CNN/AP: DNA study: Human-chimp split was messy

[DeepModem Mom]

DNA study: Human-chimp split was messy
Wednesday, May 17, 2006

NEW YORK (AP) -- Humans and chimps diverged from a single ancestral population through a complex process that took 4 million years, according to a new study comparing DNA from the two species.

By analyzing about 800 times more DNA than previous studies of the human-chimp split, researchers from the Broad Institute of MIT and Harvard were able to learn not just when, but a little bit about how the sister species arose.

"For the first time we're able to see the details written out in the DNA," said Eric Lander, founding director of the Broad Institute. "What they tell us at the least is that the human-chimp speciation was very unusual."

The researchers hypothesize that an ancestral ape species split into two isolated populations about 10 million years ago, then got back together after a few thousand millennia. At that time the two groups, though somewhat genetically different, would have mated to form a third, hybrid population. That population could have interbred with one or both of its parent populations. Then, at some point after 6.3 million years ago, two distinct lines arose....

***

"It's a totally cool and extremely clever analysis," said Daniel Lieberman, a professor of biological anthropology at Harvard. "My problem is imagining what it would be like to have a bipedal hominid and a chimpanzee viewing each other as appropriate mates, not to put it too crudely."...

http://www.cnn.com/2006/TECH/science/05/17/human.chimp.split.ap/index.html

[RobertSeattle]

1. Yep, 1/20/2001 was rough on all of us

:evilgrin:

[acmavm]

6. That's pretty much what I was thinking. We're living a really

BAD version of the planet of the apes.

[RobertSeattle]

7. There was a Good Version?

:evilgrin:

[acmavm]

10. Compared to this one, yes.

[RobertSeattle]

12. Never understood why Charleton Heston didn't win an Oscar

...in Planet of the Apes Movies

[madinmaryland]

2. But the universe is only 6,432 years old!

and evolution is just a theory.

:sarcasm:

BTW, I thought you were mentioning that W and Pickles were splitting up.

[saigon68]

44. He is starting to look like his fore-bearers

[aquart]

3. They all look alike in the dark.

6.3 million years? Cool. Approximately the time of the Ross Ice Shelf formation.

Just as I thought.

[fshrink]

4. To answer the last question, that must be charm and charisma.

[Vinnie From Indy]

5. Jungle love!

"It's a totally cool and extremely clever analysis," said Daniel Lieberman, a professor of biological anthropology at Harvard. "My problem is imagining what it would be like to have a bipedal hominid and a chimpanzee viewing each other as appropriate mates, not to put it too crudely."...


I believe that historical anthropologists have definitively determined that the mating of bipedal hominids and chimpanzees occurred at precisely the same moment in history as humans learning to make alcohol by fermenting grains and such.

[formercia]

14. Now we know the origins of Internet porn.......

I wonder if the early stuff was in black and white. :evilgrin:

[tenshi816]

15. You mean beer goggles? n/t

[Vinnie From Indy]

21. egggzactleee!

Hey baby! Ya hang around here much?

[sarcasmo]

8. I can't wait for Dobson's spin on this story.

[Vogon_Glory]

9. My Take On Human--Chimp Split And The Fallout

I'm convinced that one of the hidden genetic consequences of proto-hominid/proto-chimpanzee interbreeding is that certain humans have a tendency to get as frisky as modern chimpanzees do when they go into estrus. The difference is that those humans don't wait for certain times of the month before they're game for hanky-panky.

:evilgrin:

[Kailassa]

50. I seriously think there is some truth in what you're saying..

Three generations of females in our family have tried the "billings" method of contraception.
(The rhythm method helped along by charts and a thermometer.)

The one thing that achieved was proving that we each tended to ovulate in response to being in the company of a particularly sexy guy, and that would sometimes make us ovulate a second time before having a period. Which explained why women in my family have terribly unpredictable cycles.

And there's the annoyingly inconvenient tendency to fall head over heels in love every spring ...

Looking back at past mates, I can't be too hard on female hominids in those days who paired with chimpanzees. :blush:

[6000eliot]

11. You could always ask Laura Bush.

[truthisfreedom]

13. bah-dum-crash.

[Vidar]

16. All because Poppy mated with a gorilla.

[undeterred]

17. a bipedal hominid and a chimpanzee viewing each other as appropriate mates

Maybe there was a man shortage, so to speak. :evilgrin:

[formercia]

18. Or too many beers

Come closing time, almost anything looks good....

