1. Denisovans or Denisova hominins an extinct species of human in the genus Homo. In March 2010, scientists announced the discovery of a finger bone fragment of a juvenile female who lived about 41,000 years ago, found in the remote Denisova Cave in the Altai Mountains in Siberia, a cave which has also been inhabited by Neanderthals and modern humans. Two teeth and a toe bone belonging to different members of the same population have since been reported. Analysis of the mitochondrial DNA (mtDNA) of the finger bone showed it to be genetically distinct from the mtDNAs of Neanderthals and modern humans. Subsequent study of the nuclear genome from this specimen suggests that this group shares a common origin with Neanderthals, that they ranged from Siberia to Southeast Asia, and that they lived among and interbred with the ancestors of some present-day modern humans, with about 3% to 5% of the DNA of Melanesians and Aboriginal Australians deriving from Denisovans. DNA discovered in Spain suggests that Denisovans at some point resided in Western Europe, where Neanderthals were thought to be the only inhabitants. A comparison with the genome of a Neanderthal from the same cave revealed significant local interbreeding, with local Neanderthal DNA representing 17% of the Denisovan genome, while evidence was also detected of interbreeding with an as yet unidentified ancient human lineage. Similar analysis of a toe bone discovered in 2011 is underway, while analysis of DNA from two teeth found in layers different from the finger bone revealed an unexpected degree of mtDNA divergence among Denisovans. In 2013, mitochondrial DNA from a 400,000-year-old hominin femur bone from Spain, which had been seen as either Neanderthal or Homo heidelbergensis, was found to be closer to Denisovan mtDNA than to Neanderthal mtDNA.
2.The Denisova Caveis located in southwestern Siberia, in the Altai Mountains near the border with China and Mongolia. It is named after Denis, a Russian hermit who lived there in the 18th century. The cave was originally explored in the 1970s by Russianpaleontologist Nikolai Ovodov, who was looking for remains of cave bears. In 2008, Michael Shunkov from the Russian Academy of Sciences and other Russian archaeologists from the Institute of Archaeology and Ethnology of Novosibirsk investigated the cave. They found the finger bone of a juvenile hominin, dubbed the "X woman" (referring to the maternal descent of mitochondrial DNA) or the Denisova hominin. Artifacts, including a bracelet, excavated in the cave at the same level were carbon dated to around 40,000 BP. Excavations have since revealed human artifacts showing an intermittent presence going back 125,000 years. A team of scientists led by Johannes Krause and Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, sequenced mtDNA extracted from the fragment. The cool climate of the Denisova Cave preserved the DNA. The average annual temperature of the cave remains at 0 °C, which has contributed to the preservation of archaic DNA among the remains discovered. The analysis indicated that modern humans, Neanderthals, and the Denisova hominin last shared a common ancestor around 1 million years ago. The mtDNA analysis further suggested that this new hominin species was the result of an earlier migration out of Africa, distinct from the later out-of-Africa migrations associated with modern humans, but also distinct from the earlier African exodus of Homo erectus. Pääbo noted that the existence of this distant branch creates a much more complex picture of humankind during the Late Pleistocene. This work shows that the Denisovans were actually a sister group to the Neanderthals, branching off from the human lineage 600,000 years ago, and diverging from Neanderthals, probably in the Middle East, 200,000 years later. Later in 2010, a second paper from the Svante Pääbo group reported the prior discovery, in 2000, of a third upper molar from a young adult, dating from about the same time (the finger was from level 11 in the cave sequence, the tooth from level 11.1). The tooth differed in several aspects from those of Neanderthals, while having archaic characteristics similar to the teeth of Homo erectus. They performed mitochondrial DNA analysis on the tooth and found it to have a sequence different from but similar to that of the finger bone, indicating a divergence time about 7,500 years before, and suggesting that it belonged to a different individual from the same population. In 2011, a toe bone was discovered in the cave, in layer 11, and therefore contemporary with the finger bone. Preliminary characterization of the bone's mitochondrial DNA suggests it belonged to a Neanderthal, not a Denisovan. The cave also contains stone tools and bone artifacts made by modern humans, and Pääbo commented: "The one place where we are sure all three human forms have lived at one time or another is here in Denisova Cave."
