#Did whites come from Neanderthals
5440 Dead, 573 since 1/20/09
[Here you have it, folks. If you're white, it may be because your
ancestors indulged in some hot monkey cave sex.]
Signs of Neanderthals Mating With Humans
Johannes Krause MPI-EVA
The Vindija cave in Croatia where three small Neanderthal bones were
found.
By NICHOLAS WADE
Published: May 6, 2010
Neanderthals mated with some modern humans after all and left their
imprint in the human genome, a team of biologists has reported in the
first detailed analysis of the Neanderthal genetic sequence.
The Neanderthal DNA that Svante Pääbo analyzed came from these three
bones.
The biologists, led by Svante Paabo of the Max Planck Institute for
Evolutionary Anthropology in Leipzig, Germany, have been slowly
reconstructing the genome of Neanderthals, the stocky hunters that
dominated Europe until 30,000 years ago, by extracting the fragments of
DNA that still exist in their fossil bones. Just last year, when the
biologists first announced that they had decoded the Neanderthal genome,
they reported no significant evidence of interbreeding.
Scientists say they have recovered 60 percent of the genome so far and
hope to complete it. By comparing that genome with those of various
present day humans, the team concluded that about 1 percent to 4 percent
of the genome of non-Africans today is derived from Neanderthals. But the
Neanderthal DNA does not seem to have played a great role in human
evolution, they said.
Experts believe that the Neanderthal genome sequence will be of
extraordinary importance in understanding human evolutionary history
since the two species split some 600,000 years ago.
So far, the team has identified only about 100 genes — surprisingly few —
that have contributed to the evolution of modern humans since the split.
The nature of the genes in humans that differ from those of Neanderthals
is of particular interest because they bear on what it means to be human,
or at least not Neanderthal. Some of the genes seem to be involved in
cognitive function and others in bone structure.
“Seven years ago, I really thought that it would remain impossible in my
lifetime to sequence the whole Neanderthal genome,” Dr. Paabo said at a
news conference. But the Leipzig team’s second conclusion, that there was
probably interbreeding between Neanderthals and modern humans before
Europeans and Asians split, is being met with reserve by some
archaeologists.
A degree of interbreeding between modern humans and Neanderthals in
Europe would not be greatly surprising given that the species overlapped
there from 44,000 years ago when modern humans first entered Europe to
30,000 years ago when the last Neanderthals fell extinct. Archaeologists
have been debating for years whether the fossil record shows evidence of
individuals with mixed features.
But the new analysis, which is based solely on genetics and statistical
calculations, is more difficult to match with the archaeological record.
The Leipzig scientists assert that the interbreeding did not occur in
Europe but in the Middle East and at a much earlier period, some 100,000
to 60,000 years ago, before the modern human populations of Europe and
East Asia split. There is much less archaeological evidence for an
overlap between modern humans and Neanderthals at this time and place.
Dr. Paabo has pioneered the extraction and analysis of ancient DNA from
fossil bones, overcoming daunting obstacles over the last 13 years in his
pursuit of the Neanderthal genome. Perhaps the most serious is that most
Neanderthal bones are extensively contaminated with modern human DNA,
which is highly similar to Neanderthal DNA. The DNA he has analyzed comes
from three small bones from the Vindija cave in Croatia.
“This is a fabulous achievement,” said Ian Tattersall, a paleontologist
at the American Museum of Natural History in New York, referring to the
draft Neanderthal genome that Dr. Paabo’s team describes in Thursday’s
issue of Science.
But he and other archaeologists questioned some of the interpretations
put forward by Dr. Paabo and his chief colleagues, Richard E. Green of
the Leipzig institute, and David Reich of Harvard Medical School.
Geneticists have been making increasingly valuable contributions to human
prehistory, but their work depends heavily on complex mathematical
statistics that make their arguments hard to follow. And the statistical
insights, however informative, do not have the solidity of an
archaeological fact.
“This is probably not the authors’ last word, and they are obviously
groping to explain what they have found,” Dr. Tattersall said.
Richard Klein, a paleontologist at Stanford, said the authors’ theory of
an early interbreeding episode did not seem to have taken full account of
the archaeological background. “They are basically saying, ‘Here are our
data, you have to accept it.’ But the little part I can judge seems to me
to be problematic, so I have to worry about the rest,” he said.
In an earlier report on the Neanderthal genome, the reported DNA
sequences were found by other geneticists to be extensively contaminated
with human DNA. Dr. Paabo’s group has taken extra precautions but it
remains to be seen how successful they have been, Dr. Klein said,
especially as another group at the Leipzig institute, presumably using
the same methods, has obtained results that Dr. Paabo said he could not
confirm.
Dr. Paabo said that episode of human-Neanderthal breeding implied by Dr.
Reich’s statistics most plausibly occurred “in the Middle East where the
first modern humans appear before 100,000 years ago and there were
Neanderthals until 60,000 years ago.” According to Dr. Klein, people in
Africa expanded their range and reached just Israel during a warm period
some 120,000 years ago. They retreated during a cold period some 80,000
years ago and were replaced by Neanderthals. It is not clear whether or
not they overlapped with Neanderthals, he said.
These humans, in any case, were not fully modern and they did not expand
from Africa, an episode that occurred some 30,000 years later. If there
was any interbreeding, the flow of genes should have been both ways, Dr.
Klein said, but Dr. Paabo’s group sees evidence for gene flow only from
Neanderthals to modern humans.
The Leipzig group’s interbreeding theory would undercut the present
belief that all human populations today draw from the same gene pool that
existed a mere 50,000 years ago. “What we falsify here is the strong out-
of-Africa hypothesis that everyone comes from the same population,” Dr.
Paabo said.
In his and Dr. Reich’s view, Neanderthals interbred only with non-
Africans, the people who left Africa, which would mean that non-Africans
drew from a second gene pool not available to Africans.
AbortedBaby
These findings should not surprise anyone. .
Our previous administration, including most-assuredly its "leader,"
was palpably full of Neanderthal DNA.
------------
By David Brown
Washington Post Staff Writer
Friday, May 7, 2010; A03
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.
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.
http://www.washingtonpost.com/wp-dyn/content/article/2010/05/06/AR2010050604423.html
Phlip
> Africans, the people who left Africa, which would mean that non-Africans
> drew from a second gene pool not available to Africans.
However, we certainly won't see anyone here indulging in the
psychological links between Creationism and Racism over THIS finding!