[daleo]

24. This sounds like Tweety

Going on about the chimp's "package".

[TrogL]

48. He obviously doesn't get out much

or spend much time in seedy bars.

I've seen things there a chimpanzee wouldn't mate with.

[Kailassa]

51. But when that's what you see after returning home,

then you know you're in trouble. :-(

[sofa king]

19. Pheromones.

All three of those groups would likely have shared the same or similar pheromones to signal when females were in estrus. Male chimpanzees still rely on scent to know when it's an opportune time to mate. I'll bet proto-hominids did, too, and if it smelled right, they screwed it, bipedal or not.

[Jose Diablo]

43. Sure be an ugly looking kid though

But I imagine mom still loved the kid, even though he/she looked weird.

[superconnected]

20. I believed it more before this explanation.

"The researchers hypothesize that an ancestral ape species split into two isolated populations about 10 million years ago, then got back together after a few thousand millennia. At that time the two groups, though somewhat genetically different, would have mated to form a third, hybrid population. That population could have interbred with one or both of its parent populations. Then, at some point after 6.3 million years ago, two distinct lines arose...."

It sounds like they're grabbing too much.

And, I'm an evolution supporter. I suspect their theorys are going to change a lot though.

[Penance]

26. Here's a thought for you

Just to play Devil's advocate:

Horses and donkeys have a different number of chromosomes, but are closely related animals. They can mate and have viable offspring, although the offspring (a mule) is almost always sterile. Horses have 32 pairs of chromosomes while donkeys have 31 pairs. Chimps compared to humans have an additional pair of chromosomes, but one chromosome in humans is much larger than the corresponding one in chimps. The evidence suggests that this large chromosome is the combination of the two analogous chromosomes that are present in modern apes.

The point is that it may be biologically possible right now for a human and a chimp to have a viable offspring. Humans and chimps are at least as closely related as donkeys and horses are, but no one to my knowledge has actually tried it for obvious reasons. There's no solid biological reason a child between a human and a chimpanzee can't happen unless it's tested and found to be impossible. (note: I'm not actually advocating trying it!)

The main difference between early humans and early chimps would have been pelvic. Australopithecus (proto-Human) had a very chimp-like face and brain-case size compared to modern humans. That also means that Australopithecine females had relatively slim hips compared to modern human females. Modern human babies have very big heads. What do modern human males look at when selecting a mate? To be crude: face, breasts and butt. Breasts, being mostly fatty tissue, don't fossilize well but ancient skulls were much more ape-like and the hips of ancient women were much slimmer. 10 million years ago, these features might well have put them within the acceptable dating range of the ancestors of chimps and vice-versa.

For comparison, the split between the line that gave rise to the genus Homo (us) and the line that gave rise to Pan (chimps) is estimated to be between about 8-5 million years ago. The first fossil species included in the genus Homo (Homo habilis) is about 2.5 million years old. The first modern humans only appeared about 200,000 years ago.

[Nikia]

22. "Two isolated populations...got back together after a few thousand "

The two populations probably wouldn't have speciated at that point. Populations of humans have been in isolation from other populations of humans for much longer than that, Australian aborigines for example.

[Igel]

47. Aborigines haven't been separated

for a few thousand millennia. Upwards of 50k years, but not upwards of 4 million.

[tirechewer]

23. To think...

that we have a direct descendant of the Human-Chimp split as our Preznit. It makes me feel all weird inside.

Oh, and on the last point of how hominid and chimp may have been attracted? Did any of you see the look of wonder and delight that George Bush was giving that yak in Mongolia. He wanted it washed and brought to his tent, so to speak. Long winter nights can make some hominids overlook the tiny differences between themselves and a potential mate.

[SoCalDem]

25. Not that difficult for me to understand

the males would have had no problem mating with "whatever", if they were lonely enough, and the females were too small to resist..

Whatever the offspring looked like, the mother would nurture it..

Human nature is not always all that human :)

[Lydia Leftcoast]

39. And also, we're not talking about present-day homo sapiens

breeding with chimpanzees. We're talking about earlier hominids, maybe "Lucy's" brother or someone.

[Jose Diablo]

45. As Adam said in the Twain story called "Adam's Diary"

He sure missed that watermellon.

But Eve was better, though the funny looking bear that Eve found ate all the time and made strange sounds at all hours of the night.

[TahitiNut]

52. Well, since the X-chromasome shows less differentiation ...

... it's possible that one of the divergent populations developed female (XX) 'mules'. That'd tend to explain it, methinks.

