There’s been much to say over the past few years about the possibility of significant interactions – and even interbreeding – between early members of our species, Homo sapiens, and our evolutionary cousins, Neanderthals. But now, new analysis of Neanderthal remains from western Russia casts doubt on the notion that we coexisted at all. Instead, the Neanderthals of western Russia appear to have died out before we even arrived. Results of this study were reported in last week’s online edition of the Proceedings of the National Academy of Sciences.

The research team, led by archaeologist Ron Pinhasi of University College Cork, questioned the analysis of two Neanderthal infants excavated over 10 years ago. The infants were found in the Mezmaiskaya Cave near the Caucasus Mountains of western Russia. Using carbon-14 dating, along with traditional stratigraphic methods (comparing ages of surrounding sediment layers), these infants were originally dated to about 30,000 years ago, just when humans were making their way into the region. This led many to wonder whether the two species ever came into contact, and to what extent.

But Pinahsi and his team were unconvinced the dating techniques were accurate. Central to their skepticism was the fact that the layers of sediment between which the infants were found were themselves dated incorrectly, skewing the original results.

But archaeological dating techniques have improved vastly over the past decade. So Pinhasi and his team put these new techniques to the test, by reanalyzing the Neanderthal infant remains directly. Specifically, Pinhasi harnessed the expertise of Thomas Hingham of Oxford University. Hingham has developed a new method of filtering samples that removes contaminants such as dirt, leaves, and collagen recovered from bone. This can give a far more accurate radiocarbon reading.

According to Hingham, “Previously, research teams provided younger dates which we now know are not robust, possibly because the fossil has become contaminated with modern particles. This latest dating evidences sheds further light on the extinction dates for Neanderthals in this key region.”

When putting the infant bone samples through the filter and dating them again, they found the infants to be 39,000 year old—9,000 years older than previously thought.

These infant remains had been strong evidence that humans and Neanderthals could have interacted with each other in western Russia. Now it is clear they were dead 9,000 years before humans showed up. Could this same story play out in other parts of the Europe and Asia?

“It now seems much clearer that Neanderthals and anatomically modern humans did not co-exist in the Caucasus, and it is possible that this scenario is also true for most regions of Europe,” says Pinhasi. He points to many instances of problematic dates for other archaeological sites excavated over the past several decades.

The western plains of Russia, like the Near East, were a prehistoric crossroads for early humans and our fossil ancestors. The revised analysis of the Mezmaiskaya Cave infants highlights the vast uncertainties we still hold surrounding the early expansions of our species, and our interactions with Neanderthals. But it also opens the door to new discoveries.

Anne Holden, a docent at the California Academy of Sciences, is a PhD trained genetic anthropologist and science writer living in San Francisco.

Image: Luna04/Wikimedia

Earth

The Gulf oil spill—the number of gallons spilled and the controversy surrounding the damage seems to top many lists this year. Nature even named Jane Lubchenco, head of NOAA, its newsmaker of the year for how she handled the crisis.

Natural disasters often took the front page in 2010 with the Haitian earthquake and the eruption of Eyjafjallajökull topping many lists. The hard-to-pronounce Icelandic volcano also made many of the best science images of the year lists.

DiscoveryNews ends the year on a positive note with “How Humans Helped the Earth in 2010,” a slide show with text concerning recent strides in alternative energy, species and habitat conservation efforts and individual efforts to go green (electric cars, white roofs and saving energy).

For more environmental news of the year, New Scientist’s Short Sharp Science has a great review and the Nature Conservancy has a best/worst list on its site.

Life

Teeny, modified life stole the spotlight this year—the J. Craig Venter Institute’s so-called “synthetic cell” and GFAJ-1—the bacteria that incorporates arsenic into its DNA—or so NASA scientists claimed.  Science writer Carl Zimmer discredited the arsenic bacteria paper on Slate; NASA author Felisa Wolfe-Simon defended herself in Science. Fun stuff!

The spread of pesky bedbugs was number six in Discover’s “Top 100 Science Stories of 2010.”

Nature’s great article this past summer on eradicating mosquitoes was among its readers’ top choices of the year.

Looking for something a little bigger and less controversial? New Scientist has “The coolest animals of 2010,” which includes a scorpion-eating bat and a fly thought to be extinct for over 160 years!

NPR found it was a very good year for Neanderthals—their genome was sequenced, brain examined and diet expanded.

Remarkably, the Census of Marine Life tops the BP oil spill in the Deep Type Flow blog’s biggest marine science stories of the year for its sheer numbers:

…over 500 research expeditions covering every ocean, over 2,500 scientists and the discovery of over 6,000 species new to science and published in over 2600 peer-reviewed papers.

Space

ScienceNow’s most popular story of all time, not just 2010, was “Does Our Universe Live Inside a Wormhole?” A wonderful theory that we also covered last spring.

