Tag Archives: evolution

New Hominid Ancestor Lived 3.7 Million Years Ago

Deep in Ethiopia’s Awash Valley about four decades ago, paleontologists came very close to understanding the origin of modern humans when they unearthed Australopithecus afarensis, better known as Lucy, an upright walking ape that lived about 3.2 million years ago, one of our distant ancestors. Now we know that Lucy wasn’t alone – sharing the savannah with another ape-like creature that scientists refer to as “Little Foot,” suggesting a rich evolutionary diversity throughout much of Africa at the time.

The date of the fossil is important for another reason – it may give us a closer approximation to when modern day humans first began to appear. Currently, Australopithecines are ranking high among the species believed to be our direct ancestors, living in Africa between 2.9 million and 4.1 million years ago. The exact lineage from which we came, Homo, dates back to approximately two million years ago.

Although the Australopithecus afarensis thrived in the grasslands of eastern Africa, another australopithecine nicknamed Little Foot, due to the diminutive nature of the bones, lived in southern Africa. Discovered about 20 years ago by paleoanthropologist Ronald Clarke from the University of the Witwatersrand in South Africa, Little Foot apparently fell down a narrow shaft in the Sterkfontein Caves. This left behind a nearly complete skeleton that could yield key insights on human evolution.

So what sort of australopithecine was Little Foot? There are about five different varieties known, and also the sub tribes of hominins Paranthropus and Ardipithecus which had comparable brain sizes and walked on two legs. A number of scientists think that Little Foot likely belonged to the genus Australopithecus africanus, which differed from Lucy in that it had a rounder skull used to contain a slightly larger brain and smaller teeth than Lucy or much else of Australopithecus afarensis. Now Clarke and his colleagues have proposed the idea that perhaps Little Foot may have been another type of australopithecine – the Australopithecus prometheus, which was characterized by a longer and flatter face as well as larger cheek teeth than the Australopithecus africanus.

“It was impossible to fit Little Foot into the human family tree with any certainty because ever since its discovery, the age of Little Foot has been debated,” according to the study’s lead author Darryl Granger, who is a geochronologist at Purdue University of West Lafayette, Indiana. If the researchers are able to determine successfully when Little Foot’s family tree first came into being, they might then be able to make a more accurate distinction of when Australopithecus first diverged, as well as which region of Africa the Homo genus first originated in.

While most paleoanthropologists agree that the first hominins, as well as all of the modern human race, have ancestral roots in Africa, it is difficult to pinpoint a precise starting point, since a rapidly changing climate drove them across the continent and gradually towards the Middle East and European mainland.

The evidence discovered by Granger and his colleagues has suggested that Little Foot lived at approximately the same time as Lucy, but the current fossilized remains are not yet sufficient enough to determine what species it belonged to.

“The most important implication from dating Little Foot is that we now know that australopithecines were in South Africa early in their evolution,” Granger told Live Science. “This implies an evolutionary connection between South Africa and East Africa prior to the age of Little Foot, and with enough time for the australopithecine species to diverge.”

This proposes another issue that many have not considered, however – other australopithecines — and, eventually, humans, such as Neanderthals and Homo Sapiens, “did not all have to have derived from Australopithecus afarensis,” Clarke told Live Science. “There could well have been many species of Australopithecusextending over a much wider area of Africa.”

The researchers made their first attempt at determining the age of Little Foot a little over a decade ago. Their result was an age of around four million years, which according to Granger, would rank Little Foot among the oldest of the australopithecines. Despite the fact that they looked a lot more like apes than humans (our closest living relative the chimpanzee quickly comes to mind), Australopithecines did show some signs of being human – the fossil record shows they cared for their children much like modern humans, and they may have had a sense of aesthetic. Some of their dwellings contained stones that resembled faces, collected from nearby valleys.

You might wonder how they can date materials discovered within a cave, which can prove to be another frustrating problem for archaeologists. Besides being able to determine if they’re from the same era as the remains found within the cave, there is also the problem of erosion that could cause unearthed materials to fill a cave along with water currents and sediments, something that could easily throw off most types of analysis. Such mineral rich runoff is known as flowstones when found in caves. The initial step taken by archaeologists was to date this material, which revealed an age of 2.2 million years old. “I was disappointed, but I could see nothing wrong with their ages,” Granger recalled.

A recent study suggested the flaw with this method – as the flowstones formed at a different time than the rock layer containing the fossils. For their newest analysis, Granger and colleagues were able to determine the age of the fossils with by analyzing the aluminum and beryllium isotopes in quartz found in the same layer, a technique known as surface exposure dating, which can give dates on mineral materials that are up to 30 million years old.