[OKNancy]

27. Kick

[matcom]

28. Humans, chimps may have bred after split

<snip>

Boston scientists released a provocative report yesterday that challenges the timeline of human evolution and suggests that human ancestors bred with chimpanzee ancestors long after they had initially separated into two species.

The researchers, working at the Cambridge-based Broad Institute of Harvard and MIT, used a wealth of newly available genetic data to estimate the time when the first human ancestors split from the chimpanzees. The team arrived at an answer that is at least 1 million years later than paleontologists had believed, based on fossils of early, humanlike creatures.

The lead scientist said that this jarring conflict with the fossil record, combined with a number of other strange genetic patterns the team uncovered, led him to a startling explanation: that human ancestors evolved apart from the chimpanzees for hundreds of thousands of years, and then started breeding with them again before a final break.

''Something very unusual happened," said David Reich, one of the report's authors and a geneticist at the Broad and Harvard Medical School.

The suggestion of interbreeding was met with skepticism by paleontologists, who said they had trouble imagining a successful breeding between early human ancestors, which walked upright, and the chimpanzee ancestors, which walked on all fours. But other scientists said the work is impressive and will probably force a reappraisal of the story of human origins. And one leading paleontologist said he welcomed the research as a sign that new genetic information will yield more clues to our deep history than once thought.

more>>>>>>

http://www.boston.com/news/science/articles/2006/05/18/humans_chimps_may_have_bred_after_split?mode=PF

[rock]

29. Just sayin'

Not implying a thing.

[RC]

30. This cannot be. Everyone knows that Humans are

not animals and would never try to breed with the animals. :sarcasm:

[LaurenG]

31. That totally explains the president!

Good job on finding that bit of news!

[zanne]

35. Dammit!

Two people beat me to it!

[Cooley Hurd]

32. It still happens:

[zanne]

33. That explains Dubya. nt

[liberal N proud]

34. Do I need to say anymore?

[regnaD kciN]

36. A picture's worth a thousand words...

:evilgrin:

[Ganja Ninja]

40. What self respecting chimp would ever lower itself to mate ...

with that?

[Boomer]

37. If sheep aren't safe....

>> "My problem is imagining what it would be like to have a bipedal hominid and a chimpanzee viewing each other as appropriate mates, not to put it too crudely."... <<

That's because he's a nerd and not a manly man who guzzles beer and gets frisky with barnyard animals.

[Bigmack]

38. I'll bet crossbreeding has been tried....

in modern times.

Human/chimp crosses would make some interesting ethical questions. Since they're not human, could they be used for drug testing and medical experiments? Could they be used for repetitive tasks in manufacturing? Used as soldiers and pilots in war?

I think the actual crossing has occurred, and I'm waiting to see the offspring in the next 10 years.

[sofa king]

41. Definitely tried at least once.

In the early days of the Soviet Union, a biologist named Ilya Ivanovich Ivanov perfected artificial insemination techniques for horses and other animals, and reputedly turned his attention to human-ape hybridization. His experiments were repeatedly interrupted by a lack of mature apes to serve as either hosts or sperm donors.

H.G. Wells had of course already tread that ground in 1896 (free book ahoy!) with his novella The Island of Dr. Moreau, which has been made into one decent movie (The Island of Lost Souls, with Charles Laughton) and a whole shitload of bad ones. It also certainly served as the creative impulse for the entertaining video game, Far Cry, which is also likely to be made into a shitty film.

[Bushies gotta go]

42. Obviously a very flawed study

since the world is only 6000 years old, or so I've heard from my friends, the religious right wing. And this study is talking MILLIONS of years? Rubbish!

:sarcasm:

[zara]

46. Continued interbreeding is pretty obvious under evolutionary theory...

The break between species occurs with finality when populations get cut off. Then they diverge enough to make reproductive interbreeding impossible. Hence the important of the Galopagos islands, among myriad other examples.

But now I know why that chimp at the zoo was looking mighty fine : ) !

[KamaAina]

49. Did humans mate with chimps?

And are we their offspring?

http://www.slate.com/id/2141784/

We're the offspring of sex between human and chimp ancestors, according to the latest evolutionary theory. Fossils indicate our ancestors diverged from chimp ancestors 7 million years ago, but genes suggest we were still reproducing with them 6 million years ago. Solution: The two groups split but continued having sex, and we probably descended from the breeding of chimpoid-humanoid females with chimpoid males.

"Chimpoid males"! :rofl: