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Neanderthal DNA VS Humans and Chimps (Read 13112 times)
GoodScienceForYou
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Neanderthal DNA VS Humans and Chimps
Mar 24th, 2010 at 8:21pm
 
What conclusions can we draw from Neanderthal DNA?


I have looked at all the evidence I can find about this, including the actual DNA structures and it is not conclusive of anything.

ONLY if you have a pre-belief (brainwashed, indoctrinated) in Evodelusionism can you make any "common ancestor" conclusions.  This pre belief ruins scientists and turns them into nut jobs. 

If anything it looks like Chimps mixed with humans are the "parent" of Neanderthals.  This is what seems to be shown in the DNA.

You must realize that the radiometric dating system is extremely flawed and nearly worthless.  It seems to have some "relativity" but not much.  That means that the older specimens are older, but there is no foundational proof of any user tolerance on the dating.  Like plus or minus a million years or so for anything over one million years, up to 5 million years, and over 10 million + or -  5 million in accuracy,  and anything older than that is completely worthless.  Just go look at the dates on the fossils and you will see this pattern of worthlessness in radiometric dating.

Grin
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Re: Neanderthal DNA VS Humans and Chimps
Reply #1 - Jun 13th, 2010 at 6:27pm
 
A decade after scientists first cracked the human genome, researchers announced in the May 7 issue of Science that they have done the same for Neanderthals, the species of hominid that existed from roughly 400,000 to 30,000 years ago, when their closest relatives, early modern humans, may have driven them to extinction.

Read more: http://www.time.com/time/health/article/0,8599,1987568,00.html#ixzz0qmaKy7CX
Led by ancient-DNA expert Svante Pääbo of Germany's Max Planck Institute for Evolutionary Anthropology, scientists reconstructed about 60% of the Neanderthal genome by analyzing tiny chains of ancient DNA extracted from bone fragments of three female Neanderthals excavated in the late 1970s and early '80s from a cave in Croatia. The bones are 38,000 to 44,000 years old.
(See a story about the jewelry worn by Neanderthals.)
The genetic information turned up some intriguing findings, indicating, for instance, that at some point after early modern humans migrated out of Africa, they mingled and mated with Neanderthals, possibly in the Middle East or North Africa as much as 80,000 years ago. If that is the case, it occurred significantly earlier than scientists who support the interbreeding hypothesis would have expected.
Comparisons with DNA from modern humans show that some Neanderthal DNA has survived to the present. Moreover, by analyzing ancient DNA alongside modern samples, the team was able to identify a handful of genetic changes that evolved in modern humans sometime after their ancestors and Neanderthals diverged, 440,000 to 270,000 years ago.
(See whether humans were responsible for the death of Neanderthals.)
The process of sequencing was painstaking. Among the challenges were eliminating bacterial and fungal DNA, which accounted for 97% of the genetic material in the samples, and guarding against contamination from the researchers, whose DNA might be mistaken for Neanderthals'. Plus, the DNA was so fragmented that the chains were often no longer than 40 or 50 base pairs. "We used half a gram of bones to produce the 3 billion base pairs," Pääbo said in a May 5 press conference. "I really thought until six or seven years ago that it would remain impossible, at least for my lifetime, to sequence the entire genome." New sequencing technologies made it feasible, he said.
Researchers compared the Neanderthal genome with the genomes of five living people: one San from southern Africa, one Yoruba from West Africa, one Papua New Guinean, one Han Chinese and one French person. Scientists discovered that 1% to 4% of the latter three DNA samples is shared with Neanderthals — proof that Neanderthals and early modern humans interbred. The absence of Neanderthal DNA in the genomes of the two present-day Africans indicates that interbreeding occurred after some root population of early modern humans left Africa but before the species evolved into distinct groups in Europe and Asia.
(See a photo gallery celebrating the genius of Darwin.)
The gene flow of Neanderthal DNA into early human DNA was found in only one direction: from Neanderthals to us. The study found no early modern human DNA in the Neanderthal genome. It is not clear whether interbreeding happened a few times among small populations or frequently among large populations; the genetic remnants would look the same with current technology. The Neanderthal DNA appears in the modern human genomes randomly, suggesting it offers no evolutionary benefit and is merely a genetic relic.
Finding any mixture of DNA was a surprise to the team. "We came into the project extremely biased against the idea of gene flow," said Harvard Medical School's David Reich, one of the study's authors, who specializes in examining the relationship between human populations using genomic data.


Read more: http://www.time.com/time/health/article/0,8599,1987568,00.html#ixzz0qmaDX5JR
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Re: Neanderthal DNA VS Humans and Chimps
Reply #2 - Jun 13th, 2010 at 6:29pm
 
The first rough draft of the Neanderthals' genome suggests that they interbred with our own species - but only enough to leave a tiny mark on the genetic code of humans from outside Africa.
"The Neanderthals are not totally extinct," said Svante Pääbo, a geneticist at Germany's Max Planck Institute for Evolutionary Anthropology. "In some of us they live on, a little bit."
Pääbo is the leader of an international team of researchers who worked for four years to extract the genetic code from half a gram of ground-up Neanderthal bone, taken from three separate specimens. The resulting draft sequence, which represents about 60 percent of the entire genome, is unveiled in this week's issue of the journal Science.
The results shed light on the evolution of our own species, Homo sapiens, as well as on the genetic heritage of now-extinct Homo neanderthalensis. When researchers compared the detailed Neanderthal code with that of five modern-day humans from different areas of the world, they found overwhelming similarities. But they also found some scientifically significant differences.
Genetic sequences from the three non-African modern individuals (from Papua New Guinea, China and France) were statistically more likely to be similar to Neanderthals than the sequences from southern Africa and West Africa. That suggests that some interbreeding took place after early humans spread out from Africa, most likely in the Middle East 50,000 to 100,000 years ago, Pääbo and his colleagues said.
But it wasn't all that much interbreeding. Between 1 and 4 percent of the human genome appears to have come from Neanderthals, statistically speaking. The researchers could find no specific string of code could be definitively traced back to them across the full sample. They could not point to any trait that we have inherited specifically from Neanderthals.
Ian Tattersall, an anthropologist at the American Museum of Natural History who was not involved in the research, said the study meshes with earlier findings about the relationship between the two species. Just last month, for example, yet another team of researchers reported similar statistical signs of Neanderthal DNA in samples from modern humans.
"I don't think it changes the picture we already had, that Neanderthals and Homo sapiens were functionally individuated entities," Tattersall told me. "This is what species are about. There may have been a bit of Pleistocene hanky-panky, but nothing that left a clear biological mark on either party."
A tangled tale
Untangling our connection to Neanderthals is tricky on several counts. First, you have to get the Neanderthal DNA.
The species is reflected in the European fossil record as far back as 400,000 years ago, and scientists believe that Neanderthals co-existed with us Homo sapiens types until about 30,000 years ago. Did we kill them off? Were they assimilated into our species' gene pool? Or were they simply ill-suited to cope with changing conditions on Earth?
     
Science / AAAS
     Neanderthal bones come from these four archaeological sites, marked with the approximate dates for the bones' age.
For whatever reason, the Neanderthals left behind a relatively scant record. To conduct their genetic study, Pääbo and his colleagues checked out 21 Neanderthal bone samples that were recovered from Croatia's Vindija Cave. Three bones, thought to date back to around 40,000 years ago, were selected for detailed DNA analysis.
Tiny amounts of powder were extracted from the interiors of the bones with a sterile dental drill, processed with chemicals and run through DNA-sequencing machines. An analysis of the DNA showed that 95 to 99 percent of it was from other organisms - for example, microbes that colonized the bones after the Neanderthals died. But the researchers used special enzymes to separate the signature of Neanderthal DNA from that of microbial (and human) contamination.
Even though the Neanderthal DNA was broken up into small pieces, the researchers sequenced 3 billion base pairs and completed about 60 percent of the genome's jigsaw puzzle.
Humans vs. Neanderthals
Decoding the genome was only part of the job. Comparing that genome with our own genetic code was just as tricky. Neanderthals and the human species are thought to have diverged only 500,000 years ago, which means the two species are close cousins in anthropological terms. In fact, if you compared a particular area of the Neanderthal genome with the corresponding genetic code in a single modern human, there's a chance you'd find more similarities than you'd see between two modern humans.
     