The researchers came across something else surprising – the earliest stone tools that they discovered within the same cave only date back about 2.2 million years ago. This gives them an age similar to the early stone tools discovered throughout eastern and southern Africa, indicating that there must have been some degree of interaction between their later descendants. “This implies a connection between South African and East African hominids that occurred soon after the appearance of stone tools,” Granger said.

The researchers hope that their new dating method will be used by other archaeological sites across the globe. will “There should be a thorough study to explore the strengths and weaknesses of the method,” Granger said.

The findings made by Granger, Clarke and their research team were documented and published in the April 2 issue of the journal Nature.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

Ancient elixirs to fight modern superbacteria

The Middle Ages has long suffered an unfortunate reputation as being a dark period of violence and superstition. It was a time when disease ran rampant – particularly the infamous Black Death, which may have wiped out as much as one-third of Europe in the 14th century as it made its way from China’s Silk Road. Western medicine seemed helpless against the waves of plague – something that would again ravage London in the 17th century, and is now attributed to three strains of plague transmitted by the bacteria Yersinia pestis.

While medieval physicians didn’t know about microbes, however, it doesn’t mean that their medicine was entirely useless. While there may not have been many ancient elixirs effective against plague, one remedy might actually be an effective weapon against a very modern type of plague: antibiotic-resistant superbacteria.

Researchers at the University of Nottingham in Great Britain successfully replicated a medieval potion and subsequently tested it against one strand of bacteria that is notoriously aggressive and prevalent in hospitals: staphylococcus aureus, more commonly known as MRSA. The remedy is over a millennia old and was first developed by populations of Anglo-Saxon that occupied Britain in the early Middle Ages.

If the name sounds familiar – that’s because it is – the town just a breath away from the legendary Sherwood Forest, which now harbors an Institute for Medieval Research. Some historians leafed through a 1,000 year old manuscript known as “Bald’s Leechbook,” where they found a remedy for eye infection – perhaps something that Robin Hood’s band of merrymen would be prone to – scratched corneas after an armed skirmish with Nottingham’s sheriff.

The infection would typically be treated by an herbalist, mixing the concoction in a brass vessel, along with a remedy of bile, mixed in the cow’s stomach, and some freshly picked Allium that grows in the forest, a bulb closely related to garlic.

Viking studies professor Christina Lee first found the potion and went about translating the recipe from Old English. While herbalists had hardly the same training as today’s medical doctors, they had to at least have some method for determining the right treatment for different types of infection. It must have been a bit like working in the dark, too, as they had a few centuries to go before germ theory of disease would be discovered.

To recreate the salve, she turned to chemists working at the university’s Center for Biomolecular Sciences.

It might have seemed like an unusual request, but little did Lee know that it would be a crucial step at addressing a growing concern. Antibiotics are often specific to one strain of pathogens, and dependent on entire generations of bacteria being wiped out. However, bacteria replicate at a rapid pace – producing several generations in just a matter of 24 hours. If one bacterial cell develops a tolerance for antibiotics, it can swiftly pass this along through a primitive evolutionary process known as horizontal gene transfer, eventually producing a generation of superbacteria. In hospitals, where many antibiotics are administered regularly, the environment for superbacteria is more inviting.

Lee’s investigation might actually have opened the doors to a new way of approaching the problem, going after antimicrobial agents that are found in nature, something that caught the attention of microbiologist Freya Harrison. In her lab, the chemists followed the recipe with precision, yielding four individual batches with fresh ingredients. They even used the medieval methods for cultivating it, with a brass sheet as their brewing container, where they poured the distilled water.

They then used lab conditions to set off the growth of a strain of Staphylococcus aureus bacteria, which had grown resistant to the standard drug Methicillin, each grown in a small piece of collagen. The impact of the salve was astounding: roughly only one in 1,000 bacterial cells survived.

Harrison said that she was “absolutely blown away” by the power of this antique concoction, something she initially suspected would have a slight antibacterial effect. Some ingredients of the salve – namely copper and bile salts showed some lethal effect on the bacteria in the lab. Plants in the garlic family have also been known for producing chemicals that will intercept the ability of healthy bacteria to damage tissue that had been infected – a property that has made garlic cloves a time-honored cold remedy.

