Earliest Known Human Had Neanderthal Qualities

Aug. 22, 2008 -- The world's first known modern human was a tall, thin individual -- probably male -- who lived around 200,000 years ago and resembled present-day Ethiopians, save for one important difference: He retained a few primitive characteristics associated with Neanderthals, according to a series of forthcoming studies conducted by multiple international research teams.

The extraordinary findings, which will soon be outlined in a special issue of the Journal of Human Evolution devoted to the first known Homo sapiens, also reveal information about the material culture of the first known people, their surroundings, possible lifestyle and, perhaps most startling, their probable neighbors -- Homo erectus.

"Omo I," as the researchers refer to the find, would probably have been considered healthy-looking and handsome by today's standards, despite the touch of Neanderthal.

"From the size of the preserved bones, we estimated that Omo I was tall and slender, most likely around 5'10" tall and about 155 pounds," University of New Mexico anthropologist Osbjorn Pearson, who co-authored at least two of the new papers, told Discovery News.

Pearson said another, later fossil was also recently found. It too belonged to a "moderately tall -- around 5'9" -- and slender individual."

"Taken together, the remains show that these early modern humans were...much like the people in southern Ethiopia and the southern Sudan today," Pearson said.

Building On Leakey's Work

Parts of the Omo I skeleton were first excavated in 1967 by a team from the Kenya National Museums under the direction of Richard Leakey, who wrote a forward that will appear in the upcoming journal.

Leakey and his colleagues unearthed two other skeletons, one of which has received little attention. Two of the three skeletons found at the site have been a literal bone of contention among scientists over the past four decades. Reliable dating techniques for such early periods did not exist in the late 60's, and the researchers could not agree upon the identity of the two skeletons.

From 1999 to the present, at least two other major expeditions to the southern Ethiopian site -- called the Kibish Formation -- have taken place, with the goal of solving the mysteries and learning more about what the area was like 200,000 years ago.

As evidenced by photographs showing the researchers followed by armed guards, work at this location proved challenging.

"It took us five plus days to get there from Addis," paleobiologist Josh Trapani of the Smithsonian Institution and the University of Michigan told Discovery News. "Once there, we had intense heat, hyenas outside camp, crocodiles in the river, many insects and two remarkable and very different groups of people, the Mursi and the Nyangatom on opposite sides of the river who were our partners in some of this work."

Primitive, Yet Still Like Us

The ordeals proved successful, as the scientists have recovered new bones for Omo I, some of which perfectly fit into place with the remains Leakey unearthed over 40 years ago.

Several scientists analyzed the bones, including a very detailed, comparative look at the shoulder bone by French paleontologist Jean-Luc Voisin. They concluded that, without a doubt, Omo I represents an anatomically modern human, with bones in the arms, hands and ankles somewhat resembling those of other, earlier human-like species.

"Most of the anatomical features of Omo are like modern humans. Only a few features are similar to more primitive hominids, including Neanderthals and Homo erectus," explained John Fleagle, distinguished professor in the Department of Anatomical Sciences at Stony Brook University in New York.

"Omo II is more primitive in its cranial anatomy," he added, "and shares more features with Homo erectus and fewer with modern humans."

Unlikely Neighbors

New dating of the finds determined that Omo II lived at around the same time and location as Omo I, indicating that Homo sapiens may have coexisted with Homo erectus, a.k.a. "Upright Man," who is believed to have been the first hominid to leave Africa.

Fleagle explained the detailed nature of the latest dating techniques that place both skeletons at around the 200,000-year-old period.

He said both skeletons were recovered from rocky geological layers, with "Adam" unearthed just above a layer of volcanic rock. Precise dates can then be calculated because "when volcanic rocks form, they start a radiometric clock that ticks at a regular rate."

Fleagle added, "By looking at the ratio of parent minerals and daughter minerals you can calculate when the rocks were initially formed."

Material Culture In A Different Environment

Anthropologist John Shea sifted through the Kibish dirt and rocks hoping to find evidence for early material culture.

He found it.

"The assemblages are dominated by relatively high-quality raw materials procured as pebbles from local gravels," Shea determined, adding that he unearthed stone tools flaked on both sides, hand axes, picks and spear-shaped objects. It appears that most were not retouched. So, once the early modern humans crafted their tools, they likely left them as is.

Trapani, who conducted a study on fossil fish at the site, said later-dated barbed bone points recovered from the site look remarkably like catfish spines, which "may be purely coincidental." Or, "alternatively, perhaps the spines impressed early hunters with their potential utility as flesh-piercing hunting implements."

Trapani added, "This may have come about through simple visual inspection or, perhaps -- more likely -- through painful lesson."

Living High on the Hog

Supporting Trapani's findings that large catfish, as well as Nile perch and other fish, were in abundance, studies on the site's geology indicate that conditions were wetter 200,000 years ago.

Yet another study, on the large mammal fauna at Kibish, found the humans were surrounded by big game.

Smithsonian Institution archaeobiologist Zelalem Assefa identified hippos, giraffes, elephants, zebras, rhinos, numerous other hoofed mammals and more.

"In terms of settlement strategy, the early modern humans at Kibish might have practiced some type of seasonal based settlement strategy -- possibly following the movement of big game," Assefa told Discovery News.

Perhaps his two most unusual finds were that very few remains for non-human primates and carnivores were found, which puzzles the researchers, but may suggest that the first known humans didn't have many, if any, animal predators.

Secondly, Assefa was surprised to find duiker (a small, shy antelope that usually prefers forest cover) and giant forest hog remains. The giant forest hog is the largest wild pig on Earth, weighing as much as 600 pounds. Since other parts of the site were probable grasslands, the presence of these two animals suggests a riparian forest must have also been nearby.

An Unfinished Story

Although Omo I may be the world's "Adam" for now, it's possible that modern humans emerged even earlier at some other place in Africa.

"We only have evidence for what we have found," Fleagle said, adding that there "almost certainly were modern individuals before Omo I."

He explained that Ethiopia's geology has deposits suitable to bone preservation and discovery, which is perhaps why so many fossil hominids have been excavated there over the years.

"Paleontology is a very opportunistic science," he concluded. "When we have a record of fossils in one place, we can reconstruct what happened there, but it is impossible to say what was going on in places from which there is no fossil record."

Why low-calorie sweeteners are 'more fattening than sugar'

One of the first rules of weight watching has always been: Put the sugar bowl at the back of the cupboard and use low-calorie sweeteners from now on.

But researchers suggested yesterday that dieters might be better sticking with sugar after all.

They think that a sweet taste can prompt the body to prepare for a large intake of calories.

When this does not arrive, the body then becomes confused and either demands more food or burns less energy - with the result showing on the scales.

"The data clearly indicate that consuming a food sweetened with no-calorie saccharin can lead to greater body-weight gain than the same food sweetened with high- calorie sugar," say the U.S. team behind the research.

They accept that the finding will seem baffling to those who have long recommended the use of sweeteners to control weight.

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Other artificial sweeteners such as aspartame which do not lead to the delivery of calories could have similar effects, the researchers said in the journal Behavioural Neuroscience, published by the American Psychological Association.

Scientists at Purdue University in West Lafayette, Indiana, fed some rats with yogurt sweetened with saccharin and others with yogurt sweetened with glucose, a natural sugar.

The saccharin-fed rats went on to consume more calories and put on more weight and body fat.

The research drew a critical reaction-from the food industry.

"This study oversimplifies the causes of obesity," said Beth Hubrich, a dietitian with the Calorie Control Council, representing companies which make diet foods and drinks.

"The causes of obesity are multi-factorial. Although surveys have shown that there has been an increase in the use of 'sugar-free' foods over the years, portion sizes of foods have also increased, physical activity has decreased and overall calorie intake has increased."

The council also said findings in animal studies might not be applicable to people, which the researchers acknowledged.

Davidson responded that the implication of the council's statement "that they, too, are interested in the health of the public seems insincere. If they were sincere, one might expect that they would be alarmed by findings from animal or human models suggesting that their products might be contributing to the obesity epidemic that continues to expand and do its damage."

Britons eat an average 150lb of pure sugar a year - more than 12lb per month.

The typical family gets through 52lb a month of sugar in its different forms.

The toll on health can be devastating. As well as causing dental decay, too much sugar can lead to obesity and type 2 diabetes, raising the risk of heart attack and stroke.

5 Ways to Beef Up Your Brain

By Andrea Thompson, Senior Writer

Forget where you left your keys this morning? Or maybe you left your umbrella in the office before a rainy evening.

Don't worry, it's probably not a sign of Alzheimer's — everyone is a little forgetful now and then.

But the prevalence of Alzheimer's and other types of dementia, which slowly deteriorate the brain's capacity to make new memories, retrieve older ones and perform other mental and physical tasks, is on the rise as the baby boomer generation hits retirement age. A 2007 Alzheimer's Association report estimated that more than 5 million Americans were currently living with the disease and that that total could reach 16 million by 2050.

Scientists are still trying to unravel the many mysteries of the brain — how our brain processes information, how memory works, how the brain ages and how diseases like Alzheimer's develop — so that we better understand our own minds and how to keep them healthy.

But while there is still a lot to learn about our noggins, several studies have worked out a few ways to help keep your thinking organ in shape, now and as you age.

1. Eat Your Brain Food

You are what you eat, or at least your brain is. A diet of junk food can junk up your brain, as things like trans fats and saturated fats, common in heavily processed foods, can negatively affect the brain's synapses. Synapses connect the brains neurons and are important to learning and memory. On the other hand, a balanced diet rich in omega-3 fatty acids — found in salmon, walnuts and kiwi fruit — can give the synapses a boost and help fight against mental disorders from depression to dementia.

2. Hit the Gym

Giving the rest of your body a workout can also improve your memory, make you think more clearly and decrease the risk of developing cognitive diseases, several studies have suggested. Because exercise is a mild stressor to your body, eating up the precious energy needed by the brain, it triggers the release of chemicals called growth factors that make the brain's neurons stronger and healthier. Half an hour every other day will do it, experts say. And don't forget to stretch: Stretching can help reduce stress, which can impact the memory centers of your brain.

3. Mind Benders

Give your brain a workout, too, with brainteasers, crossword puzzles and memory games — studies have shown that using these tools to stay mentally active can reduce the risks of developing dementia by building and maintaining a reserve of stimulation in your brain. Even following the current political campaign can provide a boost to the systems that control attention and learning that are hard-wired into the brain.

4. Memory tricks

Keeping information stored in your memory banks and retaining that memory with age may also be a simple matter of mind control. For example, confidence in your cognitive abilities could actually affect how well your memory functions, particularly for the elderly. Because some older adults tend to blame memory lapses on age, regardless of whether or not that is the cause, they can keep themselves from even really trying to remember. Prediction can also enhance memory: If you have a good idea of the information you'll need to recall later, you're more likely to remember it.

5. Give it a Rest

Sleep gives your brain a chance to replay the memories of the day and consolidate them for long-term storage. One study suggested that the brain can do its reviewing much faster when you're asleep than when you're wide awake — so no more all-nighters, students. A 90-minute mid-afternoon nap can even help solidify long-term memories, such as events or skills you are trying to master. Siesta anyone?

Of course, none of these mind-enhancing tips is fool-proof. Some studies have suggested that developing Alzheimer's and other types of dementia is partly a matter of genetics.

One such study, presented in July at the Alzheimer's Association's International Conference on Alzheimer's Disease, hinted at a connection between mothers who develop Alzheimer's and the chances their children will become afflicted in old age. Another suggests that having a specific pattern of proteins is a risk factor for the debilitating disease.

But for now, no one can predict exactly who will or won't develop dementia. While scientists work on better indicators and cures, doing your own part to keep your body and brain healthy is probably the best you can do.

A Hormone That Enhances One’s Memory Of Happy Faces

ScienceDaily — Oxytocin was originally studied as the “milk let-down factor,” i.e., a hormone that was necessary for breast-feeding. However, there is increasing evidence that this hormone also plays an important role in social bonding and maternal behaviors. A new study scheduled for publication in the August 1st issue of Biological Psychiatry now shows that one way oxytocin promotes social affiliation in humans is by enhancing the encoding of positive social memories.

Adam J. Guastella, Ph.D. and his colleagues sought to evaluate the effects of oxytocin on the encoding and recognition of faces in humans. They recruited healthy male volunteers and in a double-blind, randomized design, administered either oxytocin or a placebo. They then presented a series of happy, angry and neutral human faces to the volunteers on a computer screen. Participants returned the following day where they were presented with a collection of faces and asked to distinguish the new faces from ones that they saw on the prior day. The results revealed that those who received oxytocin were more likely to remember the happy faces they had seen previously, more so than the angry and neutral faces. The results revealed that those who received oxytocin were more likely to remember the happy faces they had seen previously, more so than the angry and neutral faces.

Dr. Guastella notes that the “findings are exciting because they show for the first time that oxytocin facilitates the encoding of positive social information over social information that is either neutral or negative.” John H. Krystal, M.D., Editor of Biological Psychiatry and affiliated with both Yale University School of Medicine and the VA Connecticut Healthcare System, comments on the findings: “The findings from Guastella and colleagues provide new evidence about a chemical system in the body that may help us to connect socially to other people. One could imagine that our ability to recall a particularly happy face at the end of a day full of social contacts could reflect an action of oxytocin.”

Social isolation can be a feature of several psychiatric disorders. The success of oxytocin in enhancing positive social memories raises the possibility that oxytocin, or drugs that might act like oxytocin in the brain, could be used to help people who are socially isolated and have difficulty making social connections. Future research will be needed to test this hypothesis.

Neanderthals Didn't Mate With Modern Humans, Study Says

Ker Than
for National Geographic News

August 12, 2008

Neanderthals and anatomically modern humans likely did not interbreed, according to a new DNA study.