Max Planck Institute EVA
     Most of the Neanderthal genome sequence was retrieved from these three bones, which were found in Croatia's Vindija Cave.
When Pääbo started the project, he didn't think he'd find any evidence of "gene flow" between ancient Neanderthals and humans. After all, an earlier study involving a different kind of genetic code known as mitochondrial DNA showed no such intermixing. "I was probably biased really in the direction that it would not have happened," Pääbo said.
But when the comparison came back with the five modern humans, and the researchers found more similarities between the Neanderthal genome and the non-African genomes, that was a big hint that Neanderthals interbred with ancient humans after they emerged from Africa. "At first I thought it was some kind of statistical fluke," Pääbo said.
The researchers rechecked their results, looked for alternate explanations, and went so far as to do yet another comparison with genomics pioneer Craig Venter's personal code. But the link between Neanderthals and non-Africans held up.
"This was really a surprise to us," said Harvard geneticist David Reich, one of the co-authors of the study.
Case closed?
The question over whether ancient humans ever "did it" with Neanderthals now appears to be resolved, but the draft genome raises more questions that are just as deep. For example, what traits did humans develop that gave them an evolutionary edge over Neanderthals? The researchers found some intriguing clues:
Five genes stood out as different in Neanderthals and modern humans. One of them has to do with how sperm cells whip their tails around. Another relates to wound-healing. Yet another builds a protein for the skin, sweat glands and hair roots. "It's tantalizing to think that the skin changed, but the biological implication of that is not at all clear yet," Pääbo said.
Several genes showed evidence of positive selection in humans as opposed to Neanderthals - including genes linked to schizophrenia, autism and Down syndrome. "This suggests that some of the genes that were positively selected may have had to do with cognitive development. ... It doesn't suggest that Neanderthals had no autism, or that they were more similar to people with autism," Pääbo said.
The researchers also focused on a gene that was linked to development of the frontal part of the skull, the shoulder bone and ribcage. Those are anatomical features where Neanderthals and humans differ, so the researchers said it was a "reasonable hypothesis" that that particular gene, RUNX2, "was of importance in the origin of modern humans."
Researchers are continuing to analyze the Neanderthal genetic data, and they expect to get a clearer picture of the species distinctions as time goes on.
Right now, the coverage of the genome is 1.3x, which means an individual DNA base pair was checked only 1.3 times on average. Pääbo said "our goal for the next two to three years is to come somewhere between 10 and 20x coverage," which would be comparable to the accuracy for a typical human genome. He estimated the cost of the project so far at 2 million to 3 million euros ($2.5 million to $3.8 million), but added that "it will be a lot cheaper to now go on."
Tattersall said the research team's first draft was "a remarkable achievement, and something they should be congratulated for." And he expected that there would be even more remarkable revelations ahead.
"This is the beginning of the story," he told me, "not the end of it."
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Re: Neanderthal DNA VS Humans and Chimps
Reply #3 - Jun 13th, 2010 at 6:33pm
 
Ancient DNA shows interbreeding between Homo sapiens and Neanderthal

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By David Brown
Washington Post Staff Writer
Friday, May 7, 2010
With the help of a pinch of fossil bone dust, scientists have discovered that modern human beings interbred with Neanderthals tens of thousands of years ago, and that 1 to 4 percent of the genes carried by non-African people are traceable to the much-caricatured, beetle-browed cavemen.