There’s something to say about the whole being greater than the sum of its parts, however. When they combined all their ingredients, under medieval conditions, they found some even more exciting discoveries under the microscope. The eye salve acted more aggressively than the control substance they applied to another set of bacteria, with adhesive particles that were able to break through the bacteria’s sticky coating, tearing apart colonies of mature bacteria that showed little reaction to antibiotic treatments.

So potent was the concoction developed by Harrison’s research team that they later diluted the salve, seeing how much dose was needed to be effective. Even in situations where populations of S. aureus survived, communication between bacteria in the colony was disrupted – perhaps the most intriguing aspect of the salve. Without any cross-talk between the cells, the genes that promote antibiotic resistance could not be signaled – an important and organic way to attacking bacterial infections.

This new and unlikely coalition between historians – especially in the very specialized branch of medieval medicine – and microbiologists led to the development of a new program called AncientBiotics at Nottingham, where researchers are seeking funding to further explore this new parallel between the sciences and humanities.

“We know that MRSA-infected wounds are exceptionally difficult to treat in people and in mouse models,” said Kendra Rumbaugh, who performed the testing of Bald’s remedy on MRSA-infected skin wounds in mice. “We have not tested a single antibiotic or experimental therapeutic that is completely effective,” added Rumbaugh, a professor of surgery at Texas Tech University’s School of Medicine. But she said the ancient remedy was at least as effective – “if not better than the conventional antibiotics we used.”

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

What a Prehistoric Whale Skull Can Tell Us About the Birth of Humanity

Paleontologists are inching closer to the exact spot where modern day Homo sapiens first originated, and they found help through a rather unlikely clue. The fossilized skull of a whale that lived 17 million years ago is drawing them to humanity’s origins in East Africa. Here’s how:

The whale, classified as Ziphiidae, existed at a time when warm climates brought the East African plateau considerably lower than it is today. Unlike the dry grasslands it is today, this region was then hidden under dense foliage, according to the researchers. At some point it lifted far above the sea, pushing away much of the moist winds that these jungles were dependent upon – drying the land into a savannah. For scientists, it’s really been a question of when this separation between the plateau and the Indian Ocean took place.

Our distant ancestors may have swung from trees in the East African jungles, but as the trees died out in favor of grasses, our ancestors began the transition to walking upright on two legs, suggests the new research.

“It’s more or less the story about the bipedalism,” said study researcher Henry Wichura, a postdoctoral geoscience student at University of Potsdam in Germany.

The discovery of a skull belonging to a beaked whale, ziphiidae, buried in the rock layers has now allowed scientists to pinpoint the dates when the plateau began rising – sometime in the Pliocene – between approximately 17 million and 13.5 million years ago.

The whale skull was first discovered over 50 years ago – found by fossil hunters back in 1964 is one of rediscovery. Researchers originally found the fossil in 1964, but no studies were conducted on it for another decade. Then, the skull was misplaced, hidden in a museum archive at Harvard University until 2011. Surprisingly, it was discovered in the former office of the legendary paleontologist and science educator, Stephen Jay Gould. According to the study, it was placed there for safe keeping when the school’s archives were undergoing renovations.

The skull’s provenance is a bit more important than its discoverers first imagined. It is the oldest known fossil of a beaked whale, a rather puzzling discovery if you consider that these animals are actually deep sea divers. The fossil was uncovered 460 miles (740 kilometers) inland from the modern East African coast, and at 2,100 feet above sea level.

When it was alive, Wichura’s beaked whale grew to be 23-foot-long (7 m), swimming in the Indian Ocean. One day, however, he accidentally swam into a river towards present-day Kenya, where he eventually became trapped before his death.

“We came to the idea that it used a large river system, because the whale had been found in lake sediments which are [mixed with] river sediments,” Wichura said. “So we can say that it died in a kind of river-lake environment.”

The story might sound strange – a whale in a riverbed, but crazier things have happened. There are five known species of dolphin who prefer freshwater including the tucuxi, a close relative of marine dolphins that is found exclusively in the Amazon River basin. A sixth species recently became extinct. Back in 2006, a whale got stranded in the Thames River outside London, and killer whales have been found in the Columbia River near the Pacific Northwest. With the rapidly changing sea levels, incidents of this nature may have been more common.

In order to determine the depth of the prehistoric river basin, scientists took the grade of the steepest river out of the area’s case reports, applying its relative depth to the area. Were this 17 million year old river to rise 2.5 inches per mile from the coast, then the East African plateau would be somewhere between 79 feet and 121 feet high when the whale became stranded and died. They kept the difference in height as a variable – allowing that the whale may have chosen several different routes to swim along when entering the river.