The research further suggests that small population numbers helped do in our closest relatives.
esearchers sequenced the complete mitochondrial genome—genetic information passed down from mothers—of a 38,000-year-old Neanderthal thighbone found in a cave in Croatia. (Get the basics on genetics.)

The new sequence contains 16,565 DNA bases, or "letters," representing 13 genes, making it the longest stretch of Neanderthal DNA ever examined.

Mitochondrial DNA (mtDNA) is easier to isolate from ancient bones than conventional or "nuclear" DNA—which is contained in cell nuclei—because there are many mitochondria per cell.

"Also, the mtDNA genome is much smaller than the nuclear genome," said study author Richard Green of the Max Planck Institute for Evolutionary Biology in Germany.

"That's what let us finish this genome well before we finish the nuclear genome," he said.

The new findings are detailed in the August 8 issue of the journal Cell.

A Small Population

The new analysis suggests the last common ancestor of modern humans (Homo sapiens) and Neanderthals lived between 800,000 and 520,000 years ago. This is consistent with previous work on shorter stretches of Neanderthal DNA.

Contrasted with modern humans, Neanderthals exhibited a greater number of letter substitutions due to mutations in their mitochondrial DNA, although they seem to have undergone fewer evolutionary changes overall.

The fact that so many mutations—some of which may have been harmful—persisted in the Neanderthal genome could indicate the species suffered from a limited gene pool. This might be because the Neanderthal population was smaller than that of Homo sapiens living in Europe at the time.

A small population size can "diminish the power of natural selection to remove slightly deleterious evolutionary changes," Green said. The researchers estimate the Neanderthal population living in Europe 38,000 years ago never reached more than 10,000 at any one time.

his could have been a factor in their demise, Green said.

Homo neanderthalis first appeared in Europe about 300,000 years ago but mysteriously vanished about 35,000 years ago, shortly after the arrival of modern humans—Homo sapiens—in Europe.

"If there were only a few, small bands of Neanderthals, barely hanging on, then any change to their way of life could have been enough to drive them to extinction," Green said.

"One obvious change would have been the introduction of another large hominid—modern humans."

Stepping Forward

Stephen Schuster, a molecular biologist at Pennsylvania State University, said the new study should silence a lot of theories about interbreeding between Neanderthals and modern humans.

The study shows that "at least for the maternal lineage, there are no traceable genetic markers that suggest admixture of Neanderthals and modern humans," he said.

Schuster added that the researchers were exceptionally careful to isolate the Neanderthal DNA.

"Many more precautions were taken to ensure that no contamination with human DNA has flawed the analysis," he said, noting that researchers sequenced each letter about 35 times to be sure of their work.

"This was the weak point of previous reports," said Schuster, who was not involved with the study.

Thomas Gilbert, an ancient DNA expert at the University of Copenhagen in Denmark who also was not involved in the study, called the research a "step forward" and a taste of what might come when the Neanderthal nuclear DNA is finished.

The team's argument that the Neanderthal population was small 38,000 years ago is speculative, Green said, but "it's better than what we could have said before."

Trigger for Learning Discovered

By Kirsten Houmann, Ivanhoe Health Correspondent

ORLANDO, Fla. (Ivanhoe Newswire) -- In a study with surprising results, scientists recently identified a protein necessary for learning.

The protein, called Otx2, works with cells called parvalbumin cells to enable the brain to learn at critical periods of development. Parvalbumin cells are responsible for making connections in the part of the brain that processes visual information. They also receive information from the eye. These cells, in cooperation with the Otx2 proteins, encourage brain plasticity, or the ability to learn.

"There's one cell between the visual input and the actual plasticity, and that's where we made the surprising finding -- that a particular protein used very early in the fetus … is recycled, or reused, in a very specific way after birth to induce a plastic period," senior investigator Takao Hensch, Ph.D., professor of molecular and cellular biology at Harvard University and professor of neurology at Children's Hospital Boston, told Ivanhoe.

This key protein is first responsible for forming the head of a fetus, Dr. Hensch explained.

After studying the function of parvalbumin cells in mice, Dr. Hensch and his colleagues found the Otx2 proteins are sent to these cells by the retina, triggering critical periods of brain plasticity.

Dr. Hensch said developmental disorders like autism are a result of impaired timing of these learning "windows," like the one during which children learn to read. He said he hopes the discovery of this protein will eventually lead to new treatments for disorders like autism, and brain injuries.

"If you have a brain injury in adulthood, it's very hard to recover from that; but if you knew how to switch on the brain plasticity, and basically rejuvenate the brain, then maybe you could accelerate or help out the degree of recovery from injury," he said.