Posted on 01/23/2006 4:31:58 PM PST by PatrickHenry
Scientists at the Georgia Institute of Technology have found genetic evidence that seems to support a controversial hypothesis that humans and chimpanzees may be more closely related to each other than chimps are to the other two species of great apes – gorillas and orangutans. They also found that humans evolved at a slower rate than apes.
Appearing in the January 23, 2006 issue of the Proceedings of the National Academy of Sciences, biologist Soojin Yi reports that the rate of human and chimp molecular evolution – changes that occur over time at the genetic level – is much slower than that of gorillas and orangutans, with the evolution of humans being the slowest of all.
As species branch off along evolutionary lines, important genetic traits, like the rate of molecular evolution also begin to diverge. They found that the speed of this molecular clock in humans and chimps is so similar, it suggests that certain human-specific traits, like generation time, began to evolve one million years ago - very recently in terms of evolution. The amount of time between parents and offspring is longer in humans than apes. Since a long generation time is closely correlated with the evolution of a big brain, it also suggests that developmental changes specific to humans may also have evolved very recently.
In a large-scale genetic analysis of approximately 63 million base pairs of DNA, the scientists studied the rate at which the base pairs that define the differences between species were incorrectly paired due to errors in the genetic encoding process, an occurrence known as substitution.
"For the first time, we've shown that the difference in the rate of molecular evolution between humans and chimpanzees is very small, but significant, suggesting that the evolution of human-specific life history traits is very recent," said Yi.
Most biologists believe that humans and chimpanzees had a common ancestor before the evolutionary lines diverged about 5-7 million years ago. According to the analysis, one million years ago the molecular clock in the line that became modern humans began to slow down. Today, the human molecular clock is only 3 percent slower than the molecular clock of the chimp, while it has slowed down 11 percent from the gorilla's molecular clock.
This slow down in the molecular clock correlates with a longer generation time because substitutions need to be passed to the next generation in order to have any lasting effect on the species,
"A long generation time is an important trait that separates humans from their evolutionary relatives," said Navin Elango, graduate student in the School of Biology and first author of the research paper. "We used to think that apes shared one generation time, but that's not true. There's a lot more variation. In our study, we found that the chimpanzee's generation time is a lot closer to that of humans than it is to other apes."
The results also confirm that there is very little difference in the alignable regions of the human and chimp genomes. Taken together, the study's findings suggest that humans and chimps are more closely related to each other than the chimps are to the other great apes.
"I think we can say that this study provides further support for the hypothesis that humans and chimpanzees should be in one genus, rather than two different genus' because we not only share extremely similar genomes, we share similar generation time," said Yi.
Even though the 63 million base pairs they studied is a large sample, it's still a small part of the genome, Yi said. "If we look at the whole genome, maybe it's a different story, but there is evidence in the fossil record that this change in generation time occurred very recently, so the genetic evidence and the fossil data seem to fit together quite well so far."
Only those from Nebraska, Man.
That was warpcorebreach who told that lie, not TheBrotherhood. TheBrotherhood lied about Darwin recanting on his deathbead, and lied about Darwin's own family substantiating that false claim.
Yes, in post #438, I admitted confusing the two, and apologized to TheBrotherhood. I'm not too proud to admit my mistakes.
Although TheBrotherhood was quick to point out my error, he refuses to acknowledge his own. He continues to compound his lies by repeating them, even quote-mining from a creationist website!
The level of dishonesty is absolutely staggering. I also suspect a plant - creationists usually hide when you call them on their lies, they don't keep repeating them and repeating them and repeating them.
Funny that you should mention Nebraska. Man, I was just thinking about it.
So now we're stereotyping? "You people" happen to be as varied in outlook and disposition as any other collection of people.
So you admit that you started slinging insults without being provoked because you didn't like somebody's opinion. Interesting.
That was a CRIDer. You are also a CRIDer, right?
(CRIDer=Creo/ID myth believer).
I can usually tell a liberal as soon as they open their mouth, sometimes before.
IOW, you have no actual evidence to support your claim that they are liberals. You're just making it up.
That's OK. Sometimes I can't tell you liars apart.
. I know they are not our closest relative, see the analogies I've posted, so I know the DNA studies are most likely fudged in order to fit a preconceived hypothesis.Just like you "liberals" knew the Mapes Memos were genuine and not forged, so all the font studies done by the bushbots were most likely fudged in order to fit a reconceived hypothesis.
I'm sorry, but you are a "liberal", living by your "hopes and feelings".
Away from caring about teams run by families named "Irsay."
Funny how that is, when you catch someone in a lie....
What's the betting line on his bothering to come back?
I wouldn't give you much for it just now.
Hee hee.
500
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