Because the plateau is approximately 2,034 feet (620 m) high, the northern part of this plateau was lifted by almost 1,925 feet (590 m) within the last 17 million years.

Somewhere around 13.5 million years ago, Wichura learned that one portion of this land mass had already begun uplifting, giving the researchers a reasonable window into when the uplift started. The researchers were even able to attribute the cause of the uplift – mantle plumes – in which heated material is released from an underwater volcano from the Earth’s mantle and presses against its crust.

Had they not rediscovered the forgotten skull, this dating would have been considerably difficult.

“With the whale, everything started,” Wichura said to Live Science.

The study is a reminder to fossil hunters – both professional and amateur alike – that very often, the precise location of a fossil can sometimes be just as valuable – if not more – than the fossil itself, when it comes to understanding the prehistoric world in full context. The discovery of a single species is hardly significant on its own, but its place in time can reveal information about an entire extinct ecosystem, or even the history of a landscape that was once very different.

“Even single specimens of organisms tell us a great deal about the history of the Earth, and they sometimes appear in surprising cases,” Brown said. “This is one such case.”

This study was published on March 16 in the journal Proceedings of the National Academy of Sciences.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

Neanderthals Had Taste In Jewelry Too

Yet another discovery has been brought into the growing pile of evidence that suggests Neanderthals were not quite the savage, hairy monsters we often portray them as being. Recently the fossil evidence has shown that they were attentive parents, that they had an appreciation of art – creating cave paintings of their own, and that they held elaborate burials for their dead, but a new study elaborates a bit further on their personal tastes. According to a paper published today in PLOS ONE, the Neanderthal hominids may have developed their own jewelry – necklaces fashioned from eagle talons, that until recently were attributed to modern humans.

They disappeared some 39,000 years ago, shortly after modern humans began to enter Europe – for reasons that are not quite known. For some time before their extinction, the species are believed to have interbred, and perhaps they did not so much die out as become assimilated with homo sapiens. Our DNA is 99.7% identical to theirs, and modern humans who aren’t of African descent share about 2.5% of DNA with Neanderthals. Although this lineage has recently fallen into dispute, both Neanderthals and modern humans did originate in Africa, and may have shared a common ancestor. Not only did they craft jewelry, but their hunting skills may have rivaled those of modern humans as well. In order to craft the talon necklaces which seem like a necessary ingredient in most movies featuring prehistoric cavemen – they may have also been able to fashion traps to catch more than one eagle – at that time the sky’s apex predator.

The evidence came not from a recent archaeological dig, but rather through examining some old articles from a museum collection. (as so much evidence does) from the bowels of a museum collection. At the beginning of the 20th century, Croatian paleontologist Dragutin Gorjanović-Kramberger lead an excavation of a site near the Croatian village of Krapina, which was filled with Ice Age human and animal remains. While you may have never seen Gorjanović-Kramberger’s name in print before, during his career, he used newly invented X-ray machines to look at inner bone structures from his finds and he even developed a way to determine the ages of the skeletons he found, through analyzing their fluorine content, nearly half a century before carbon dating came into existence. The site he uncovered held almost a thousand human bones, the bones of several thousand animals, several thousand animal bones, alongside at least a thousand tools, all of which dated between 120,000 to 130,000 years ago. As a result, the town is now home to a large museum dedicated specifically to Neanderthal culture and evolution.

Like most modern paleontologists, Gorjanovic-Kramberger kept a detailed record of where each skeleton was found, but when it came to discovering the necklaces, he overlooked something rather obvious.

“He found these eagle talons and sent them to a bird specialist in Budapest,” said David Frayer of the University of Kansas, one of the new study’s researchers. “But ironically, even though he was the first person to identify cut marks on human bones, he missed these really obvious signs of cut marks and manipulation on the eagle talons.”

The bird specialist in Budapest also paid little attention to the talons as did the museum curators who kept the specimens stored in their collection for well over a century.

It was not until late 2013, when one of Frayer’s colleagues became curator of the Croatian Natural History Museum and gave the talons a second look. She gave him a call after she suspected that the markings had been made by the Neanderthals they were buried with.

“When I saw them, my jaw dropped,” he said. “The talons were so complete and so beautiful, and the cut marks were so obvious.”

The single most important detail is the age of the necklaces. They are 120,000 or 130,000 years old, when Croatia was occupied solely by the Neanderthals.

