There is a really interesting article on the Scientific American website about synesthesia, where the experiences of different experiences intermingle into a single combined experience. People can taste colours or hear shapes, for example.

New born infants have synesthetic experiences, until they learn to separate their perception of the sensory inputs. Designing experiments to test this hypothesis is difficult, which is why the hypothesis has remained untested for twenty years.

This is what the psychologists did:

“Researchers presented infants and adults with images of repeating shapes (either circles or triangles) on a split-color background: one side was red or blue, and the other side was yellow or green. If the infants had shape-color asso­ciations, the scientists hypoth­esized, the shapes would affect their color preferences. For in­stance, some infants might look significantly longer at a green back­ground with circles than at the same green background with triangles. Absent synesthesia, no such dif­ference would be visible.

The study confirmed this hunch. Infants who were two and three months old showed significant shape-color associations. By eight months the preference was no longer pronounced, and in adults it was gone altogether.”

Reading Steven Mithen’s work, (see this earlier post)  I wondered if it were possible that Neanderthals might be synesthetes. I hinted as much in Flow, where Zana experiences  synesthetic blending as she goes into a trance-like state.

I have just discovered Mike William’s absorbing book entitled ‘Prehistoric Belief’. I think it is unusual and rather special. It is well written and beautifully illustrated and this makes it special. The author has taken many hours to ensure that everything is just right. It’s attention to detail is spot on, as only a professional archaeologist can achieve. Scholarly, and in tune with modern thinking, there is one more thing that makes it special.

A lot of modern scholarship on religions reduce them to a series of social processes. Scott Atran’s work, for example, as stimulating as it is, reduces religion to ‘a community’s costly and hard-to-fake commitment to a counter-factual and counter-intuitive world of supernatural agents which master people’s existential anxieties, such as death or deception.’

The power and limitations of this statement lie in its reductionism: because it can apply to each and every religion, the content of any one religion becomes of little consequence. All religions are the same as long as they are costly, counter-intuitive and counter-factual.

Mike Williams takes a different stance: he is interested enough to undergo similar experiences to the early shamans to explore their ‘internal worlds’, to look for their ‘gods’. In doing so, he has gained a real respect and affection for these primitive (or lost) ways of thinking.

It is the combination of the academic and the experiential that makes this book unusual and rather special. If any of the above has intrigued you, then please read Mike’s book for yourselves. Read Mike’s blog here.

A remarkable talk: clear and exciting in its potential.

Peter Parham and Laurent Abi-Rached’s paper in Science on the movement of human leukocyte antigen system (HLA) genes from Neanderthals and Denisovans into modern humans has certainly caught a lot of press attention. The Observer newspaper carried an editorial, predicatably entitled, Neanderthals: a bit of rough.

The companion Guardian newspaper had a thoughtful article about the downsides of this genetic introgression.

Natural selection acts of individuals, and for the Neanderthals and early modern humans the life expectancy was quite short. Genes that have a beneficial effect in the short term can be selected, even though they may have harmful effects in later life. This is because it is young people who make babies and pass their genes on. Genes that have harmful effects in children are much rarer than those that have harmful effects in middle and old age. This is a well understood effect and explains why genes that pre-dispose middle aged people to cancers are relatively common.

It is thought that some of the HLA genes passed into the human genome might lead to boosted immunity and also to autoimmune diseases, such as multiple sclerosis, psoriasis, rheumatism and eczema.

The Guardian article puts it like this:

“Paul Norman, a co-author on the paper, put it like this: “There’s enormous genetic variation in people’s immune systems and that can control how different people fight different diseases. This could go some way to explaining why some people are better at fighting some infections than others, but we think it also goes some way to explaining why some people are susceptible to autoimmune diseases.”

Autoimmune diseases are conditions that arise when the immune system turns its firepower on the body, usually when it mistakenly identifies the body’s tissues as foreign, and so potentially dangerous.

“The vast majority of autoimmune diseases have been shown by genome-wide association studies to be associated with particular HLA alleles and we find a couple of those in Denisovans,” Norman added. “So it looks to me like modern humans have acquired these alleles, but we weren’t kind of prepared for them, we hadn’t grown up with them, and in some circumstances, they can start to attack us as well as the viruses and other pathogens.”

The group is now investigating a gene variant called HLA-B51, which came from cross-breeding with Neanderthals and has already been linked to Behcet’s disease, a rare and chronic inflammatory condition.

How else might immune genes inherited from Neanderthals and Denisovans affect the health of modern humans? The question is intriguing and will differ from population to population. Here, at least, is a worthy successor to the question of “did we or didn’t we?”

Y chromosome

It was long thought that modern Europeans were directly descended from the early modern human hunter-gatherers that replaced the Neanderthals between 35 000 and 30 000 years ago.

This idea was challenged by a number of researchers (eg Rowley-Conwy), who argued that waves of immigration of neolithic farmers from the middle east effectively replaced the modern humans in Europe.

Today, Busby and his colleagues suggest by an analysis of the genetic variation of male Y chromosomes that the variant known as ‘R-S127′ is so common within modern European males that it most likely became established in Europe well before the arrival the arrival of the neolithic farmers. This supports the original theory, that modern humans can trace tracing their ancestry back to archaic hunter-gatherers.

Given that we now know that the Neanderthals interbred with such people, perhaps there really is a bit of the Neanderthal in all of us, as the press loves to describe it.

