Did Neandertals Wear Ornaments?

A small but tantalizing find provides further evidence for Neandertal culture.  Working in the foothills of the Alps just north of Venice, Italy, researchers have discovered and analyzed a small marine shell that originally came from about 60 miles away.  It was thinly coated with a dark red substance that turns out to be pure hematite and was most likely used as a pigment.  One possibility is that the shell was used as an ornament.

The paper, freely available online in the journal PLoS One, dates the shell’s pigmentation to a period just before 45,000 years ago, right before the arrival of so-called “modern” humans in Europe. 

Photo Caption: A shell possibly "painted" by Neandertals about 45,000 years ago.  Photo available from PLoS One.

According to the paper, “deliberate transport and coloring of an exotic object, and perhaps its use as pendant, was a component of Neandertal symbolic culture, well before the earliest appearance of the anatomically modern humans in Europe.”

Quoting more of the paper, “this discovery adds to the ever-increasing evidence that Neandertals had symbolic items as part of their culture.”

Debates about Neandertal culture have intensified recently, in part because of genetic evidence of interbreeding between Neandertals and the modern humans coming into Asia and Europe.  While these modern humans began their migration out of Africa about 80,000 years ago and probably interbred around 55,000 years ago, they did not reach Europe until more like 40,000 years ago.  If all these dates hold up in future research, this shell does provide a small but intriguing hint about the culture of Neandertals at just about the time of their encounter with “modern” humans. 

So who exactly is modern?  The differences between ourselves (the humans we like to call “modern”) and the Neandertals are not as great than we once imagined.  The paper ends with these words: “Future discoveries will only add to our appreciation of Neandertals shared capacities with us.”

The paper, entitled "An Ochered Fossil Marine Shell From the Mousterian of FumaneCave, Italy," appears in the current issue of PLoS One and is freely available online.

The Rise of Agriculture: New Findings, Added Complexity

In the grand story of human origins, the invention of agriculture is one of the most pivotal chapters.  It is generally agreed that farming first arose in the Fertile Crescent about 12,000 years ago.  But did it arise in at one end of the Crescent and spread to the other?  Or did it arise independently in various locations across the entire region, from modern Israel to modern Iran? 

Photo caption: Hordeum spontaneum, wild barley from Chogha Golan, Iran. [Image courtesy of TISARP]

New research suggests that agriculture arose independently at various locations. While the newly developed agricultural techniques and selected grains probably spread quickly, newly published evidence suggests that the inventive process itself was widespread.  The research, conducted by Simone Riehl from the University of Tübingen in Germany along with colleagues from the Tübingen Senckenberg Center for Human Evolution and Paleoecology, is published in the July 5, 2013 issue of the journal Science.

A key debate in human evolution is whether momentous changes such as agriculture occur in big, rapid, and isolated bursts, or whether such grand changes are the cumulative result of smaller changes widely distributed over vast areas and long periods of time.  This new evidence seems to support the view that changes are distributed and cumulative rather than rapid.

Field work in Chogha Golan, Iran, led Riehl’s team to the discovery of wild, progenitor versions of barley, lentil, and wheat.  At the same site, early domesticated forms of these same plants are found, suggesting that the domestication occurred onsite.  Domesticated plants and animals form the core of agriculture and the economic basis for the rise of human cities and civilization.  

Tools and figurines were also found, dating from 12,000 to around 9,800 years before the present. The rise of agriculture in this region during this period set the stage for the growth of human population, the development of cities, and the rise of ever-more complex cultures.

The article is entitled "Emergence of Agriculture in the Foothills of the Zagros Mountains of Iran."  It appears in the 5 July 2013 issue of the journal Science.  

We Are What We Ate: Diet and Human Evolution

At a key moment in human evolution, our diet expanded and became more diverse, setting the stage for humans to draw on a wider range of food sources to feed expanding brains.