3. INTERBREEDING. A detailed comparison of the Denisovan, Neanderthal, and human genomes has revealed evidence for a complex web of interbreeding among the lineages. Through such interbreeding, 17% of the Denisova genome represents DNA from the local Neanderthal population, while evidence was also found of a contribution to the nuclear genome from an ancient hominin lineage yet to be identified, perhaps the source of the anomalously ancient mtDNA. Analysis of genomes of modern humans show that they mated with at least two groups of ancient humans: Neanderthals (more similar to those found in the Caucasus than those from the Altai region) and Denisovans. Approximately 4% of the DNA of non-African modern humans is shared with Neanderthals, suggesting interbreeding. Tests comparing the Denisova hominin genome with those of six modern humans – a ǃKung from South Africa, a Nigerian, a Frenchman, aPapua New Guinean, a Bougainville Islander and a Han Chinese – showed that between 4% and 6% of the genome of Melanesians (represented by the Papua New Guinean and Bougainville Islander) derives from a Denisovan population. This DNA was possibly introduced during the early migration to Melanesia. These findings are in concordance with the results of other comparison tests which show a relative increase in allele sharing between the Denisovan and the Aboriginal Australian genome, compared to other Eurasians and African populations; however, it has been observed that Papuans, the population of Papua New Guinea, have more allele sharing than Aboriginal Australians.
4. Svante Pääbo is a Swedish biologist specializing in evolutionary genetics. One of the founders of paleogenetics, he has worked extensively on the Neanderthal genome. Born in Stockholm, 20 April 1955, Pääbo is the son of Estonian chemist Karin Pääbo and biochemist Sune Bergström. Growing up with his mother, he barely knew his father, who shared the Nobel Prize in Physiology or Medicine with Bengt I. Samuelsson and John R. Vane in 1982. He earned his PhD from Uppsala University in 1986. Since 1997, he has been director of the Department of Genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Pääbo is known as one of the founders of paleogenetics, a discipline that uses the methods of genetics to study early humans and other ancient populations. In 1997, Pääbo and colleagues reported their successful sequencing of Neanderthalmitochondrial DNA (mtDNA), originating from a specimen found in Feldhofer grotto in the Neander valley. In August 2002, Pääbo's department published findings about the "language gene", FOXP2, which is lacking or damaged in some individuals with language disabilities. In 2006, Pääbo announced a plan to reconstruct the entire genome of Neanderthals. In 2007, he was named one of TIME Magazine's 100 most influential people of the year. In February 2009, at the Annual Meeting of the American Association for the Advancement of Science (AAAS) in Chicago, it was announced that the Max Planck Institute for Evolutionary Anthropology had completed the first draft version of the Neanderthal genome. Over 3 billion base pairs were sequenced in collaboration with the 454 Life Sciences Corporation. This project, led by Pääbo, will shed new light on the recent evolutionary history of modern humans. In March 2010, Pääbo and his coworkers published a report about the DNA analysis of a finger bone found in the Denisova Cave in Siberia; the results suggest that the bone belonged to an extinct member of the genus Homo that had not yet been recognized, the Denisova hominin. In May 2010, Pääbo and his colleagues published a draft sequence of the Neanderthal genome in the journal Science. He and his team also concluded that there was probably interbreeding between Neanderthals and Eurasian (but not African) humans. There is growing support in the scientific community for this theory of admixture between archaic and anatomically-modern humans, though some archaeologists remain skeptical about this conclusion. In 2014, he published the book Neanderthal Man: In Search of Lost Genomes where he in the mixed form of a memoir and popular science tells the story of the research effort to map the Neanderthal genome combined with thought on human evolution. In 1992, he received the Gottfried Wilhelm Leibniz Prize of the Deutsche Forschungsgemeinschaft, which is the highest honour awarded in German research. Pääbo was elected a member of the Royal Swedish Academy of Sciences in 2000. In October 2009 the Foundation for the Future announced that Pääbo had been awarded the 2009 Kistler Prize for his work isolating and sequencing ancient DNA, beginning in 1984 with a 2,400-year-old mummy. In June 2010 the Federation of European Biochemical Societies awarded him the Theodor Bücher Medal for outstanding achievements in Biochemistry and Molecular Biology. In 2013, he received Gruber Prize in Genetics for ground breaking research in evolutionary genetics.
Where Art and Paleontology Intersect, Fossils Become Faces
By DONALD G. McNEIL Jr.
For his first date with a fellow art student, Viktor Deak suggested “Bodies,” the exhibit of flayed and plasticized humans.
She said yes, even though she had already seen it. He thought that was promising. But it was dinner afterward that convinced him this was the real thing.
“Any woman who could go to ‘Bodies’ with me and then eat a steak,” he said, “and still be dainty and fun and all, was a girl I could be with forever.”
Mr. Deak (pronounced DAY-ahk) and Xochitl Gomez were married at the Bronx Zoo, in the gorilla grotto. Which makes sense, given how much time they spend there. He brings the camera, she totes the big looking glass.
“They know it’s a mirror,” he said of the zoo’s gorilla family. “They come up, make faces, check out their teeth. I’ve gotten some really great shots.”
His interest in gorilla grimaces, like his interest in displays of dissected flesh, is professional. Mr. Deak, 32, is one of the world’s leading paleoartists. If you find yourself face to face in a museum with Homo habilis, Australopithecus afarensis or Paranthropus boisei, you may be looking at his work.
Many of the images of hominids in the new Hall of Human Origins at the American Museum of Natural History are his, as are those in the book “The Last Human,” both of which he did in collaboration with Gary J. Sawyer, the museum’s physical anthropologist.
(Much of Mr. Deak’s work can be seen on his Web site, www.anatomicalorigins.com.)
His 78-foot-long mural showing six million years’ worth of the proto-humans whose bony bits have been found in northeast Africa is coming to Manhattan in June as part of the exhibit “Lucy’s Legacy.” The exhibit’s centerpiece is the fossilized skeleton of Lucy — three million years old, less than four feet tall, hailing from the Afar Depression of Ethiopia and named after the Beatles song “Lucy in the Sky With Diamonds,” which was playing in the camp when she was found in 1974.
But his mural, a vast Photoshop collage, is more fun to ponder than the bones. The background uses thousands of his photos of vegetation, rocks, valleys and outcrops from the South Dakota badlands, the Puerto Rican jungle and the Wyoming prairie. Only one speck of it, a friend’s mother’s safari shot of faraway thorn trees, was actually snapped in Africa. But Ethiopia today, of course, no longer has the lush rainforest and grassy savannah of Ethiopia three million years ago, so Mr. Deak had to improvise. His landscape is filled with ape-men morphed from photos of his sculpted heads overlaid with photos of chimpanzee hair like a late-night hair restoration commercial, each one set atop the body of a human — usually Mr. Deak, his wife, or friends — in a primeval pose, then further adjusted to have longer arms, jutting buttocks or whatever is accurate.
You do not want to be alone in his apartment at night. His shelves have more skulls than a heavy metal album cover, some of them only partly defleshed. Even his little pasta machine is creepy. He uses it to extrude red clay at just the right thickness for face muscles.
There is something lost in time about the place. Maybe it’s the lack of artifacts from any time zone between his fossil racks and his Transformer robot collection.
It’s not just that as an artist, Mr. Deak has little patience for contemporary art. It’s that he disapproves of pretty much everything from the last 100,000 years, the entire Homo sapiens canon.
After all, he says, not only did our immediate ancestors wipe out many big mammals, but they probably killed off and ate some of his favorite objets d’art, including Homo neanderthalensis, erectus and floresiensis.
“Is it any wonder we have a hard time hanging out with our neighbors,” he asks rhetorically after a long discourse on extinctions, “when at one time we went through the whole planet and just cleaned house?”
Mr. Deak is in touch with his inner hominid. His bodybuilding hobby — the dumbbells are on his studio floor — gives him that “don’t mess with me” look sought by all male primates, and he does a mean “Nutcracker Man with a rock” pose from his own mural.
But the threatening mien is belied by his personality, which is both scholarly and a little star-struck. He is in awe of the early paleoartist John Gurche and the novelist and former New York Times reporter John Darnton, whose book “Neanderthal” he carries everywhere, wrapped in plastic.
“I was a strange little kid,” he answers when asked how he got into paleoart. One of his first sculptures was done at a family barbecue, a human skeleton from chicken bones. Other defining moments, he said, included a book of dinosaur illustrations his Budapest grandfather bought for him, seeing Luke Skywalker get a robotic hand and watching an eighth-grade science film of Mr. Gurche playing Pygmalion to a fossil skull. (Mr. Deak was born in Hungary but grew up in Connecticut.)
His big break came when he was a School of Visual Arts student sketching in the natural history museum. A staff member saw his work and introduced him to Mr. Sawyer.
“I could tell he could think three-dimensionally, abstractly and symbolically,” Mr. Sawyer, whom Mr. Deak refers to as his “spiritual mother,” said in a telephone interview. “That’s the kind of student I wanted to work with.”
At his urging, Mr. Deak went to SUNY Downstate Medical School to dissect cadavers.
“I remember one time he called me, his hands were full of guck, and he said, ‘This is fantastic!’ ” Mr. Sawyer said.
Both recall one of Mr. Deak’s early efforts at Homo heidelbergensis. After weeks of work, he showed it to Mr. Sawyer, who studied it silently, then snatched up a scalpel and began stabbing the nose.
“I almost tackled him,” Mr. Deak said. “Then he said, ‘The nose is wrong. Do it again.’ It’s maybe not the way I’d teach a student, but he taught me that no work is sacred, you have to be ready to destroy it.”
Mr. Sawyer didn’t dispute either the event or the point.
“Viktor didn’t have that deep, deep background in anatomy he does now,” he said. “He’s evolved.”
Hazings like that proved a blessing because, in paleontology, photorealism has its nitpickers. Picasso never had to explain that his mistresses weren’t actually cubic, but Mr. Deak has taken grief over as little as a flexed knee. One academic critic who saw his Lucy mural publicly boasted that he himself “had the good fortune to examine Lucy when she was in Donald C. Johanson’s lab in Cleveland, and I can assure you that the anatomy of the lower back, hips, feet and knee and ankle joints all provide clear evidence that those early hominids stood just as erect as we do.”
Mr. Deak replied on the same Web site that he knew perfectly well that Lucy could stand up, but he had depicted her crouching because she was pulling away from a predator — the viewer. She was, he explained, protecting the baby in her arms and about to run off.
To prove his point, he picks up a cast of her skull. The angle of the foramen magnum, the hole where the spine enters the vault, he explains, shows that she could stand erect.
Anatomical decisions aside, there were other advantages to hunching Lucy over, turning her sideways and adding a baby. Besides the added tension, it avoided the distracting Playboy Primate Playmate aspect of his early drafts, which showed Lucy in full-frontal fecundity. Unlike Homo idaltu, a homo sapiens subspecies extinct for a mere 150,000 years who is also in the mural and who sports a spear and a fetching loincloth, Lucy bipedally strode the earth before clothes were invented.
But the real controversy, Mr. Deak said, is in the idea his work represents. When he was waiting tables as a student, he served a family that had just visited the natural history museum. When he said he worked there part time, they were excited — until he said he worked on the Hall of Human Origins.
“They said, ‘Shh, please — don’t say anything around the kids,’ ” he said. “ ‘We believe in a young Earth. We teach our children that we’re made directly in God’s image, and the Earth is about 5,000 years old.’ ”
“Well, did you see the dinosaurs?” he asked.
“ ‘Yes. We tell them these are the creatures that didn’t make it to the Ark.’ ”
“I felt a chill of fear,” Mr. Deak said. “I still do when I think about it. I’ve seen, sometimes firsthand, the evidence that came out of the ground. It’s terrifying that people can look at it and say, ‘It’s not there’ and believe in something that was just dictated to them.”
“But,” he added, “I was a waiter. I wanted a tip. I bit my tongue and just got out of there.”
In all animals, DNA is found in two places: In the nucleus of every cell (except red blood cells, which contain no nucleus or DNA and therefore cannot be affected by viruses) and in mitochondria, small organelles that act as the “batteries” which power individual cells. The 46 chromosomes in a human cell are actually long strands of DNA that have segments called genes. The DNA in a nucleus and the DNA in mitochondria together form the genome of a person/organism.
7. HOMININ vs. HOMINID
• Hominid – the group consisting of all modern and extinct Great Apes (that is, modern humans, bonobos, chimpanzees, gorillas, and orangutans plus all their immediate ancestors).
• Hominin – the group consisting of modern humans, extinct human species and all our immediate ancestors (including members of the genera Homo, Australopithecus, Paranthropus and Ardipithecus).
• Great apes—species in the biological family Hominidae, including humans, bonobos, chimpanzees, gorillas, and orangutans.
Barras, Colin (13 August 2011), "Stone Age toe could redraw human family tree", New Scientist.
Fox, Maggie (24 March 2010), "Possible new human ancestor found in Siberia", Reuters.
Ghosh, Pallab (22 December 2010), Ancient humans, dubbed 'Denisovans', interbred with us, BBC News online, The study shows that Denisovans interbred with the ancestors of the present day people of the Melanesian region north and north-east of Australia. Melanesian DNA comprises between 4% and 6% Denisovan DNA.
Hawks, John (22 December 2010), "The Denisova genome FAQ", John Hawks Weblog.
Rincon, Paul (25 March 2010), DNA identifies new ancient human dubbed 'X-woman', BBC News online.
Shreeve, Jamie (July 2013), "The Case of the Missing Ancestor", National Geographic.
Wade, Nicholas (24 March 2010), "Bone May Reveal a New Human Group", The New York Times.
Wenz, John (27 August 2014), The Other Neanderthal, The Atlantic.
Zimmer, Carl (24 March 2010), Hybrid speculation (blog), Discover.
Zimmer, Carl (22 December 2010), Meet the Denisovans, the newest members of the human tree of life (blog), Discover.
A HUMAN CELL
THE NEANDERTHAL CONNECTION:
NEANDERTHALS AND HOMO SAPIENS SHARE THE RED HAIR GENE
NEANDERTHALS HAD INTRICATE FAMILIAL RELATIONSHIPS
SIX IMPORTANT IDEAS ABOUT NEANDERTHALS:
1. Sophisticated Tool-making
The Levallois technique is a name given by archaeologists to a distinctive type of stone knapping developed by precursors to modern humans during the Paleolithic period. It is named after nineteenth century finds of flint tools in the Levallois-Perret suburb of Paris, France. The technique was more sophisticated than earlier methods of lithic reduction, involving the striking of flakes from a prepared core. A striking platform is formed at one end and then the core's edges are trimmed by flaking off pieces around the outline of the intended flake. This creates a domed shape on the side of the core, known as a tortoise core as the various scars and rounded form are reminiscent of a tortoise's shell. When the striking platform is finally hit, a flake separates from the core with a distinctive plano-convex profile and with all of its edges sharpened by the earlier trimming work. This method provides much greater control over the size and shape of the final flake which would then be employed as a scraper or knife although the technique could also be adapted to produce projectile points known as Levallois points.
2. Did Neanderthals invent the world's first industrial process?(from PBS’s NOVA website)
At some archeological sites, the Neanderthals subjected sticky substances to an elaborate process. Birch bark contains a tacky resin known as pitch that is impossible to extract simply by tapping into the tree, as with pinesap or maple syrup. Instead, the pitch must be separated from the bark by a process known as dry distillation. Chemists have discovered that distilling pitch from birch bark requires an oxygen-free environment and sustained temperatures of over 650° F. How could Neanderthals, with their Stone Age technology, have produced such conditions? If they really did master this complex process, it is hard to resist the conclusion that they must have had language and a sophisticated ability to think and plan ahead.
Evidence indicates that they successfully developed such a technique. The first discovery was made in 1963 at Kínigsaue, in then-East Germany. This was the site of an ancient lakeside hunting camp, from which Neanderthals had hunted now extinct Ice Age creatures such as mammoth and woolly rhino as well as red deer, horses, and reindeer. Two small, hardened lumps of black material were found during the dig, one bearing a fingerprint and the other the impression of a wooden haft or handle.
In 2001, the lumps were dated to at least 40,000 years ago and were shown to have the chemical signature of birch bark pitch produced by the dry distillation process. Much older evidence was found at the Campitello quarry in central Italy. Here, the remains of an extinct elephant lay close to two large lumps of black pitch, which covered the end of two stone flakes crafted in a typical Neanderthal style. The Campitello find dates back over 200,000 years, a remarkably early origin for this complex process. A third Neanderthal site at Inden-Altdorf, overlooking the Inde River in Germany and dating to around 128,000 to 115,000 years ago, features more than 80 stone tools flecked with black material, but the chemical analysis indicating that this was distilled pitch requires further confirmation.
But the archaeologists at Inden-Altdorf found an important clue: upon analyzing the pitch smeared on Neanderthal tools at the site, they detected traces of potassium, sulfur, and calcium, evidence that the material had been directly exposed to fire and ash during its manufacture. After some practical experiments, the team proposed that the Neanderthals had invented the following procedure: first, wrap a long strip of birch bark around a small pebble so that it forms a cigar-shaped roll. Next, dig a narrow pit, then set light to one end of the roll and place the burning end at the bottom of the pit. In the confined space at the bottom of the pit, the smoldering bark quickly uses up oxygen and causes the pitch to "sweat," or condense, out of the roll of bark onto the surface of the pebble. While still hot, the pitch is a sticky liquid that can be used immediately as glue.
Simple though it sounds in theory, the technique is highly challenging in practice. Procuring pitch today with Stone Age methods obviously calls for careful attention and considerable skill and judgment. Too low a temperature, and the bark fails to produce any pitch; too high, and the bark becomes hard and brittle; with too much oxygen, the bark burns up. As the experimental tests have shown, the temperature of the fire must be constantly monitored in varying wind conditions, the birch bark must be buried correctly with oxygen excluded and removed from the fire at the right time. Archaeologist Wil Roebroeks, who witnessed Palmer's NOVA experiment, comments that its failure underscores the complexity of the process, which "goes to show that they [the Neanderthals] were very capable pyrotechnologists. We're still learning how they did it a quarter of a million years ago."
Roebroeks adds that the significance of the Neanderthal pitches should not be overblown. "After all, they were produced by hunter-gatherers who survived in western Eurasia for hundreds of thousands of years in a wide variety of environments, successfully exploiting a wide range of mammals and other resources...That they discovered a trick or two which we are unable to reproduce nowadays should not come as a surprise—unless of course one assumes that they were 'complete idiots,' lacking the flexibility and learning capacities of other primates."
While Roebroeks warns about making too much of the glue finds, for other archaeologists, the mere fact that Neanderthals could make multi-part tools and weapons argues that they were capable of planning in depth, coordinating several tasks at once, and conceptualizing past and future. No single category of evidence can decide the case for the status of the Neanderthal mind, but the intriguing story of birch bark pitch joins a growing list of discoveries that indicate we may have underestimated the closeness of our bond with our long-vanished relatives from the Ice Age.
1. Broca's area (or the Broca area) is a region in the frontal lobe of the dominant hemisphere (usually the left) of the hominin brain with functions linked to speech production.
2. An endocast is the internal cast of a hollow object, often specifically used for endocasts of the cranial vault. They compliment the use of MRI’s and CAT scans to determine the shape and function of the brain within a skull.
B. GENETIC EVIDENCE:
1. FOXP2 (Forkhead box protein P2) is a protein that, in humans, is encoded by the FOXP2 gene and is required for proper development of speech and language.
2. Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique. Segments of DNA that pass on these instructions are called genes.
Genes are segments of DNA. The twisted double backbone of the DNA “ladder is connected with four nitrogen-bas molecules that form rungs of the ladder. Those four molecules are ALWAYS connected C to G and A to T.
DNA, or deoxyribonucleic acid, is a very long, thin molecule that is in the nucleus of most of our body's cells. It is constructed like a ladder (also called a double helix). Each rung on the ladder consists of two smaller molecules and all the rungs are spaced apart equally. Although each rung has only two molecules, there are only four different kinds of molecules used in the rungs, so each rung has two of four different kinds of molecules. There are approximately 3,000,000,000 rungs on the DNA ladder.
Each one of the rungs on the DNA ladder is like a letter on the page of a book - it means something in combination with the other rungs. Taken together the rungs are a language and they describe various things, one of which is the chemical formulas for approximately 90,000 proteins and enzymes that are essential to our body:
"The human genome contains approximately 3 billion of these base pairs, which reside in the 23 pairs of chromosomes within the nucleus of all our cells. Each chromosome contains hundreds to thousands of genes, which carry the instructions for making proteins. Each of the estimated 30,000 genes in the human genome makes an average of three proteins." (The Human Genome Project Completion: Frequently Asked Questions (National Human Genome Research Institute, 2010): HTTPS://WWW.GENOME.GOV/11006943
Imagine that 3 billion Aces, 3 billion Kings, 3 billion Queens and 3 billion Jacks are all arranged in thousands of different groups. If these cards were arranged in groups of four in one long line that is four cards thick and 3 billion cards long, the line of cards would circle the world approximately 6 times.
3. Hybridization: When our Homo sapiens ancestors first migrated out of Africa around 50,000 years ago, they were not alone. At that time, at least two other species of hominin cousins walked the Eurasian landmass—Neanderthals and Denisovans. As our modern human ancestors migrated through Eurasia, they encountered the Neanderthals and interbred. Because of this, a small amount of Neanderthal DNA was introduced into the modern human gene pool. Everyone living outside of Africa today has a small amount of Neanderthal in them, carried as a living relic of these ancient encounters. A team of scientists comparing the full genomes of the two species concluded that most Europeans and Asians have between 1 to 4 percent Neanderthal DNA. Indigenous sub-Saharan Africans have no Neanderthal DNA because their ancestors did not migrate through Eurasia.
4. ART AND RITUAL
An engraving found at a cave in Gibraltar may be the most compelling evidence yet for Neanderthal art. The pattern, which bears a passing resemblance to the grid for a game of noughts and crosses, was inscribed on a rock at the back of Gorham's Cave.
Mounting evidence suggests Neanderthals were not the brutes they were characterized as decades ago. But art, a high expression of abstract thought, was long considered to be the exclusive preserve of our own species. The scattered candidates for artistic expression by Neanderthals have not met with universal acceptance. However, the geometric pattern identified in Gibraltar, on the southern tip of Europe, was uncovered beneath undisturbed sediments that have also yielded Neanderthal tools. Details of the discovery by an international team of researchers has been published in the journal PNAS.
There is now ample evidence that Neanderthal intellectual abilities may have been underestimated. Recent finds suggest they intentionally buried their dead, adorned themselves with feathers, painted their bodies with black and red pigments, and consumed a more varied diet than had previously been supposed. One of the study's authors, Prof Clive Finlayson, director of the Gibraltar Museum, said the latest find "brings the Neanderthals closer to us, yet again".
Today, the sea is a short distance away, but when the cave was first inhabited, the shore was several kilometres away. Previous candidates for Neanderthal cave art exist, including motifs from caves in northern and southern Spain. Possible jewelry has been found at a site in central France, and there are even claims Neanderthals were responsible for an early musical instrument - a bone "flute" found at Divje Babe in Slovenia.
These proposed flickerings of abstract thought among our ancient relatives have all proven controversial. But the authors of the PNAS study went to great lengths to demonstrate the intentional nature of the Gorham's Cave design. In order to understand how the markings were made, experimental grooves were made using different tools and cutting actions on blocks of dolomite rock similar to the one at Gorham's cave. The method that best matched the engraving was one in which a pointed tool or cutting edge was carefully and repeatedly inserted into an existing groove and passed along in the same direction. This, the authors argue, would appear to rule out an accidental origin for the design, such as cutting meat or fur on top of the rock.
"[Dolomite] is a very hard rock, so it requires a lot of effort to produce the lines," he told BBC News. The archaeologist estimates that the full engraving would have required 200-300 strokes with a stone cutting tool, taking at least an hour to create. "If you did it in a single session, you would most probably injure your hand, unless you cover your tool with a piece of skin," he said.
Prof d'Errico explained that the rock was in a very visible location in the cave and that the engraving would have stood out to any visitors.
"It does not necessarily mean that it is symbolic - in the sense that it represents something else - but it was done on purpose," he said.
Clive Finlayson said team members deliberately avoided speculation in their scientific paper as they wanted it to be a "watertight" description of the discovery. But, he explained: "One intriguing aspect is that the engraving is at the point in the cave where the cave's orientation changes by 90 degrees. "It's almost like Clapham Junction, like it's showing an intersection. I'm speculating, but it does make you wonder whether it has something to do with mapping, or saying: 'This is where you are'."
Prof d'Errico added: "It's in a fixed location so, for example, it could be something to indicate to other Neanderthals visiting the cave that somebody was already using it, or that there was a group that owned that cave."
The researchers also carried out an analysis of the likely position of the person when they were making the engraving, and whether it was likely to have been made by a left- or right-hander, but they have decided not to publish these results for the time being.
The engraving was first spotted in July 2012 by Francisco Giles Pacheco, an eagle-eyed team member who is director of the Archaeological Museum of El Puerto Santa Maria, Spain.
Sediments covering the engraving have previously yielded stone tools made in the Mousterian style, which is considered diagnostic of Neanderthals. However, other researchers note that such artefacts turn up in North Africa, where there is no trace of habitation by Neanderthals. They have previously reasoned that if Homo sapiens made the Mousterian tools in Africa, they might also be responsible for the ones in Gibraltar.
