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Tag Archives: Charles Q. Choi

Ancient mouse-size creature uproots mammal family tree

An illustration of Haramiyavia, the earliest known proto-mammal, whose identity is based on a reconstruction of its 210-million-year-old fossil jaw (superimposed on bottom illustration). (April Neander)

An illustration of Haramiyavia, the earliest known proto-mammal, whose identity is based on a reconstruction of its 210-million-year-old fossil jaw (superimposed on bottom illustration). (April Neander)

Three-dimensional computer models of fossils from a tiny mouse-size creature that lived about 210 million years ago in what is now Greenland clear up a long-standing mammal mystery.

The high-tech analysis of the fossils suggests that mammals originated more than 30 million years more recently than previously suggested, the researchers say.

Paleontologists analyzed fossils of haramiyids, extinct relatives of modern mammals that lived about 210 million years ago. For decades, researchers only had isolated teeth from haramiyids, stymying investigations into where these creatures fit on the mammalian family tree. [See Images of 2 Tiny Early Mammals from China]

This uncertainty about where haramiyids belonged raised two possibilities. One was that haramiyids were crown mammals — the branch of the mammal family tree that all modern mammals descend from — suggesting that mammals began to diversify more than 210 million years ago in the Triassic Period. The other was that haramiyids occupied a separate branch at the base of the mammal family tree, suggesting instead that mammalian diversification began about 175 million years ago in the Jurassic Period.

To help solve this mystery, scientists analyzed a remarkably well-preserved jaw from a haramiyid species known as Haramiyavia clemmenseni, discovered in Greenland in 1995.

“These fossils are extremely rare,” study lead author Zhe-Xi Luo, a paleontologist at the University of Chicago, told Live Science. “You have to go into the Arctic tundra and search for tiny little bits of fossils.”

The paleontologists theorized that Haramiyavia was a small creature, weighing from 50 to 70 grams, or about twice as much as an adult mouse.

“As the earliest known haramiyid, Haramiyavia is the key piece of evidence for inferences about the timeline of early mammalian evolution,” Luo said in a statement.

The researchers used high-resolution computed tomography (CT) scans to develop 3D computer models of the jaw that helped them investigate this specimen in unprecedented detail.

“With the CT scans, we were able to see every little piece of this fossil,” Luo said.

This high-tech analysis revealed many primitive structures in the haramiyid jaw, including a trough in the back of the jaw that would have been connected to a primitive middle ear, and a bony prominence on the hinge of the jawbone. These two features provide strong evidence that haramiyids are more primitive than true mammals. This theory is supported by the lack of these two jaw features in the multituberculates, a group of early mammals that prior research suggested was closely related to the haramiyids.

“This was clearly a dead branch of the mammal family tree, going off to the side,” Luo said, referring to the haramiyids.

The scientists also created virtual animations that showed how Haramiyaviateeth functioned. Their research showed that haramiyids possessed incisors for cutting and complex cheek teeth for grinding plant food, suggesting that they were omnivores or herbivores. In contrast, other early proto-mammalian groups had less complex teeth, which were adapted for eating insects or worms.

“They broke away from being insectivores and carnivores and invaded an herbivorous-eating niche, opening up a whole new world for themselves,” Luo said.

Plant-eating mammals did later evolve complex teeth similar to those of haramiyids, despite the fact that they were not direct descendants of haramiyids. This is a striking example of convergent evolution, a bit like how flapping wings evolved from arms in birds, pterosaurs and bats.

“This herbivory adaptation evolved many times,” Luo said.

Many questions remain about how haramiyids lived. “Now that we know their address on the evolutionary tree, we want to better understand how they went about their daily lives — for instance, we’d like to know how they moved about,” Luo said.

The scientists detailed their findings online Nov. 16 in the journal Proceedings of the National Academy of Sciences.

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Origins of human alcohol consumption revealed

alcohol1.jpg

File photo (GERMANY-BEER/ REUTERS/Michael Dalder)

Human ancestors may have begun evolving the knack for consuming alcohol about 10 million years ago, long before modern humans began brewing booze, researchers say.