Four academic papers published together in the June 3, 2013 issue of the Proceedings of the National Academy of Sciences report on new methods of studying the carbon found in ancient teeth, going back more than 4 million years.  Ancestors living then ate pretty much what apes eat today, a diet of mostly leaves and fruits.  Then about 3.5 million years ago, a major shift occurs. 
Caption:This is an artist's representation of Paranthropus in southern Africa more than 1 million years ago.  Credit:Illustration courtesy ArchaeologyInfo.com/ScottBjelland.  Usage Restrictions: None

  

The old food sources remained in use, but new sources are added.  Researchers came to this conclusion by analyzing the carbon isotopes still present in ancient teeth.  After examining 175 specimens from 11 different species, they concluded that a key shift occurred at about 3.5 million years ago.  At that point, at least some of our ancestors were supplementing the usual foods by turning to grasses or sedges—or to the animals that graze on them.  These ancestors, including Australopithecus afarensis (best known as the famous “Lucy”), became more diverse in their food sources.

The earliest known evidence suggests that at about this same time, our human ancestors were making tools and using them to butcher large animals for food.  If these animals ate grasses, the carbon would have entered the human diet that way.  Another possibility is that human ancestors were simply learning to identify other types of plants as food sources compatible with human metabolism.

The main point, however, is that at this critical 3.5 million year transition, human ancestors were become more variable in their diet and in their behavior.  Rather than being locked into one type of food source or one way to pursue food, they were becoming more varied in their diet and behavior.  This made it possible for them to exploit more sources of food, nourish even bigger brains, travel and thrive in new niches, and survive climate change cycles, particularly ancient African cycles of wet and dry periods. 

"We don't know exactly what happened," said Matt Sponheimer of Colorado University and one of the researchers. "But we do know that after about 3.5 million years ago, some of these hominids started to eat things that they did not eat before, and it is quite possible that these changes in diet were an important step in becoming human."

If becoming more varied and adaptable is the same as becoming more human, then this study provides an important insight into this process.  One of the papers (Wynn et al.) concludes with this sentence: “This dietary flexibility implies unique landscape use patterns and malleable foraging behavior within a narrow time from of a single species.”  In other words, they were able to adjust quickly, seizing new opportunities and adapting to environmental changes. 



 

Deep Brain Cognitive Enhancement: The Latest News

The search for new methods of cognitive enhancement has just reached new depths.  Researchers in Austria and the UK report exciting new evidence that a form of noninvasive deep brain stimulation enhances the brain’s ability to do arithmetic. 

"With just five days of cognitive training and noninvasive, painless brain stimulation, we were able to bring about long-lasting improvements in cognitive and brain functions," says Roi Cohen Kadosh of the University of Oxford and lead author of the report that appears in the May 16, 2013 issue of Current Biology.  His comments were provided by the journal.

Photo Credit.  Photo by Ad Meskens of an original oil painting by Laurent de La Hyre (French, 1606-1656).  The title of the painting is Allegory of Arithmetic (Allegorie van de rekenkunde) and it dates to about 1650.  The original painting is in the Walters Art Museum, Baltimore, Maryland.  It was photographed on 18 July 2007 by Ad Meskens, who has made it freely available with proper credit.

In this study, the team used a form of noninvasive deep brain stimulation known as “transcranial random noise stimulation” or TRNS.  The TRNS input was combined with more traditional math training and drills.  Twenty-five young adults, males and females, were divided into two groups, one receiving math training with the TRNS and the other receiving math training combined with a “sham” version of TRNS, a kind of placebo. 

Not only did those who received TRNS do well immediately, but the benefits lasted for at least six months.  In addition, brain monitors detected different brain activity for those receiving TRNS.  This suggests that TRNS modifies brain function.

According to Cohen Kadosh, "If we can enhance mathematics, therefore, there is a good chance that we will be able to enhance simpler cognitive functions."

In the paper’s conclusion, the authors state that TRNS “can enhance learning with respect to high-level cognitive functions, namely algorithmic manipulation and factual recall in mental arithmetic. When this learning is based on deep-level cognitive processing, as is the case for calculation arithmetic, such enhancements are extremely long-lived both behaviorally and physiologically.

Then they sum up with these words:

Both the behavioral and physiological changes displayed extreme longevity, spanning a period of 6 months, but only when learning involved deep-level cognitive processing. By its demonstration of such longevity and, for the calculation task, generalization to new, unlearned material, the present study highlights TRNS as a promising tool for enhancing high-level cognition and facilitating learning. These findings have significant scientific and translational implications for cognitive enhancement in both healthy individuals and patients suffering from disorders characterized by arithmetic deficits.