Exoplanets, in part thanks to the Kepler mission, were all over the news this year—whether it had to do with size, atmosphere or number within a star system. Discover’s interview with local exoplanet hunter (and California Academy of Sciences Fellow) Geoff Marcy made number 11(!) on their 100 top stories list.

A little closer to home, Jupiter’s missing stripe and Neptune’s tale of cannibalism are included in New Scientist’s most popular space stories of 2010.

Our Moon and Saturn’s moons made news throughout the year and the top lists on Universe Today and Wired this week.

Universe Today also included SDO’s new views of the sun in their top stories list. Stunning!

Hubble celebrated its 20^th year in space this year by taking even more beautiful images. Several are included in Bad Astronomy’s “Top 14 Astronomy Pictures of 2010.”

Technology

Electric cars and NASA’s new foray into commercial spacecraft are included in Scientific American’s top ten stories of the year.

The Large Hadron Collider was very busy this year, and topped many lists. Another machine at CERN made news (and also topped Nature’s readers’ choice list) when it was able to capture antimatter for a sixth of a second!

Graphene not only garnered a Nobel Prize this year, the material (and it’s potential) also made news and top science lists of the year.

DiscoveryNews put plastics on their 2010 list—whether its finding new ways of removing plastic from the oceans or engineering smarter plastics.

What was your favorite science story of the year? Share with us by adding it to the comment section below!

Image by Les Stone, International Bird Rescue Research Center/Wikipedia

In a new study, published yesterday in the Proceedings of the National Academy of Sciences, researchers found that Neanderthals ate more than just meat. In addition, our ancient cousins cooked some of their foods, “suggesting an overall sophistication in Neanderthal dietary regimes,” according to the report.

Turns out that tooth tartar can tell a lot about a human species. By examining the calculus (that’s hardened plaque, not advanced mathematics) in dental remains of fossils from Belgian and Iraqi caves, the researchers recovered grains and phytoliths—evidence of plant-eating. (Neanderthals could’ve used some floss, eh?) Their diet was varied, according to the study :

Some of the plants are typical of recent modern human diets, including date palms (Phoenix spp.), legumes, and grass seeds (Triticeae), whereas others are known to be edible but are not heavily used today.

It appears Neanderthals cooked a good percentage of their grains and vegetables, but getting an accurate picture is difficult. From Scientific American:

To better assess starch grains from the samples, the researchers tried cooking similar plant products and found that heating the starches for more than half an hour rendered them largely unidentifiable, and thus they would not have been categorizable in fossil form.

Pallab Ghosh wrote in the BBC News that previous “chemical analysis of their bones suggested they ate little or no vegetables,” and anthropologists often speculated that Neanderthals disappeared 30,000 years ago due to their limited meat diet. This new evidence can now put that theory to rest, according to the authors.

Image from We El/Wikipedia

Human brains vs. Neanderthal brains

German and French researchers compared CT scans of human and Neanderthals at various growth stages and published their results in Current Biology. The brains in each species started out the same size and shape, but as each grew, their shapes changed. Both begin elongated, but human brains become more round and globular. Despite having similarly large brains, according to Science Now:

The differences suggest that Neandertals did not see the world the same way we do and may not have been as adept at language or forming complex social networks.

Human brains vs Chimpanzee brains

Excitingly, the same researchers had another similar study published last Friday. Using the same scanning techniques, they compared chimp and human brains at different ages. Unlike the Neanderthals, even at birth, the brain shape is different and in fact, according to the paper, “there is no overlap between the two species throughout ontogeny.” In addition, “the shape changes associated with this early “globularization phase” are unique to humans.”

Another study published last week in PLoS Genetics explains a by-product of this brain uniqueness—a weaker immune system. It all has to do with a type of white blood cells called natural killer cells, or NK cells. NK cells are crucial in fighting disease in both chimpanzees and humans, but they do a better job in chimps— chimps are not susceptible to diseases like HIV and malaria.

Human NK cells seem to have evolved differently. NPR had a great story on the research this week.

The kind of NK cells that are good for getting lots of blood to the developing fetus are not as good for dealing with infection, and vice versa.

And whereas the chimpanzees develop the cells good for infections,

The human system, on the other hand, seems to be optimized for getting lots of blood to the developing fetus so our big brains can grow the way they’re supposed to.

More Human Brain

Finally, how about two items that are good for the brain? A study published in PLoS One yesterday shows that the video game Tetris may reduce Post-Traumatic Stress flashbacks.  And Jonah Lehrer, one of our favorite neuroscience writers, has a great blog post in Wired today about the pleasure we get from preparing our own meals.

Image from Science- Credit: (baby skulls, L) P. Gunz et al., Current Biology, 20 (9 November 2010); (Adult skulls) Philipp Gunz/MPI EVA Leipzig