The ability to break down alcohol likely helped human ancestors make the most out of rotting, fermented fruit that fell onto the forest floor, the researchers said. Therefore, knowing when this ability developed could help researchers figure out when these human ancestors began moving to life on the ground, as opposed to mostly in trees, as earlier human ancestors had lived.

“A lot of aspects about the modern human condition everything from back pain to ingesting too much salt, sugar and fat goes back to our evolutionary history,” said lead study author Matthew Carrigan, a paleogeneticist at Santa Fe College in Gainesville, Florida. “We wanted to understand more about the modern human condition with regards to ethanol,” he said, referring to the kind of alcohol found in rotting fruit and that’s also used in liquor and fuel.

To learn more about how human ancestors evolved the ability to break down alcohol, scientists focused on the genes that code for a group of digestive enzymes called the ADH4 family. ADH4 enzymes are found in the stomach, throat and tongue of primates, and are the first alcohol-metabolizing enzymes to encounter ethanol after it is imbibed.

The researchers investigated the ADH4 genes from 28 different mammals, including 17 primates. They collected the sequences of these genes from either genetic databanks or well-preserved tissue samples. [Holiday Drinking: How 8 Common Medications Interact with Alcohol]

The scientists looked at the family trees of these 28 species, to investigate how closely related they were and find out when their ancestors diverged. In total, they explored nearly 70 million years of primate evolution. The scientists then used this knowledge to investigate how the ADH4 genes evolved over time and what the ADH4 genes of their ancestors might have been like.

Then, Carrigan and his colleagues took the genes for ADH4 from these 28 species, as well as the ancestral genes they modeled, and plugged them into bacteria, which read the genes and manufactured the ADH4 enzymes. Next, they tested how well those enzymes broke down ethanol and other alcohols.

This method of using bacteria to read ancestral genes is “a new way to observe changes that happened a long time ago that didn’t fossilize into bones,” Carrigan said.

The results suggested there was a single genetic mutation 10 million years ago that endowed human ancestors with an enhanced ability to break down ethanol. “I remember seeing this huge difference in effects with this mutation and being really surprised,” Carrigan said.

The scientists noted that the timing of this mutation coincided with a shift to a terrestrial lifestyle. The ability to consume ethanol may have helped human ancestors dine on rotting, fermenting fruit that fell on the forest floor when other food was scarce.

“I suspect ethanol was a second-choice item,” Carrigan said. “If the ancestors of humans, chimps and gorillas had a choice between rotten and normal fruit, they would go for the normal fruit. Just because they were adapted to be able to ingest it doesn’t mean ethanol was their first choice, nor that they were perfectly adapted to metabolize it. They might have benefited from small quantities, but not to excessive consumption.”

In people today, drinking in moderation can have benefits, but drinking in excess can definitely cause health problems, experts agree. Scientists have suggested that problems people have with drinking, such as heart disease, liver disease, and mental health problems, result because humans have not evolved genes to sufficiently process ethanol. Similarly, humans have not evolved genes to handle large amounts of sugar, fat and salt, which, in turn, have given way to obesity, diabetes, high blood pressure and many other health problems.

One model for the evolution of alcohol consumption suggests that ethanol only entered the human diet after people began to store extra food, potentially after the advent of agriculture, and that humans subsequently developed ways to intentionally direct the fermentation of food about 9,000 years ago. Therefore, the theory goes, alcoholism as a disease resulted because the human genome has not had enough time to fully adapt to alcohol.

Another model suggests that human ancestors began consuming alcohol as early as 80 million years ago, when early primates occasionally ate rotting fermented fruit rich in ethanol. This model suggests that the attraction to alcohol started becoming a problem once modern humans began intentionally fermenting food because it generated far more ethanol than was normally found in nature. The new findings support this model.

In the future, Carrigan and his colleagues want to investigate what the ethanol content of fallen fruit might be, and find out whether apes, such as chimpanzees or gorillas, are willing to consume fermented fruit with varying levels of ethanol.