The paper, Snowball et al.: "Long-Term Enhancement of Brain Function and Cognition Using Cognitive Training and Brain Stimulation," appears in the May 16, 2013 issue of Current Biology. 

Stem Cell Advance and Cloning Debates

An important breakthrough in stem cell medical research is likely to re-ignite an ethical debate about human cloning. 

Researchers at the Oregon Health & Science University reported on May 15 that they have succeeded for the first time in human “somatic cell nuclear transfer” or SCNT, a process that the public often refers to simply as cloning.  Oregon researchers were able to transfer the nucleus from one human cell into a donated human egg from which the nucleus had been removed, essentially the same process that led to the creation of Dolly the sheep more than fifteen years ago. 

Caption: The first step during SCNT is enucleation or removal of nuclear genetic material (chromosomal) from a human egg. An egg is positioned with holding pipette (on the left) and egg's chromosomes are visualized under polarized microscope. A hole is made in the egg's shell (zone pellucida) using a laser and a smaller pipette (on the right) is inserted through the opening. The chromosomes then sucked in inside the pipette and slowly removed from the egg.  Credit: Cell, Tachibana et al. Usage Restrictions: Credit Required.

 

While other teams have achieved nuclear transfer with human cells, none has been able to produce an embryo that developed long enough to yield human embryonic stem cells.  The Oregon team, led by Shoukhrat Mitalipov, achieved this long-desired goal.

 

Even more remarkably, the Oregon team achieved SCNT repeatedly and with high efficiency, in one case producing a stem cell line for every two donated eggs. Along with other researchers around the world, Mitalipov’s team has discovered many ways to fine-tune the nuclear transfer process, making it far more demanding technically than when Ian Wilmut’s team first created Dolly.

But just as we learned from Dolly, any major technical advance in somatic cell nuclear transfer is likely to trigger public controversy about cloning and about the social impact of science.  While nearly everyone applauds the goal of the Oregon research—better understanding and treatment of disease—not everyone will like the way they went about their work.

For one thing, the result of successful nuclear transfer is a kind of embryo.  Mitalipov’s paper, published in the June 6, 2013 issue of the journal Cell (online on May 15), repeatedly refers to this new entity as the “SCNT embryo.”  Is a “SCNT embryo” a “real” embryo?  If an embryo is the result of fertilization, then of course a “SCNT embryo” is not a normal or real embryo.  But if an embryo is defined by its potential to develop, then a SCNT embryo probably is very close to a normal or real embryo, biologically at least.

Suppose we accept that a SCNT embryo is real enough to warrant the same protection as embryos created by IVF.  Is it legitimate to create such an embryo for the express purpose of research that will destroy this SCNT embryo?  Many people object to this, and major religious institutions such as the Catholic Church have been unambiguous in their denunciation of this research. 

On the other hand, a few religious groups have specifically endorsed this research.  One of the clearest statements of support is entitled “Cloning Research, Jewish Tradition and Public Policy.”  The statement, published in 2002, speaks for all major groups within American Judaism: 

Moreover, our tradition states that an embryo in vitro does not enjoy the full status of human-hood and its attendant protections.  Thus, if cloning technology research advances our ability to heal humans with greater success, it ought to be pursued since it does not require or encourage the destruction of life in the process.

Another statement in support comes from a study committee in the United Church of Christ, which released this statement in 1997: 

...we on the United Church of Christ Committee on Genetics do not object categorically to human pre-embryo research, including research that produces and studies cloned human pre-embryos through the 14th day of fetal development.”

For more religious statements on embryo research, check out God and the Embryo, especially the appendics. 

I personally agree with the statements quoted above.  So I support the research performed in Oregon.  But I have to admit that among people with religious commitments, I am in a minority.  As much as I wish it were otherwise, I expect that many will object to the idea that Mitalipov’s group has created and destroyed embryos for research.

Some will argue that the technology of induced pluripotent stem cells (iPSCs) makes the use of embryos unnecessary.  While it is true that iPSC technology is a remarkable and promising advance, so far the field has run into unexpected technical complications in its quest to produce pluripotent stem cells that function like cells from embryonic sources.  A great attraction of iPSCs—beyond the fact that no embryos are involved—is that they are a genetic match to the donor.  What the Oregon breakthrough provides is the best of both: embryonic quality in donor-specific cells. 

Others will object because they don’t like human cloning—understood now as the use of SCNT to produce a child.  They will see the Oregon breakthrough as ushering in the era human reproductive cloning, and they will see this as reason enough to ban any further advances in SCNT technology.

Far more sensible, I think, would be a moratorium on human reproductive cloning.  What the Oregon group has achieved does make it more likely that someone somewhere might try to offer cloning as a reproductive technology.  The problem is that using Mitalipov’s techniques, they might succeed in creating an embryo that survives but that is beset by many unforeseeable health problems.

If we have learned anything in the past fifteen years, it is that SCNT is a tricky and complex process.  Just because Mitalipov’s team learned how to create the SCNT embryo that is healthy and viable through the blastocyst stage does not mean that anyone knows how to create an SCNT child.  Too many things could go wrong, and only now are we beginning to get some idea of how these potential problems might arise.

Someday, many decades in the future, we may understand these problems so well that we can solve them technically.  If that day ever comes, then those who come after us will have to ask: is a cloned child a good idea.  Right now we do not even have to ask that question because an SCNT is an unsafe idea. 

The press release from The Oregon Health and Science University that announces this advance makes this claim:

One important distinction is that while the method might be considered a technique for cloning stem cells, commonly called therapeutic cloning, the same method would not likely be successful in producing human clones otherwise known as reproductive cloning. Several years of monkey studies that utilize somatic cell nuclear transfer have never successfully produced monkey clones. It is expected that this is also the case with humans. Furthermore, the comparative fragility of human cells as noted during this study, is a significant factor that would likely prevent the development of clones.

The Oregon release then quotes Mitalipov:

"Our research is directed toward generating stem cells for use in future treatments to combat disease," added Dr. Mitalipov. "While nuclear transfer breakthroughs often lead to a public discussion about the ethics of human cloning, this is not our focus, nor do we believe our findings might be used by others to advance the possibility of human reproductive cloning."

The article is entitled "Human Embryonic Stem Cells Derived by Somatic Cell Nuclear Transfer" and appears in the May 15 issue of the journal Cell. 

Lights and Brains: Injectible LED's Interact with Brain Cells

The quest to put computers in the brain has just come a step closer.  Tiny LED lights have been implanted deep in the brains of rodents.  The LEDs themselves are the size of individual neurons.  They are packaged with other tiny sensors into an ultrathin, flexible device.  The whole device is small enough to be implanted using a needle that positions the device at precise sites deep in the brain. 

Once implanted, the device communicates directly with the brain at the level of cells.  It communicates wirelessly with a module mounted above the rodent’s head, one small enough not to interfere with activity and removable when not in use.  The device itself is completely contained within the brain where it was implanted without any damage to surrounding cells.  Signals sent through the device stimulate genetically modified brain cells, signaling for example for the release of neurotransmitters such as dopamine. 

Photo Credit: MicroLED device next to a human finger.  Image courtesy of University of Illinois-Urbana Champaign and Washington University-St. Louis.

 

"These materials and device structures open up new ways to integrate semiconductor components directly into the brain," said team co-leader John A. Rogers according to a press release from the University of Illinois.  "More generally, the ideas establish a paradigm for delivering sophisticated forms of electronics into the body: ultra-miniaturized devices that are injected into and provide direct interaction with the depths of the tissue."

The device itself is a feat of engineering requiring the effort of an international team based in China, Korea, and at multiple centers across the US.  By miniaturizing the device to the cellular scale and by creating a totally wireless interface, researchers overcame several challenges at once.  For example, larger implantable devices always run the risk of creating scars or lesions in the brain, which may cause serious problems.   "One of the big issues with implanting something into the brain is the potential damage it can cause," team co-leader Michael Bruchas said. "These devices are specifically designed to minimize those problems, and they are much more effective than traditional approaches."

In addition, because this device communicates and receives its power wirelessly, there are no wires or optical fibers passing from the brain to the outside world.  Previous devices were larger and nonflexible. They were implanted only on the surface of brain structures, but this new device is implantable deep within those structures and able to interact with units as small as a single cell.

Along with the LED lights, the device includes temperature and light sensors, microscale heaters, and electrodes that can stimulate and receive brain electrical activity.  Power to the device is provided wirelessly through a radio frequency system. 

It is impossible to predict the future of efforts to connect brains and computers. This work obviously represents a significant advance toward that end.  "These cellular-scale, injectable devices represent frontier technologies with potentially broad implications," Rogers said. Being able to monitor and trigger the brain of living animals at the cellular level is likely to become a profoundly valuable tool for research.  Medical research, too, is also likely to be affected, not just in responding to patients with paralysis but also in research and perhaps even therapy in other diseases involving the brain or other organs, where these devices are also implantable. 

Some, of course, will speculate about even wider implications for this technology.  Will it open the way to control people by controling their brains?  Perhaps.  Will it open the way for our brains to communicate with computers and the internet?  There is little doubt that this step will inspire more work along those lines. 

This article is entitled "Injectable, Cellular-Scale Optoelectronics with Applications for Wireless Optogenetics" and is published in the April 12, 2012 issue of the journal Science, a publication of the American Association for the Advancement of Science. 

The Two Million Year Question

Careful studies of 2-million year old human-like fossils just published in the April 12, 2012 issue of Science raise more questions than they answer.

These papers provide highly detailed information about the teeth, rib cage, hands, and feet of this strange relative, known to scientists as Australopithecus sediba.  But we still do not know the answer to the biggest question of all.  How does sediba fit in the human family tree?  Is sediba a direct human ancestor?  If not, why are they so similar to us in some respects?

Photo Credit: The reconstructed skull and mandible of Australopithecus sediba.Reconstruction by Peter Schmid, Photo by Lee R. Berger. Image courtesy of Lee R. Berger and the University of the Witwatersrand.

The teeth are mostly like those of Australopithecus africanus but also quite a bit like the earliest examples of the genus Homo.  That is surprising.  For some experts, it calls into question the standard view that Homo evolved from Australopithecus afarensis, most commonly known as “Lucy.” 

The new analysis suggests an evolutionary pathway from africanus to sediba to Homo.  In that case, Lucy is a relative but not an ancestor.  Sediba is. 

Not so fast, others insist.  The first examples of Homo may go back to 2.3 million years ago, long before sediba appears at just under two million years ago.  Lucy and her afarensis kin lived much earlier, enough to be ancestral to Homo. 

Based on what we know now, the debate will continue because the facts just do not line up neatly or offer a simple story.  "Our study provides further evidence that sediba is indeed a very close relative of early humans, but we can't definitively determine its position relative to africanus,” study co-author Debbie Guatelli-Steinberg said according to a release from Ohio State University.

What these studies do provide is a remarkably complete picture of what early human-like ancestors look like.  They also provide another surprise.  Despite having a foot with a narrow heel, similar to chimpanzees, sediba definitely walked upright, maybe even using a somewhat awkward never known before to scientists.  They were clearly not knuckle-walkers, like the apes, but they were not nearly as graceful as the humans who followed.  It seems they walked upright differently.  

For now, what all this suggests is that the story of our deep ancestry is more complex than we usually imagine.  Straight ancestral lines are hard to draw.  More finds may help sort things out.  But they may also add new complexity.  The way it looks, multiple forms of early human life may have existed at once.  They differed slightly from each other and also in the degree to which they resemble us.  That makes it very hard to sort out the lineages.  

Is sediba a direct human ancestors?  Yes, at least according Lee Berger, who discovered sediba in a pit in northern South Africa in 2008.  Most experts, however, argue no, mainly the dates are out of line.  What difference does it make?  Perhaps the biggest significance of this debate is to show us that the more we know, the more we see a complex picture of multiple species and perhaps interweaving lineages, making it all the more remarkable that we are here at all. 

This research is published as a set of six research reports in the April 12, 2012 issue of the journal Science, a publication of the American Association for the Advancement of Science.