Researchers have in the past suspected that Neanderthals did craft the necklaces, but may have learned their trade from what were much more sophisticated homo sapiens. The only prototypes they had for this claim, were more modern necklaces found in France, dating to about 40,000 years ago.

“People often argue that Neanderthals were mimicking modern humans instead of coming up with ornamental things on their own,” Frayer said. “In this case, there’s no doubt: There were only Neanderthals there, and only Neanderthal tools.”

The patterns of wear of the talons have led Frayer and his colleagues to believe that the claws had been strung together and were worn as necklaces. Exposure to sweat as well as other bodily fluids led to a distinct type of polishing which is often found on shell bead necklaces made in the same way.

Eagles would be rare in the mountainous terrain where the Neanderthals lived, and were also highly aggressive, two aspects indicating that these Neanderthals were highly skilled when it came to hunting.

“There are talons from three or four different eagles here, and that represents a lot of planning and skill,” he said. “They’re big birds, and they’re vicious when caught.”

These were not run-of-the-mill prey – they were targets that some of the braver Neanderthals deliberately hunted. It took about three or four birds to make one necklace. Even the decision to use eagle talons as an ornament — if it really was intended for that — may also suggest that the Neanderthals had capacity for abstract thinking.

“When you catch the most powerful aerial predator in your environment and wear it around your neck, that suggests some kind of attempt to get its power,” he said.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

Evolution Brought Kindness Before Intelligence

All too often we imagine our hominid ancestors as hairy and primitive cavemen, living under the law of club and fang – unruly monsters that were more primate than human. The evidence, however, is painting a much different picture. Not only were other species of humans like the Neanderthals and Cro-Magnons capable of crafting tools and speaking languages, but human evolution in general likely brought about compassion and kindness some time before producing the intelligent beings of today.

Throughout history, we’ve thought of ourselves as the products of an evolutionary process grounded in intellect – only the brightest and the strongest spawned descendants, with each successive generation better than the last, the eventual outcome of lifeforms that became gradually more complex. However, according to a new study led by researcher Penny Spikins, from York University, this isn’t an entirely accurate assessment.

According to Spikins, there were at least three groups of the earliest human ancestors that exhibited altruistic behavior, developing some time before early humans showed evidence of intelligence and speech, concepts that are only about 150,000 years old.

“Human evolution is usually depicted as driven by intelligence, with empathy and deeper emotions following,” Spikins said. “However, the evidence suggests it happened the other way round. Evolution made us sociable, living in groups and looking after one another, even before we had language. Our success since then, including the evolution of intelligence, all sprang from that.”

Australopithecines, the species of ape to which Lucy belonged, were the first of our ancestors to walk upright, and lived in South Africa some three million years ago.

They had brains about one third the size of our own and were sometimes described by anthropologists as “killer apes” – a name that conjures up that scene from the beginning of 2001: A Space Odyssey. Spikins bristles at the term, reminding us of the Makapansgat pebble, found inside an African cave back in 1925 – a small stone shaped like a face that an Australopithecine did not carve, but collected and kept in its dwelling:

“What is remarkable is that this pebble was carried several miles back to its cave by an australopithecine. Did it remind them of a baby? It is impossible to tell for sure but this is not the only tantalising sign of something perhaps approaching tenderness.”

Another 1.5 million years after Lucy, and there is archaeological evidence that our close relative Homo ergaster lived in tribes that took care of their sick. There is also the Homo heidelbergensis, which lived about 450,000 years ago, and is thought to have raised disabled children to maturity.

“[Evidence suggests] early humans’ survival would have depend­ed on co-operation,” she said, considering the difficulty that they would have had hunting alone or evading predators. “Aggres­sive or selfish behaviour would have been very risky.”

Spikins published her research in the new book How Compassion Made Us Human. Another piece of her evidence is a 250,000-year-old axe which was decorated with a fossilized scallop – already, humans seemed to have developed their own sense of aesthetics and beauty that they recognized in nature well before they began cave paintings of their own.

“A uniquely human feeling lies behind both the creation of such finely crafted tools and caring for the vulnerable. It suggests early humans, from two million years ago, were emotionally similar to us.”

“Compassion is perhaps the most fundamental human emotion,” she added, but hardly unique to modern homo sapiens as we might imagine. “It binds us together and can inspire us but it is also fragile and elusive. This apparent fragility makes addressing the evidence for the development of compassion in our most ancient ancestors a unique challenge, yet the archaeological record has an important story to tell about the prehistory of compassion.” Far from clouding our judgment, it made building social networks possible in a dangerous and unpredictable world.