“We also want to look at other enzymes involved in alcohol metabolism, to see if they’re co-evolving with ADH4 at the same time,” Carrigan said.

The scientists detailed their findings online Dec. 1 in the journal Proceedings of the National Academy of Sciences.

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‘Pop-Up’ 3D structures can mimic brain circuits

pop-up-3d-structures

A 3D silicon microstructure. (J. Rogers, University of Illinois)

By mimicking children’s pop-up books, scientists can now make complex microscopic 3D shapes that model brain circuitry and blood vessels, researchers say.

These intricate structures, which could resemble tiny flowers and peacocks, may one day help scientists electronically control living tissue, the researchers added.

Naturally curved, thin and flexible 3D structures are common in biology; examples include the circuits of brain cells and networks of veins. Materials scientist John Rogers, at the University of Illinois at Urbana-Champaign, and his colleagues want to create similarly complex devices that can wrap around these biological structures, potentially supporting or improving their function. [5 Crazy Technologies That Are Revolutionizing Biotech]

“Our focus has been on the brain, heart and skin,” Rogers said.

Devices that mimic the complex structures found in nature are very difficult to manufacture on microscopic scales. But now, Rogers and his colleagues have developed a simple strategy for such manufacture that involves flat 2D structures that pop up into 3D shapes.

“The analogy would be children’s pop-up books,” Rogers told Live Science.

To manufacture these structures, the scientists fabricate 2D patterns of ribbons on stretched elastic silicone rubber. In experiments, the ribbons were as small as 100 nanometers wide, or about 1,000 times thinner than the average human hair, and could be made from a variety of materials, including silicon and nickel.

The 2D patterns are designed so that there are both strong and weak points of stickiness between the patterns and the silicone rubber they sit on. After the scientists fabricate the 2D designs, they release the tension on the silicone rubber. The weak points of stickiness break away, “and up pops a 3D structure,” study co-author Yonggang Huang, a professor of mechanical engineering at Northwestern University in Evanston, Illinois, said in a statement. “In just one shot, you get your structure.”

The researchers generated more than 40 different geometric designs, from single and multiple spirals and rings to spherical baskets, cubical boxes, peacocks, flowers, tents, tables and starfish. Scientists could even arrange patterns with multiple layers, a bit like multi-floor buildings.

This new pop-up technique has many advantages, the investigators said. The strategy is fast, inexpensive and can employ many different materials used in electronics today to build a wide variety of microscopic structures. Moreover, researchers can build many different structures at one time, and incorporate different materials into hybrid structures.

“We are excited about the fact that these simple ideas and schemes provide immediate paths to broad and previously inaccessible classes of 3D micro- and nano-structures in a way that is compatible with the highest-performance materials and processing techniques available,” Rogers said. “We feel that the findings have potential relevance to a wide range of microsystems technologies biomedical devices, optoelectronics, photovoltaics, 3D circuits, sensors and so on.”

The scientists said their pop-up assembly technique has many advantages over3D printers, which create 3D structures by depositing layers of material on top of one another. Although 3D printers are increasingly popular, they work slowly. In addition, it is difficult for 3D printers to build objects using more than one material, and it is nearly impossible for these printers to produce semiconductors or single crystalline metals, the researchers said.

Still, Rogers emphasized the team’s new strategy is complementary to 3D printing, and is not an attempt to replace that technique.

The scientists are currently using this pop-up assembly strategy to build electronic scaffolds that can monitor and control the growth of cells in lab experiments, Rogers said. “We are also using these ideas to form helical, springy metal interconnect coils and antennas for soft electronic devices designed to integrate with the human body,” he said.

The scientists detailed their findings online Jan. 8 in the journal Science.

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Dino, heal thyself: Giant beast had power to shrug off bone trauma

allosaurus-skeleton

Researchers bombarded a toe bone from a giant carnivorous dinosaur, Allosaurus fragilis (shown here), finding that the beast apparently had an amazing power to heal its broken bones.Phillip Manning.