Source: BBC

Interesting article in the Daily Telegraph today, entitled ‘Scientists reveal health benefits of breeding with Neanderthals‘. This story broke at a Royal Society conference earlier in the summer. I wrote about it then.

What caught my eye today was the opening paragraph of the Telegraph article:

“Interbreeding between the two species between 65,000 and 90,000 years ago speeded up modern man’s rapid rise to the head of the evolutionary tree, it is claimed.”

The idea of humans being ‘head of the evolutionary tree’ is a popular one, especially amongst over-competitive journalists, but it is not an idea that most evolutionary scholars believe in. Indeed, I remember my University teachers being unequivocal about this. ‘All organisms alive today are survivors of the game of life.’, said dear old Joe Powell. ‘They are all winners. There is no head of the evolutionary tree.’

Personally, I think that humans are an evolutionary cul-de-sac. We are the ‘Johnny-come-latelies’ of evolution, who will burn brightly and then disappear just as quickly. Leaving the planet to the real ‘winners’, the bacteria.

The inhabitants of Easter Island off the coast of Chile became extinct, probably because they chopped down all of their trees to allow the islanders to build bigger and better statues.

(See Diamond, Jared (2005). Collapse. How Societies Choose to Fail or Succeed. New York: Viking. ISBN 0-14-303655-6.)

Easter Islanders got so locked into their own internal games of power and status that they were oblivious to the wider ecological consequences. I suspect we will go extinct in much the same way, whilst we read about it on news blogs and twitter #armageddon.

The article is long, but full of colourful insights. Here is a typical example:

Archaic humans like Homo erectus “spread like many other mammals in the Old World,” Pääbo told me. “They never came to Madagascar, never to Australia. Neither did Neanderthals. It’s only fully modem humans who start this thing of venturing out on the ocean where you don’t see land. Part of that is technology, of course; you have to have ships to do it.

But there is also, I like to think or say, some madness there. You know? How many people must have sailed out and vanished on the Pacific before you found Easter Island? I mean, it’s ridiculous. And why do you do that? Is it for the glory? For immortality? For curiosity? And now we go to Mars. We never stop.”

If the defining characteristic of modem humans is this sort of Faustian restlessness, then, by Pääbo’s account, there must be some sort of Faustian gene. Several times, he told me that he thought it should be possible to identify the basis for this “madness” by comparing Neanderthal and human DNA.

”If we one day will know that some freak mutation made the human insanity and exploration thing possible, it will be amazing to think that it was this little inversion on this chromosome that made all this happen and changed the whole ecosystem of the planet and made us dominate everything,” he said at one point. At another, he said, “We are crazy in some way. What drives it? That I would really like to understand. That would be really, really cool to know.”

Nature 9 August 2011 doi:10.1038/476136a

A wonderful review paper in Nature, reviewing the extraordinary progress of the study of ancient genomics.  The whole paper is worth reading, not least for the cameo role by John Hawks, whose blog has been a support to me in producing this work.

Here are the key points of the paper:

• humans living outside Africa owe up to 4% of their DNA to Neanderthals. One explanation might be that humans migrating out of Africa mated with Neanderthals, probably resident in the Middle East, before their offspring fanned out across Europe and Asia. The date of that interbreeding has now been pinned down to 65,000–90,000 years ago.
• scientists believe humans may have acquired not just DNA from archaic humans, but useful traits too. Human gene variants linked to brain development and speech were once proposed as candidates, only to be discounted after closer inspection of the Neanderthal genome.
• a study presented at a Royal Society symposium in London in June suggests that humans owe important disease-fighting genes (HLA) to Neanderthals and Denisovans (a newly discovered related species). Interbreeding endowed humans with a ‘hybrid vigour’ that helped them colonize the world, said Peter Parham, an immunogeneticist at Stanford University School of Medicine, California.
• John Hawks, a biological anthropologist at the University of Wisconsin-Madison, notes that many HLA genes pre-date humans’ split from Neanderthals and Denisovans, and that the differences may have arisen by chance as the groups evolved.
• Neanderthals lack certain forms of genes that may help modern humans to fend off epidemic diseases, such as measles. This is hardly surprising: the low population density of hunter-gatherers meant that epidemics were unlikely, so they probably would not have benefited from these immune genes.
• Pääbo, Reich and the other scientists involved in sequencing the ancient genomes are eager to see others run with their data, but caution that they need to be aware of the limitations. “They’re really terrible-quality genomes”, chock-full of gaps and errors and sections in which short stretches of DNA sequence have been put in the wrong place, says Reich. “There are a lot of traps in using these data, and if people are not careful they’ll find all sorts of interesting things that are wrong.”

Inuit culture formed a foundation upon which I built the Neanderthal world in ‘Flow’. Zana observes that the world is changing ‘and it is not as cold as it used to be.’ I find this video powerfully sad and strangely prophetic. Thank you, @IshtarsGate for guiding me to it.

The traditional view is that dogs arose from the taming and domestication of young wolves, about 14,000 years ago. A paper in PLOS One questions this date. Nikolai D. Ovodov and his colleagues describe the well-preserved remains of a dog-like canid from the Razboinichya Cave (Altai Mountains of southern Siberia) that dates to 33 000 years ago, well before the last ice age.

Readers of the novel ‘Flow’ will recognise the importance of these early dog-like creatures, as will those interested in mythologies. The origin of Wolf-Kowowai us the stuff of family legend, to be told and re-told around firesides for millenia to come.