THIS STORY
Great-grandma was a Neanderthal
An evolving lineage
The Neanderthal project, which took four years and involved 57 scientists, is the latest and most astonishing example of the recovery of scientifically useful information from ancient DNA.

The new data answer a few of the many questions about modern human beings' relationship with their last big hominin competitors, who died out about 30,000 years ago. The data also hint at what Homo sapiens had -- but Homo neanderthalensis didn't -- that may have made the difference between survival and extinction.

"What this means is that Neanderthals are not totally extinct. In some of us, they live on," said Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Germany, who led the genome reconstruction described in Friday's issue of the journal Science.

The findings show that modern humans and Neanderthals interbred, probably in the Middle East, between about 100,000 and 80,000 years ago, soon after modern humans migrated out of Africa and before they diversified, through chance and natural selection, into the ethnic groups that exist today. That's why northern Europeans, the Chinese and Papua New Guineans carry traces of Neanderthal ancestry, but Africans do not.



The Neanderthal versions of genes differ from the human versions by one or more DNA letters, known as nucleotides, in the string of thousands of letters that make up a gene. The Neanderthal versions are salted through the 20,000-gene human genome in no particular order. Whether they endow their holders with certain traits or hazards isn't known.

On the other hand, there are dozens of genes (and even some long stretches of DNA encompassing numerous genes) that are distinctly different between modern humans and Neanderthals. Whether those differences had real-world consequences when they crept in through mutation eons ago -- and whether they are keys to human success -- are among the tantalizing questions arising from the new research.

"This is a very powerful method for shining light on a really crucial time in human evolutionary history," said Richard E. Green of the University of California at Santa Cruz, who did much of the work as a postdoctoral student in Paabo's laboratory. He and other scientists are eager to study those genes and regions "to understand exactly what changed, and why."

Until recently, the recovery of genetic material from flora and fauna subjected to the elements for 400 centuries was the subject of science fiction. But new methods of toning up degraded DNA, along with fast and accurate nucleotide sequencing, and software that lets researchers assemble the equivalent of a million-piece jigsaw puzzle, have made it possible.

The Neanderthal genes were recovered from three bones excavated in a cave in Croatia about 20 years ago. One is 38,000 years old, another 44,000 years old and one is undated. They appear to be shin bones, and all are from females. They also seem to have been intentionally broken, possibly to get at the marrow to eat.

The researchers removed half a gram of bone powder with a dental drill. More than 95 percent of the DNA in the sample belonged to bacteria and fungi, not to the Neanderthals. The scientists used a variety of techniques to eliminate the microbial DNA, recover the non-microbial DNA through polymerase chain reaction amplification, and assure themselves they had Neanderthal material and not modern human contaminants.

Proto-humans and chimpanzees diverged from each other about 6.5 million years ago. Modern humans and Neanderthals diverged about 300,000 years ago. On a genetic level, Neanderthals and modern humans are almost as closely related as today's ethnic groups are to each other.

But the differences may be important.

The researchers identified 73 genes for which all modern people have the same molecular version but for which Neanderthals have the more ancient, chimpanzee version. Five of the genes have two molecular differences between the human and Neanderthal-and-chimpanzee versions, suggesting there might be something especially distinct about the human version.

One of those genes encodes a protein that helps the sperm cell's flagellum beat. Another is for a protein that seems to be involved in the healing of wounds. A third is for a protein abundant in skin, sweat glands and hair roots. Successful reproduction, survival after injury and the ability to interact optimally with the environment: All are crucial to survival and obvious "targets" for natural selection.

Several other genes in which the human and Neanderthal versions differ are involved in important aspects of physiology and brain function. In damaged form, many of those genes are in turn implicated in human disease.

They include THADA (diabetes); DYRK1A (Down syndrome), NRG3 (schizophrenia) and CADPS2 (autism). One called RUNX2 is involved in deformities of the skull and collarbone -- parts of the skeleton in which modern people and Neanderthals differed visibly.
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