A giant carnivorous dinosaur apparently possessed an enormous power to heal its broken bones, thanks to new findings revealed by powerful X-rays, researchers say.

The new findings suggest this ancient predator could shrug off massive trauma, revealing the dinosaur healed well like reptiles do than more poorly like birds do, which dinosaurs are more closely related to, scientists added.

Dinosaur bones sometimes include evidence they cracked and mended while the reptiles lived. Such findings can yield insights into how much violence dinosaurs experienced, and whether they healed differently than other animals.

Analyzing fossils for signs of healed fractures often involves slicing through them, damaging these rarities. Now scientists have used intense X-rays with beams brighter than 10 billion suns to illuminate breaks hidden within the bones of a 150-million-year-old predatory dinosaur.

[Paleo-Art: Dinosaurs Come to Life in Stunning Illustrations]

The researchers examined a toe bone from a giant carnivorous dinosaur,Allosaurus fragilis, excavated from Utah. They bombarded the fossil with X-rays from the Diamond Light Source in England and the Stanford Synchrotron Radiation Lightsource in California. Both light sources are synchrotrons, or particle accelerators that can generate powerful beams of light, which the investigators used to analyze the chemical nature of samples down to a resolution of 2 microns, or 1/50th the average diameter of a human hair.

There are subtle chemical differences between normal and healed bone tissue. The scientists discovered they could detect the “chemical ghosts” of ancient breaks.

“This is beyond recognizing a healed injury this is mapping the biological processes that enable that healing,” said study author Phillip Manning, a paleontologist and director of the Interdisciplinary Center for Ancient Life at the University of Manchester in England. “The ability to map the biological processes of healing allows great insight to the physiology and metabolism of animals. To extend this into the fossil record might provide new insight on many groups of vertebrates, not just dinosaurs.”

The researchers found this dinosaur could apparently shake off massive trauma, healing from injuries that would prove fatal to humans if not treated. Curiously, this fact suggests dinosaurs healed more effectively like reptiles such as crocodilians than less effectively like close dinosaur relatives such as birds, Manning told Live Science. One might speculate these differences are due in part to how birds typically possess hollow bones to lighten them for flight.

“This is the starting point in a new line of research that has a long way to go when comparing the chemistry of bone between species, both modern and extinct,” Manning said. “We are already looking at new techniques that might further expand our understanding of the growth, trauma and healing of bones in vertebrates.”

Manning and his colleagues detailed their findings online today (May 7) in the Journal of the Royal Society Interface.

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What we learned about human origins in 2013

What we learned about human origins in 2013

By Charles Q. Choi

Published December 30, 2013

LiveScience
  • dmanisi-human-skull-1

    The 1.8-million-year-old skull unearthed in Dmanisi, Georgia, suggests the earliest members of the Homo genus belonged to the same species, say scientists in a paper published Oct. 18, 2013 in the journal Science. (PHOTO COURTESY OF GEORGIAN NATIONAL MUSEUM)

The existence of a mysterious ancient human lineage and the possibility that the earliest humans were actually all one species were among the human-evolution-related discoveries of 2013. Other breakthroughs include the sequencing of the oldest human DNA yet.

Here’s a look at what scientists learned about humanity and human origins this year:

Mystery lineage
Recent analyses of fossil DNA have revealed that modern humans occasionally had sex and produced offspring not only with Neanderthals but also with Denisovans, a relatively newfound lineage whose genetic signature apparently extended from Siberia to the Pacific islands of Oceania.

This year, hints began emerging that another mystery human lineage was part of this genetic mix as well. Now, the first high-quality genome sequence from a Neanderthal has confirmed those suspicions.

These findings come from Denisova Cave in southern Siberia, where the first evidence of Denisovans was discovered in 2008. To learn more about the Denisovans, scientists examined DNA from a toe bone unearthed there in 2010.

