DNA from ancient site in Spain reshapes human family tree

 

Posted by Miguel Vilar on December 5, 2013

  

400,000-year-old hominid from Spain, news.nationalgeographic.com

Six weeks ago I suggested that 2013 was already the breakthrough year for molecular anthropology, but 2013 is ending with yet another highlight. Yesterday, Nature published a stop-you-in-your tracks piece that scrambles the scientific picture of our ancient relatives.  The world-leading Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany successfully sequenced the mitochondrial genome of a 400,000 year-old ancient human from Spain. The DNA suggests the specimen was maternally related to Denisovans, rather than Neanderthals, which leaves anthropologists puzzled and may be shifting branches around in the human family tree

Denisovan tooth, from www.genographic.com

The term Denisovan, distinct to both modern humans and Neanderthals, was coined just three years ago based on some limited tooth morphology, but predominantly on the distinct DNA sequenced from a 41,000 year-old toe bone found in central Asia. Since then, anthropologists have theorized that Denisovans were contemporary Asian “cousins” to Neanderthals found in Europe and the Middle East, and to modern humans who were already living throughout Africa and were venturing out of the continent for the first time 10,000 years earlier.

Wilma the Neanderthal, by Becky Hale.

That was the accepted story guiding anthropologists just last month.  Now the story has changed and we are scrambling to come up with a new narrative. Is this a different species ancestral to Denisovan, but not Neanderthals? Were there two movements out of Africa before the third and final migration that Homo sapiens took in the last 50,000 years? How many different species of hominids lived in Europe, Africa and Asia in the Pleistocene? And since these beings surely interbred, can we even call them separate species? When the dust settles, a new story of human ancestry will have surely emerged. What do you think was happening back then?

Our Universe Could be One Of Billions, Paper Explains

by William W. on September 22, 2013

Scientists believe they have found the first evidence that other universes exist after analyzing the data gathered by the European Space Agency’s Planck spacecraft.
Theories that our universe could be just one of billions — perhaps an infinite number – have been discussed for decades but until now they have lacked any evidence.
However, a few weeks ago, scientists published a new map of the cosmic microwave background – the ‘radiation’ left behind after the Big Bang that created the universe 13.8 billion years ago.
The map, based on Planck data, showed anomalies in the background radiation that, some experts say, could only have been caused by the gravitational pull of other universes outside our own.

Planck spacecraft and the cosmic microwave background.
Credit: ESA
http://spaceinimages.esa.int/Images/2013/03/Planck_and_the_Cosmic_microwave_background

“These anomalies were caused by other universes pulling on our universe as it formed during the Big Bang,” said Laura Mersini-Houghton, a theoretical physicist at the University of North Carolina at Chapel Hill.
“They are the first hard evidence for the existence of other universes that we have seen,” she said.
Mersini-Houghton, and her colleague Professor Richard Holman, at Carnegie Mellon University, published a series of papers from 2005 predicting what Planck would see.
In particular, they predicted that the ancient radiation permeating our universe would show anomalies generated by the pull from other universes.
The scientists analysing the Planck data have now published a paper acknowledging the anomalies exist and cannot be explained by conventional means.
“It may be that the statistical anomalies described in this paper are a hint of more profound physical phenomena that are yet to be revealed,” it said.
Planck gathered radiation from when the universe was just 3,700,000 years old – still glowing from the Big Bang. It has been travelling across space for 13.8 billion years and so is remarkably faint but still detectable.
In theory, that radiation should vary a little on the scale of galaxies and clusters of galaxies, but at much larger scales it should be evenly distributed.
Planck’s data showed the radiation is stronger in one half of the sky than the other. There is also a large ‘cold’ spot where the temperature is below average.
George Efstathiou, professor of astrophysics at Cambridge, who co-authored the papers setting out the Planck findings, said the suggestion that the data offered evidence for other universes was speculative but “very interesting”.
“Such ideas may sound wacky now, just like the Big Bang theory did three generations ago. But then we got evidence and now it has changed the whole way we think about the universe,” he said.

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Can Synesthesia in Autism Lead to Savantism?

By Dana Smith | December 4, 2013 |  

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Credit: Flickr/Andy Maguire

Daniel Tammet has memorized Pi to the 22,514th digit. He speaks ten different languages, including one of his own invention, and he can multiply enormous sums in his head within a matter of seconds. However, he is unable to hold down a standard 9-to-5 job, in part due to his obsessive adherence to ritual, down to the precise times he has his tea every day.
Daniel is a savant. He is also autistic. And he is a synesthete.
Daniel experiences numbers as having color, as well as shape and texture. This helps him perform amazing mathematical feats seemingly without effort, the answer simply materializing to him rather than having to calculate it out.
In an interview he gave with The Guardian, Daniel explained, “When I multiply numbers together, I see two shapes. The image starts to change and evolve, and a third shape emerges. That’s the answer. It’s mental imagery. It’s like maths without having to think.”
Clearly this man has an extraordinary brain. However, Daniel is perhaps not entirely unique, and it appears that the link between autism and synesthesia is more common than originally thought. This suggests that there is a potential common mechanism between these two conditions, which may even help to explain some of Daniel’s special savant abilities.
A new study published in the journal Molecular Autism from a team of researchers at the University of Cambridge now empirically shows that there is an almost three-fold higher occurrence of synesthesia in individuals with autism (18.9%), compared with that of the general population (7.2%). This increased prevalence implies that there is indeed a significant link between autism and synesthesia.
Synesthesia can be thought of as a crossing of the senses, where one perceptual experience is accompanied by another unrelated one. For example, individuals with sound-color synesthesia experience visions and sensations of color in harmony with hearing music. In a similar (and the most common) rendition, grapheme-color, letters and numbers are perceived as having their own unique shade.
While at first seemingly unrelated, if you look closer at what is happening in the brain in both autism and synesthesia this overlap is not so surprising. Each condition is thought to at least partly stem from abnormalities in the way the brain is wired.  For example, white matter tracts connecting different parts of the brain – shooting signals across regions and hemispheres – have been shown to be increased in both conditions.
While some of these connections traverse the entire brain, traveling from the frontal cortex back to the occipital lobe, others work more locally, connecting adjacent regions and sending information quickly back and forth. In autism, there is an increased volume of these short-distance white matter connections, either due to a proliferation of synaptogenesis (the creation of new connections), or a failure in the pruning out of these synaptic connections during childhood. Individuals with synesthesia also show a greater density of white matter, particularly in sensory regions implicated in the condition. In individuals with grapheme-color synesthesia, for instance, there is greater connection between visual area four, the region responsible for color perception, and the eponymous visual word-form area.
It has also been suggested that this increased white matter integrity and synesthetic ability may be behind the extraordinary faculty of individuals like Daniel who show signs of autistic savantism. One theory that has been proposed is that synesthesia may help people to better recall memories as they can tap into an automatic mnemonic device via their multiple sensory experiences – i.e. being able to rely on both visual and numeric memory when trying to remember a string of numbers.
However, while there is already an established link between autism and savantism, no such studies have been conducted on superior memory in people with synesthesia. Also, it should be noted that many savants do not report any presence of synesthesia, and certainly there are many synesthetes without any hint of superior memory or savantism. In fact, even I have traces of synesthesia, experiencing sensations of color in combination with days of the week, and I’ve certainly yet to experience any hint of enhanced cognitive ability.
So it looks like Daniel Tammet’s crown as the European champion for reciting Pi is safe for now. And certainly his method is unique – the current world leader, Chinese student Lu Chao, recited 67,890 digits of the number relying solely on ancient Chinese rote memorization techniques.