Evolution study tightens human-chimp connection

EurekAlert (AAAS) ^ | 23 January 2006 | Staff

[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."

[foghornleghorn]

This is a fine example of "scientificobabble" which sounds nice on its face, but carries no meaning. Everything is "related" in the sense that it has DNA. We all breathe air, too.

[Coyoteman]

Here's some help: Did Darwin recant? by Russell M. Grigg.

From www.answersingenesis.org.

(Hint: they don't believe a word of it.)

[Revolting cat!]

You the man! They, the best they can do is accuse you of "lies". The 19th century rationalists. They lost their Marx, their Freud, they're hanging on to their Darwin like a drowning man hangs on to a razor. Desperate and and increasingy frantic these threads have been. We shall see. Fifty years ago the believers in those other two clowns were as sure as themselves as these trolls are today. We shall see. (And I'm no 'creationist', just your garden variety sceptic.)

[TheBrotherhood]

That's the same link from yesterday.

I got that link in my Google search too the other day.

[Coyoteman]

That's the same link from yesterday.

I got that link in my Google search too the other day.

Did you read it?

[onewhowatches]

This is a fine example of "scientificobabble" which sounds nice on its face, but carries no meaning. Everything is "related" in the sense that it has DNA. We all breathe air, too.

This is a fine example of "creationbabble" which sounds nice on its face, but carries no meaning.

[Dimensio]

He read enough to cut a small snippet out of context and present it in a totally dishonest fashion.

[Dimensio]

They, the best they can do is accuse you of "lies".

He made a demonstratably false claim, and continued to repeat it even after documentation showed that not even professional creationist groups believe the claim. When we call him a liar, we do it because he lied.

They lost their Marx, their Freud

What makes you think that Marx or Freud were ever "ours"?

(And I'm no 'creationist', just your garden variety sceptic.)

Yet here you are, acting as cheerleader for someone who has repeated a known and demonstratable lie. Why are you defending someone who has repeatedly lied?

[Dimensio]

I'll try it tomorrow, if I do not forget. Promise. Been busy lately.

I'm sure that you'll present as much research and evidence to support your claim as you did today, yesterday and the day before. Which is to say that you'll lie again and present nothing whatsoever to substantiate your lies.

[TheBrotherhood]

Thanks, Revolting cat!.

You do know the evolutionists' ultimate intent, don't you?

[TheBrotherhood]

>Did you read it?

Yes.

[Dimensio]

You do know the evolutionists' ultimate intent, don't you?

I'm sure that your assessment of our "ultimate intent" is no more factual than your lie about Darwin recanting on his deathbed.

You lied, then lied further to cover it up. Badly. Nothing that you say can ever be trusted.

[TheBrotherhood]

>I'm sure that you'll present as much research and evidence to support your claim as you did today, yesterday and the day before.

I'll try posting those thoughts as they occur to me at the time, but I must warn you that I'm not a scientist.

[DennisR]

But given enough time, anything can happen. Right?...Right?......Right? I work for a large aerospace manufacturer in the Seattle area and am justing waiting for the newest airplane to appear out on the flight line. It is going to be so cool! And Airbus is going to be really behind the eight-ball after that happens!!!!!

[FrogMom]

Didn't we just read, within the last two months, that chimps and humans were FARTHER apart genetically than previously thought?

Make up my mind, would ya?

[Dimensio]

I'll try posting those thoughts as they occur to me at the time, but I must warn you that I'm not a scientist.

Another dishonest cop-out from you. It doesn't take a background in science to do the two minutes of historical research required to learn that the story of Darwin's recanting of his theory is a total lie. Yet despite numerous references tossed your way, you have shamelessly continued to repeat the lie, going so far as to cut a quote out of context from a creationist site that does not agree with your lie.

Do you really believe yourself to be convincing when you lie so obviously and transparently about an event that anyone can expose as false? Why do you continue to repeat a known lie? Are you really so much of a coward that you can't bear to admit that you were mistaken? Seriously, I want to know: I find it incredibly insulting that you expect me or anyone else here -- on either side of the crevo discussion -- to be so stupid as to believe your lies.

[Dimensio]

Didn't we just read, within the last two months, that chimps and humans were FARTHER apart genetically than previously thought?

But even with that as the case, chimps are still genetically closer to humans than to other ape species. There's no contradiction here.

[Dimensio]

But given enough time, anything can happen. Right?...Right?......Right?

No. This is a dishonest creationist strawman of evolution. Only lying creationists claim that evolution makes this claim.

I work for a large aerospace manufacturer in the Seattle area and am justing waiting for the newest airplane to appear out on the flight line.

Why should this happen?

[TheBrotherhood]

Sorry. I'm back.

"I'm sure that your assessment of our "ultimate intent" is no more factual than your lie about Darwin recanting on his deathbed."

An assessment or opinion cannot be a lie since the intent is not decieve, but simply to expression a judgement. Moroever, an opinion does not contradict an already known fact.

[Dimensio]

Where is your "historical evidnce" that Darwin recanted on his deathbed? What references do you have your claim that his "daughter/son" testified that Darwin made such a recanting?