The researchers found that the fossil belonged to a Neanderthal woman. Her DNA helped refine the human family tree, as it revealed that about 1.5 to 2.1 percent of the DNA of modern people outside Africa is Neanderthal in origin, whereas about 0.2 percent of DNA of mainland Asians and Native Americans is Denisovan in origin. [Top 10 Mysteries of the First Humans]

The scientists also discovered that the Denisovans interbred with an unknown human lineage, getting as much as 2.7 to 5.8 percent of their genomes from it. This newfound relative apparently split from the ancestors of all modern humans, Neanderthals and Denisovans between 4 million and 900,000 years ago, before these latter groups started diverging from each other. It’s possible that this mysterious lineage could even be Homo erectus, the earliest known undisputed predecessor of modern humans. However, there are no signs that this unknown group interbred with modern humans or Neanderthals.

Genetic analysis also revealed that the parents of this Neanderthal woman were closely related possibly half-siblings, or another close relative. (Inbreeding may have been common among early humans it remains uncertain as to whether it was some kind of cultural practice or whether it was unavoidable due to small community populations at the time.)

Were earliest humans all one species?
Modern humans, Homo sapiens, are the only living member of the human lineage, Homo, which is thought to have arisen in Africa about 2 million years ago at the beginning of the Ice Age. Many now-extinct human species were thought to once roam the planet, such as Homo habilis, which is suspected to be among the first stone-tool makers; the relatively larger-brained Homo rudolfensis; the relatively slenderHomo ergaster; and Homo erectus, the first to regularly keep the tools it made.

The level of variation seen in Homo fossils is typically used to define separate species. However, analysis of 1.8-million-year-old skulls excavated from the Republic of Georgia revealed the level of variation seen among those skulls was about the same as that seen among ancient African Homo fossils. As such, researchers suggest the earliest Homo fossils may not be multiple human species, but rather variants of a single lineage that emerged from Africa. In other words, instead of Africa once being home to multiple human species such asHomo erectusHomo habilisHomo ergaster and Homo rudolfensis, all of these specimens may actually simply be Homo erectus.

Oldest human DNA
The testing of the oldest known human DNA added more evidence that human evolution was complex.

The genetic material, some 400,000 years old, came from a human thighbone unearthed in the Sima de los Huesos, or “Pit of Bones,” an underground cave in northern Spain. Until now, the previous oldest known human DNA had come from a 100,000-year-old Neanderthal from a Belgian cave.

The fossils unearthed at the site resembled those of Neanderthals, so researchers expected the ancient DNA they analyzed to be Neanderthal as well. Surprisingly, the DNA revealed that this fossil’s closest known relatives were not Neanderthals but Denisovans. This finding is strange, scientists said, because studies to date currently suggest the Denisovans lived in eastern Asia, not in western Europe, where this fossil was uncovered. One possible explanation is that a currently unknown human lineage brought Denisovan-like DNA into the Pit of Bones region, and possibly also to the Denisovans in Asia.

Evolution of tool use
The capability to make and use complex tools is a critical trait distinguishing modern humans from all other species alive today. Now, scientists have found an ancient hand-bone fossil that reveals that the modern human ability to make and use complex tools may have originated far earlier than previously thought.

A key anatomical feature of the modern human hand is the third metacarpal, a bone in the palm that connects the middle finger to the wrist. A little projection of bone known as a styloid process in this bone helps the thumb and fingers apply greater amounts of pressure to the wrist and palm. Researchers had thought the styloid process was a relatively recent feature, perhaps evolving close to the origin of modern humans. However, scientists have discovered a 1.4-million-year-old fossil that possesses this vital anatomical feature, meaning it existed more than 500,000 years earlier than it was previously known to have existed and was perhaps fundamental to the evolution of the whole genus Homo, not just modern humans.

This hand bone may not be the only key trait for tool use that evolved near the origin of the human lineage. Humans are the only species that can throw with great speed and precision, and scientists found this ability first evolved nearly 2 million years ago with anatomical changes to the shoulder, arm and torso. This advance likely boosted the hunting prowess of now-extinct human ancestors, helping them effectively and safely kill big game.

Neanderthal discoveries
In 2013, researchers also made important discoveries about Neanderthals, modern humans’ closest extinct relatives. For instance, analysis of a Neanderthal tomb in France suggests that, like modern humans, Neanderthals may have intentionally buried their dead. The new findings are further evidence that Neanderthals might have possessed complex forms of thought, enough for special treatment of the dead.

In addition, a cache of Neanderthal fossils discovered in a cave in Greece suggests the area may have been a key crossroad for ancient humans. The age of these fossils suggests Neanderthals and other humans may have had the opportunity to cross paths there, and even interact, the researchers added.

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Human hand fossil turns back clock 500,000 years on complex tool use

Human hand fossil turns back clock 500,000 years on complex tool use

By Charles Q. Choi

Published December 17, 2013

LiveScience
  • human-hand-fossil

The discovery of a 1.4-million-year-old hand-bone fossil reveals that the modern human ability to make and use complex tools may have originated far earlier than scientists previously thought, researchers say.

A critical trait that distinguishes modern humans from all other species alive today is the ability to make complex tools. It’s not just the extraordinarily powerful human brain, but also the human hand, that gives humans this unique ability. In contrast, apes humans’ closest living relatives lack a powerful and precise enough grip to create and use complex tools effectively.

A key anatomical feature of the modern human hand is the third metacarpal, a bone in the palm that connects the middle finger to the wrist.

“There’s a little projection of bone in the third metacarpal known as a “styloid process” that we need for tools,” said study lead author Carol Ward, an anatomist and paleoanthropologist at the University of Missouri.”This tiny bit of bone in the palm of the hand helps the metacarpal lock into the wrist, helping the thumb and fingers apply greater amounts of pressure to the wrist and palm. It’s part of a whole complex of features that allows us the dexterity and strength to make and use complex tools.” [In Images: The Oddities of Human Anatomy]

Until now, this styloid process was found only in modern humans, Neanderthals and other archaic humans. Scientists were unsure when this bone first appeared during the course of human evolution. (The human lineage, the genus Homo, first evolved about 2.5 million years ago in Africa.)

“We had thought the modern human hand was something relatively recent, maybe something that appeared as a recent addition near the origin of our species,” Ward told LiveScience.

Now, researchers have discovered a fossil almost 1.5 million years old that possesses this vital anatomical feature, meaning it existed more than 500,000 years earlier than it was previously known to have existed.

“This suggests this feature might be fundamental to the origin of the genus Homo,” Ward said.

The scientists discovered a third metacarpal bone in northern Kenya, west of Lake Turkana. The fossil was found near the sites where the earliest Acheulean tools named for St. Acheul in France where tools from this culture were first discovered in 1847 were unearthed. The Acheulean artifacts were the first known complex stone tools, rough hand axes and cleavers that first appeared some 1.8 million years ago.

“It’s an arid badlands desert area now,” Ward said. “There’s not much vegetation to cover up fossils there’s cobble and rock everywhere, and we try and find fossils by going out and looking under all that cobble and rock on the surface.”

The hand-bone fossil is about 1.42 million years old. The researchers suspect it belonged to the extinct human species Homo erectus, the earliest undisputed predecessor of modern humans.

“Back then, this area was an open woodland area much more lush than today, probably with some trees and some areas of grassland,” Ward said. “The fossil was found near a winding river, which often deposits things like fossils.”

By revealing the early human lineage had a modern handlike anatomy, the fossil “suggests this feature may have [been] a pre-adaptation that helped set the stage for all the technology that came later,” Ward said.

Intriguingly, “at this time, in addition to early members of Homo, there were some late-surviving members of Australopithecus still around close relatives of humans that don’t seem to have this adaptation,” Ward said. “This raises the question of how important our hands were in the success of our lineage and the extinction of their lineage (Australopithecus).”

The researchers now want to find older hand bones “to see when this feature evolved,” Ward said. “We want to get closer to 2 million years ago to find out when this transition to modern hand anatomy took place.”

Ward and her colleagues detailed their findings online Dec. 16 in the journal Proceedings of the National Academy of Sciences.

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Neanderthal woman’s genome reveals unknown human lineage

NOTE:  For those of you newer to my blog site, you might not know my viewpoint on God, the Universe and Science.  You see, I am a right-wing Christian fundamentalist – but nothing like what you think that really means.  I believe in God and the Bible, but I also have three science degrees, love all people, have a 168 IQ and write magazine columns on astro-physics.  My belief in God is not based on blind faith, although for many that is true.  For others, their non-belief comes to them the same way, through blind acceptance and not a true search for truth.

I believe that science and creation theory are the same.  If there is no God, it just happened.  If there is a God, then he is a being far beyond our comprehension who created the original time/space anomaly that popped existence as we know it today into being.  With my background in statistics, I believe it is far more possible that the intricacies we view at all levels imply a design, which implies a designer.  However, there is no proving that.  One can equally believe it “just happened” and is not the result of a design.

So, I don’t believe in a bearded man in the clouds.  I believe in someone beyond our comprehension, who is therefore, by definition, and advanced alien being.  My theory, which is only my own and not shared by many Christians, is that there are multiple aliens who have experimented on mankind for a long, long time.  I think there were advanced civilizations that have come and gone and been long forgotten and lost to us.

So, how do I explain my lack of belief in the Evolution Theory?  First, I absolutely believe things evolve.  My only disagreement is that I believe we evolved due to outside influences, and that we were created in God’s image.  By His image, I believe we have a physical, temporary life, but we have an immortal essence.  For whatever reason, this existence is our testing zone.  The ones who can show love and compassion for each other will be transformed after to death into a reality we have no comprehension of at all.  In fact, “we shall be transformed in an instant” and there “will be no male or female, but spirits of light.”

For this reason, I find it very possible that ancient Sumerian myths of fish gods teaching them, the ancient alien theorists, the Greek gods, ancient writing and creatures, do in fact have basis in external manipulation on this planet.  As we find more and more about early man, we are finding it was not a chain of evolution, but pockets of similar humans living in different spots, sometimes interbreeding.  Adam and Eve were not the first humans in the Bible.  In fact, when Cain was driven out, he was afraid others would kill him, so a mark was put on him, and he took another woman for his wife.  The Bible makes references to other tries at children of God and earlier extinctions.

I don’t try to convince you of any of this.  All I ask is that you keep an open mind when I post about early man, new archaeology, and other finds.  I really don’t think any of us have much of a clue what went on past 5,000 years ago.  Including me.

– Michael Bradley

Neanderthal woman’s genome reveals unknown human lineage

By Charles Q. Choi

Published December 19, 2013

LiveScience
  • neanderthal-illustration

    Neanderthals were once the closest living relatives of modern humans, dwelling across a vast area ranging from Europe to the Middle East to western Asia. This ancient lineage of humans went extinct about 40,000 years ago, about the same time mo(MAURO CUTRONA)

The existence of a mysterious ancient human lineage and the genetic changes that separate modern humans from their closest extinct relatives are among the many secrets now revealed in the first high-quality genome sequence from a Neanderthal woman, researchers say.

The Neanderthal woman whose toe bone was sequenced also reveals inbreeding may have been common among her recent ancestors, as her parents were closely related, possibly half-siblings or another near relation.

Although modern humans are the world’s only surviving human lineage, others also once lived on Earth. These included Neanderthals, the closest extinct relatives of modern humans, and the relatively newfound Denisovans, whose genetic footprint apparently extended from Siberia to the Pacific islands of Oceania. Both Neanderthals and Denisovans descended from a group that diverged from the ancestors of all modern humans. [See Photos of Neanderthal Bone & Denisovan Fossils]

The first signs of Denisovans came from a finger bone and a molar tooth discovered in Denisova Cave in southern Siberia in 2008. To learn more about Denisovans, scientists examined a woman’s toe bone, which was unearthed in the cave in 2010 and showed physical features resembling those of both Neanderthals and modern humans. The fossil is thought to be about 50,000 years old, and slightly older than previously analyzed Denisovan fossils.

Human interbreeding
The scientists focused mostly on the fossil’s nuclear DNA, the genetic material from the chromosomes in the nucleus of the cell that a person receives from both their mother and father. They also examined the genome of this fossil’s mitochondria the powerhouses of the cell, which possess their own DNA and get passed down solely from the mother.

The investigators completely sequenced the fossil’s nuclear DNA, with each position (or nucleotide) sequenced an average of 50 times. This makes the sequence’s quality at least as high as that of genomes sequenced from present-day people.

The genetic analysis revealed the toe bone belonged to a Neanderthal. When compared with other Neanderthal mitochondrial DNA samples, this newfound fossil’s closest known relatives are Neanderthals found in Mezmaiskaya Cave in the Caucasus Mountains about 2,100 miles away.

These findings helped the scientists refine the human family tree, further confirming that different human lineages interbred. They estimated about 1.5 to 2.1 percent of DNA of people outside Africa are Neanderthal in origin, while about 0.2 percent of DNA of mainland Asians and Native Americans is Denisovan in origin.

“Admixture seems to be common among human groups,” said study lead author Kay Prfer, a computational geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

Intriguingly, the scientists discovered that apparently Denisovans interbred with an unknown human lineage, getting as much as 2.7 to 5.8 percent of their genomes from it. This mystery relative apparently split from the ancestors of all modern humans, Neanderthals and Denisovans between 900,000 years and 4 million years ago, before these latter groups started diverging from each other.

This enigmatic lineage could even potentially be Homo erectus, the earliest undisputed predecessor of modern humans. There are no signs this unknown group interbred with modern humans or Neanderthals, Prferadded. [The 10 Biggest Mysteries of the First Humans]

“Some unknown archaic DNA might have caught a ride through time by living on in Denisovans until we dug the individual up and sequenced it,” Prfertold LiveScience. “It opens up the prospect to study the sequence of an archaic (human lineage) that might be out of reach for DNA sequencing.”

Interbreeding took place between Neanderthals and Denisovans as well. These new findings suggest at least 0.5 percent of the Denisovan genome came from Neanderthals. However, nothing of the Denisovan genome has been detected in Neanderthals so far.

In addition, “the age of the Neanderthals and Denisovans we sequenced also doesn’t allow us to say whether any gene flow from modern humans to Neanderthals or Denisovans happened,” Prfer said. The Neanderthals and Denisovans that researchers have sequenced the DNA of to date “probably lived at a time when no modern humans were around,” he explained.

Modern humans’ distinguishing features
It remains uncertain when modern humans, Neanderthals and Denisovans diverged from one another. The researchers currently estimate modern humans split from the common ancestors of all Neanderthals and Denisovans between 550,000 and 765,000 years ago, and Neanderthals and Denisovans diverged from each other between 381,000 and 473,000 years ago.

Genetic analysis revealed the parents of the woman whose toe bone they analyzed were closely related possibly half-siblings, or an uncle and niece, or an aunt and nephew, or a grandfather and granddaughter, or a grandmother and grandson. Inbreeding among close relatives was apparently common among the woman’s recent ancestors. It remains uncertain as to whether inbreeding was some kind of cultural practice among these Neanderthals or whether it was unavoidable due to how few Neanderthals apparently lived in this area, Prfer said.

By comparing modern human, Neanderthal and Denisovan genomes, the researchers identified more than 31,000 genetic changes that distinguish modern humans from Neanderthals and Denisovans. These changes may be linked with the survival and success of modern humans a number have to do with brain development.

“If one speculates that we modern humans carry some genetic changes that enabled us to develop technology to the degree we did and settle in nearly all habitable areas on the planet, then these must be among those changes,” Prfer said. “It is hard to say what exactly these changes do, if anything, and it will take the next few years to find out whether hidden among all these changes are some that helped us modern humans to develop sophisticated technology and settle all over the planet.”

Prfer and his colleagues detailed their findings in the Dec. 19 issue of the journal Nature.

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