“We have traditionally paid a lot of attention to how early humans thought about each other, but it may well be time to pay rather more attention to whether or not they ‘cared’.”

Spikins was previously involved with research on Neanderthals, published in the Oxford Journal of Archaeology.

While she does not deny that the mountains of the Neander Valley was a harsh climates to grow up in during the Ice Age, with geography that often led to isolation, the small families of Neanderthals were actually fairly close to each other. They buried their dead and their children played games which developed the skills they would later use to function as members of the tribe. Not only did parents care for sick or injured children, but child graves were marked with much more distinction than those of tribal elders.

“There is a critical distinction to be made between a harsh childhood and a childhood lived in a harsh environment,” said Spikins of her work – an important thing to consider when we imagine what our ancestors endured growing up in the Paleolithic Era.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

Explaining Why We Have Such Big Brains in Just a Few Letters

G, C, A, T to be exact. Only a slight stretch of our DNA make the difference between us and our chimpanzee cousins. When embedding the bit of genetic information into mice, scientists found that the rodents’ brains grew significantly larger than usual.

“It’s likely to be one of many DNA regions that’s critical for controlling how the human brain develops,” says Debra Silver, on the region they chose. Silver is a neurobiologist at Duke University Medical School.

It is likely that this accounts for the massive difference in brain size between humans and our closest living relative, the chimpanzee – a difference of anywhere between two and four times larger by current estimates. While also having larger brains, people also have many more neurons than their simian friends, and many more connections, or synapses, occurring between each.

Scientists have long sought to determine what genetic basis we have for abstract thought as well as valuing logic and complex emotions – our capacity to develop languages and artwork, concepts that have long been associated with larger brain size. Currently, we have a wealth of evidence that our fellow hominids the Neanderthals were also capable of artwork and tool making, presenting a rather different picture than our old stereotypes of mindless barbarians. The Human Genome Project, concluded in 2004, revealed that humans and chimpanzees have DNA approximately 95 percent identical, establishing that we have more in common with chimps than mice do with rats. Silver’s latest interest, however, is to learn more about those regions in the genome that differ. Chimps do have capacity for tool making, using straw to catch termites, but their linguistic capacity, aside from facial reading, is still being explored.

Silver and her researchers isolated a gene that aids in brain development and removed the DNA region near it, which they proceeded to plant into mice. One group received human DNA, and the other received DNA extracted from chimps.

“What we discovered is that the human DNA turned on gene activity in neural stem cells, and these are cells which produce the neurons of our cerebral cortex,” said Silver.

The mice that were born yielded brains 12 percent larger than the brains of mice who received chimp DNA. The findings were published in Current Biology.

Now, Silver’s team will begin an investigation of how differently mice with larger brains will behave as they mature, knowing that they have only begun to scratch the surface. At the same time, they are looking for other genes that are specific to humans.

Of particular interest is within a vestigial genetic region known popularly as “junk DNA,” that which evidences our common descent from other, more primitive lifeforms, but until recently was believed to serve no specific purpose of its own, since this region doesn’t code for any active proteins in the body. Currently, however, researchers suspect that this region is critical for turning on and off genes as new cells are formed. Their ultimate function, if any at all, still remains a mystery.

“We have very little scientific information about the actual functions of those regions,” said Katie Pollard, who researches human and chimp DNA from the University of California, San Francisco, in a recent interview with NPR.

Many of the ways in which we differ from chimps can be found within the junk DNA, and many researchers like Pollard are still looking to meet that gap. As impressive as the results reported in the study may have been, it is difficult to predict what effect it may have on the mice. It’s preferential to see directly how either people or chimps are affected by the region’s presence, but then the research touches on ethical grounds.

“We’re talking about humans and chimpanzees here, and you cannot experiment on either of those,” notes Pollard. “And so it’s very challenging to prove causation.”

Challenging, sure, but not necessarily impossible either. Already, Pollard and her colleagues are experimenting with lab cultivated cells from chimps and humans, raised in Petri dishes.

“We can now actually generate the equivalent of embryonic brain cells and tissues that are human or chimpanzee,” says Pollard. “And, using genome engineering techniques, we can start to study the effects of switching the human and the chimp sequences in these primate cell lines.”

As their work progresses, the team hopes that soon they may find specific sequences in the DNA that are human by their very definition – opening the gateway of questioning precisely what characteristics make us human, and how distinct we really are from our living primate relatives. The difference may be far less than we ever imagined.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.