Some 28km of sea separates Gibraltar from the coast of North Africa, and if you look south from the Rock on a clear day, it's hard to miss Jebel Musa - part of Morocco's Rif mountains - rising above the horizon. However, Prof Finlayson says there is no evidence that modern humans made the crossing until much later. In addition, he points out, Mousterian tools are associated with Neanderthal skeletal remains at the Devil's Tower site in Gibraltar.
Another possibility is that Neanderthals were imitating the behaviour of modern humans they'd come into contact with. While Homo sapiens was in Europe by around 45,000 years ago, Prof Finlayson says the moderns reached southern Iberia later than some other regions, casting doubt on the copycat idea.
But Dr Matt Pope, a Palaeolithic archaeologist at University College London, who was not involved with the latest study, was less convinced.
"The engravings do appear intentional and it's hard to easily envisage a purely functional explanation for them. Consequently it's useful to consider these structured scratches as deriving from abstract or symbolic thought," he told BBC News.
"But linking them directly to Neanderthal populations, or proving Neanderthals made them without any contact with modern humans is harder. The dates presented here are indirect, referring to material from within sediments covering the engravings and not the marks themselves.
"Given the dates also span a period when we know modern humans have reached Europe, a period where we have unresolved 'transitional' archaeological evidence difficult to attribute to either population, I'd be cautious in accepting Neanderthal authorship."
Hypotheses on the fate of the Neanderthals include a failure or inability to adapt to climate change, competitive exclusion, or extinction by encroaching anatomically modern humans, who arrived in Europe long after Neanderthals had settled there. Neanderthal hybridization with early modern human populations is also considered a viable hypothesis. Some interbreeding took place in western Asia about 50,000 to 60,000 years ago, as evidenced by 1 to 4 percent of the material of genomes carried by non-African people living today.
Regionally developed ecotypes (such as European Homo neanderthalensis) can be threatened with extinction when new alleles or genes (such as those of Homo sapiens) are introduced to alter that ecotype. This is sometimes called genetic mixing. An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the genetic locus on a chromosome. Humans are called diploid organisms because they have two alleles at
each genetic locus, with one allele inherited from each parent. A locus (plural loci), in genetics, is the specific location or position of a gene on a chromosome. Each chromosome carries many genes; humans’ estimated coding genes are 20,000—25,000, on the 23 different chromosome pairs.
Hybridization and introgression of new genetic material can lead to the replacement of local genotypes if the hybrids are more fit and have breeding advantages over the indigenous ecotype or species. These hybridization events can result from the introduction of non native genotypes by humans or through habitat modification, bringing previously isolated species into contact. Genetic mixing can be especially detrimental for rare species in isolated habitats, ultimately affecting the population to such a degree that none of the originally genetically distinct population remains.
Scientists have discovered a novel receptor, which allows the immune system of modern humans to recognize dangerous invaders, and subsequently elicits an immune response. The blueprint for this advantageous structure was in addition identified in the genome of Neanderthals, hinting at its origin. The presence of this receptor in Europeans but its absence in early humans suggests that it was inherited from Neanderthals.
Neanderthals probably lived many hundreds of thousands of years in Europe during which time they developed the HLA receptor that provided them with immunity against many pathogens. This means that different to our ancestors from Africa, the Neanderthals which were resident in Europe, carried this receptor on their immune cells. That was a “distinct evolutionary advantage,” says an immunobiologist from the University of Bonn, who presumes that we modern humans in Europe owe this advantageous receptor to the Neanderthals.
Neanderthals and other extinct humans like the Denisovans might have endowed some of us with the robust immune systems we enjoy today, scientists now find. These genetic gifts might have helped our species as we expanded out of Africa, investigators added. Although we modern humans are the only surviving members of our lineage, others once roamed the Earth, including familiar Neanderthals and the newfound Denisovans, who lived in what is now Siberia. Genetic analysis of fossils of these extinct lineages has revealed they once interbred with our ancestors, with recent estimates suggesting that Neanderthal DNA made up 1 percent to 4 percent of modern Eurasian genomes and Denisovan DNA made up 4 percent to 6 percent of modern Melanesian genomes.
(Bottom line: When we examine ancient DNA from Africa, samples LACK the HLA receptors; when we examine samples from Europe and Asia, they contain the HLA receptor—probably inherited from Neanderthals, Denisovans, and a third species yet to be named (who also interbred with each other most likely.)