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."
Liars need good memories.
Dimensio calls everyone a liar, and the only response that ever makes him stop, is to post snippets of current scientists manufacturing data to further their lackluster careers.
Troll-baiting placemarker.
From your tag line: "...Creationism is a cancer on conservatism."
Why do you say that creationism is a cancer on conservatism when the bulk of conservatism is made up of creationists?
What really happened is that Lady Hope seduced Darwin, and afterwords he exclaimed: "Oh, how I regret what I have done!" But she was so demented that she misunderstood.
CarolinaGuitarman is on these crevo threads daily and I don't think he's a troll.
Is this another "historical fact?" The only poll ever attempted on FR showed otherwise. It also showed the only two respondents engaging in massive cheating were creationists.
Anyway, from my home page... Here's something I posted online here on a thread where creationists were squealing at being the target of a crowd of liberal glitterati one enchanted evening at a fund-raiser for the American Museum of Natural History:
I've been telling you creationists not to give the Tom Brokaws of the world a chance to save science and science education from you. Going after science and science education was a bad idea.Look at you on this thread, lying your butt off for all to see. I don't want anyone confusing you with me.Here's the theory. Don't do a bad thing. If you don't, then the Bad Guys don't get to play Good Guy while stopping you. They don't get to tar all of conservatism with the brush of being composed of antiscience witch doctors.
This is becoming the national issue I've wanted to somehow prevent. You're going to kill us in 06 or 08 or both.
He didn't raise it as a possibility, he raised it as a historical fact. That would mean he had evidence that it did happen, not that there's a time window in which it could have.
Roosevelt could have secretly visited Hitler during the War. You can't prove it's not true. That doesn't make it a historical fact.
Continuing Troll-Fest in Progress; Post at your own Risk
Out for a bit.
>Also Darwin could well have made his recantation to Lady hope and only to Lady Hope.
Exactly, RunningWolf.
It's a known fact that Lady Hope visited Darwin several times during a 4-5 day stretch. Darwin could have made his recantation at any hour during those days w/o a member of his family present. Moreover, a recantation and conversion is usually made to another person of the Faith and at a moment when only the two were alone. I've also theorized that it is not unusual for a man who is about to die to repent and to do so at a moment of deep spiritual awakening. It is often at this hour that men often repent and are gifted with that which is unseen.
I already explained to you what is meant by "hour of death." When one speaks of "the hour of death" he/she does not mean at precisely one hour before death. Oftentimes what is meant is the hours or days before certain death. What really controls with the expression "hour of death" is the certainty of death and not the hour preceeding it.
I thought I had made this clear before.
Funny how this troll was dormant until the last one was banned. Almost like they have an entire set of identities to use up and throw away.
Oooo; you've done it now! You've opend up Pandora's Box with that revelation.
I must confess, it is one of the strangest posting histories I've ever seen on FR.... large gaps in the history, several times.
Can't freep while in prison.
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