a clear standout, said lead author Katie Pollard, assistant professor at the UC Davis Genome Center and the Department of Statistics.
"It's evolving incredibly rapidly," Pollard said. "It's really an extreme case."
As a postdoctoral researcher in the lab of David Haussler at UC Santa Cruz, Pollard first scanned the chimpanzee genome for stretches of DNA that were highly similar between chimpanzees, mice and rats. Then she compared those regions between chimpanzees and humans, looking for the DNA that, presumably, makes a big difference between other animals and ourselves.
HAR1 has only two changes in its 118 letters of DNA code between chimpanzees and chickens. But in the roughly five million years since we shared an ancestor with the chimpanzees, 18 of the 118 letters that make up HAR1 in the human genome have changed.
Experiments led by Sofie Salama at UC Santa Cruz showed that HAR1 is part of two overlapping genes, named HAR1F and HAR1R. Evidence suggests that neither gene produces a protein, but the RNA produced by the HAR1 sequence probably has its own function. Most of the other genes identified by the study also fall outside protein-coding regions, Pollard said.
Structurally, the HAR1 RNA appears to form a stable structure made up of a series of helices. The shapes of human and chimpanzee HAR1 RNA molecules are significantly different, the researchers found.
RNA is usually thought of as an intermediate step in translating DNA into protein. But scientists have begun to realize that some pieces of RNA can have their own direct effects, especially in controlling other genes.
The proteins of humans and chimps are very similar to each other, but are put together in different ways, Pollard said. Differences in how, when and where genes are turned on likely give rise to many of the physical differences between humans and other primates.
Researchers at UC Santa Cruz, the University of Brussels, Belgium and University Claude Bernard in Lyon, France, showed that HAR1F is active during a critical stage in development of the cerebral cortex, a much more complicated structure in humans than in apes and monkeys. The researchers found HAR1F RNA associated with a protein called reelin in the cortex of embryos early in development. The same pattern of expression is found in both humans and rhesus monkeys, but since the human HAR1F has a unique structure, it may act in a slightly different way. Those differences may explain some of the differences between a human and chimp brain.
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The chimpanzee genome was published in Nature in 2005, showing that the DNA sequences of humans and chimps are more than 98 percent identical. The current work was funded by the Howard Hughes Medical Institute, the U.S. National Institutes of Health and other agencies.
"The current work was funded by"
a thread last night
Notice that there is no way to prove any piece of this sentence. You can't prove that it has evolved or that it is evolving, you can't prove what this gene has to do with brain development. The word 'linked' is meaningless. There is also no way to show how a gene controls the development of anything outside the cell.
Brain gene shows dramatic difference from chimpDemocrat to human.
Whatever part of Islam derives from Judaism or Christianity, the business about God turning men into apes is purely Koranic.
Greek warrior Spartan civilization. Weakling infants were left in the mountains to die.
The Republic, Book 5, Section 1. Plato recommended state-supervised selective breeding of children.
The topic of culture in animals is quite intriguing.
Interesting little things those genes. Like little machines made in a factory even.
If you don't want someone to find something, hide it in such a pile of extraneous and irrelevant stuff that they will never take the time to sort it out and you can claim they are stupid or lazy. Is that what it takes for evolution worshippers to keep their self-image together.
You constantly post barrages of links to pages which themsleves are composed of barrages of links to pages with yet more links. Yet you'll give the link some seemingly straitforward title like "The Evidence for human evolution." As a healthy skeptic of neo-Darwinism and hater of leftist propganda tactics I'm constantly disappointed when I actually try to listen to the Darwinists or read what they really have to say.
Here is the only intelligent site on these issues from an evolutionist I've ever found. He honestly interacts with the best of the anti-Darwin world.
http://home.wxs.nl/~gkorthof/
Deliberate ignorance is such a sad thing to witness.
They also have an uncanny ability to best professional stockpickers simply by throwing darts at stock listings, even when blindfolded!
Without having read this thread yet, but having read many a preceding one, I can guess the reactions to this by many in the FR community. If a scientist as a matter of linguistic convenience uses a word that implies design, that in itself is somehow proof of ID. However, if as in the above-quoted case he flat-out says that something has been and still is evolving, that only shows he's letting his preconceptions, suppositions, assumptions, and materialist worldview run away with his logic.
And, they show they are even smarter than us by not giving any of their income to those stockpickers.
As Darwin knew (and Hitler didn't) the more variability there is in a species, the better its chances of survival over the long run. Hitler's scheme was almost a guarantee of eventual extinction. A sad example of attempted "intelligent design."
I'd double-check that.
'I'll have some fish and chimps, please'.
Somebody had to say it.
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