Author Archives: Attention to the Unseen

Neanderthals and the dead

The New York Times reports: Early in the 20th century, two brothers discovered a nearly complete Neanderthal skeleton in a pit inside a cave at La Chapelle-aux-Saints, in southwestern France. The discovery raised the possibility that these evolutionary relatives of ours intentionally buried their dead — at least 50,000 years ago, before the arrival of anatomically modern humans in Europe.

These and at least 40 subsequent discoveries, a few as far from Europe as Israel and Iraq, appeared to suggest that Neanderthals, long thought of as brutish cave dwellers, actually had complex funeral practices. Yet a significant number of researchers have since objected that the burials were misinterpreted, and might not represent any advance in cognitive and symbolic behavior.

Now an international team of scientists is reporting that a 13-year re-examination of the burials at La Chapelle-aux-Saints supports the earlier claims that the burials were intentional.

The researchers — archaeologists, geologists and paleoanthropologists — not only studied the skeleton from the original excavations, but found more Neanderthal remains, from two children and an adult. They also studied the bones of other animals in the cave, mainly bison and reindeer, and the geology of the burial pits.

The findings, in this week’s issue of Proceedings of the National Academy of Sciences, “buttress claims for complex symbolic behavior among Western European Neanderthals,” the scientists reported.

William Rendu, the paper’s lead author and a researcher at the Center for International Research in the Humanities and Social Sciences in New York, said in an interview that the geology of the burial pits “cannot be explained by natural events” and that “there is no sign of weathering and scavenging by animals,” which means the bodies were covered soon after death.

“While we cannot know if this practice was part of a ritual or merely pragmatic,” Dr. Rendu said in a statement issued by New York University, “the discovery reduces the behavioral distance between them and us.” [Continue reading…]

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The society of microbes that make us what we are

Earth Island Journal: In your new book, Cooked, you explore the art of cooking through the elements of Fire, Water, Air, and Earth. I’m sure you love all your children equally, but of those four, which taught you the most?

Michael Pollan: Fermentation – without a doubt. I began this education about microbiology. I’ve always been interested in nature and other species, and this symbiotic relationship we have with them, and I have mostly paid attention to it in the plant world. I just had no idea of how rich our engagement with microbes was, and how invisible it is to us. I began it when I was doing the Air section and learning about sourdough cultures. But then I got into that last chapter and started learning about fermentation: how much of our food is fermented, the fact that you could cook without the use of any heat, and the fact that we are dependent on these microbes. They’re using us; we’re using them. For me that was most fascinating.

You point out that our feelings about microbes are an expression of our attitude toward the natural world.

Yeah, and our drive for control, at all costs. Microbes are frightening for a couple reasons. One is, they’re invisible. They’re an unseen enemy. And they are pathogens, I mean some of them. You know, conquering infectious disease was a tremendous achievement for our civilization. But as so often happens, we cast things in black and white. So microbes are all bad because some microbes cause disease, and we fail to realize how dependent we are on them for our health. I think we’re going to get to a point where we will discover the unit in evolution and natural selection is not the species as an individual, but what is called the “holobiont,” the group of species that travel together. And that’s what selection is acting on very often, is the super-organism of humans or cats or plants.

Plants, you know, they, too, have their own microbiome; I didn’t talk about this in the piece, but their microbiome is outside their bodies. It surrounds their roots. It’s in what’s called the rhizosphere. There’s a little ecosystem around the root of every plant, and I think we’re going to come to learn that it’s as important to plant health as our flora is to us. I think we’re going to start looking at all species as collectivities, and microbes will be the part of that. And that changes a lot. It changes how you approach agriculture. It certainly changes how you approach health. So I think we’re really on the verge of a paradigm shift around that. [Continue reading…]

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The misleading metaphor of the selfish gene

David Dobbs writes: A couple of years ago, at a massive conference of neuroscientists — 35,000 attendees, scores of sessions going at any given time — I wandered into a talk that I thought would be about consciousness but proved (wrong room) to be about grasshoppers and locusts. At the front of the room, a bug-obsessed neuroscientist named Steve Rogers was describing these two creatures — one elegant, modest, and well-mannered, the other a soccer hooligan.

The grasshopper, he noted, sports long legs and wings, walks low and slow, and dines discreetly in solitude. The locust scurries hurriedly and hoggishly on short, crooked legs and joins hungrily with others to form swarms that darken the sky and descend to chew the farmer’s fields bare.

Related, yes, just as grasshoppers and crickets are. But even someone as insect-ignorant as I could see that the hopper and the locust were wildly different animals — different species, doubtless, possibly different genera. So I was quite amazed when Rogers told us that grasshopper and locust are in fact the same species, even the same animal, and that, as Jekyll is Hyde, one can morph into the other at alarmingly short notice.

Not all grasshopper species, he explained (there are some 11,000), possess this morphing power; some always remain grasshoppers. But every locust was, and technically still is, a grasshopper — not a different species or subspecies, but a sort of hopper gone mad. If faced with clues that food might be scarce, such as hunger or crowding, certain grasshopper species can transform within days or even hours from their solitudinous hopper states to become part of a maniacally social locust scourge. They can also return quickly to their original form.

In the most infamous species, Schistocerca gregaria, the desert locust of Africa, the Middle East and Asia, these phase changes (as this morphing process is called) occur when crowding spurs a temporary spike in serotonin levels, which causes changes in gene expression so widespread and powerful they alter not just the hopper’s behaviour but its appearance and form. Legs and wings shrink. Subtle camo colouring turns conspicuously garish. The brain grows to manage the animal’s newly complicated social world, which includes the fact that, if a locust moves too slowly amid its million cousins, the cousins directly behind might eat it.

How does this happen? Does something happen to their genes? Yes, but — and here was the point of Rogers’s talk — their genes don’t actually change. That is, they don’t mutate or in any way alter the genetic sequence or DNA. Nothing gets rewritten. Instead, this bug’s DNA — the genetic book with millions of letters that form the instructions for building and operating a grasshopper — gets reread so that the very same book becomes the instructions for operating a locust. Even as one animal becomes the other, as Jekyll becomes Hyde, its genome stays unchanged. Same genome, same individual, but, I think we can all agree, quite a different beast.

Why?

Transforming the hopper is gene expression — a change in how the hopper’s genes are ‘expressed’, or read out. Gene expression is what makes a gene meaningful, and it’s vital for distinguishing one species from another. We humans, for instance, share more than half our genomes with flatworms; about 60 per cent with fruit flies and chickens; 80 per cent with cows; and 99 per cent with chimps. Those genetic distinctions aren’t enough to create all our differences from those animals — what biologists call our particular phenotype, which is essentially the recognisable thing a genotype builds. This means that we are human, rather than wormlike, flylike, chickenlike, feline, bovine, or excessively simian, less because we carry different genes from those other species than because our cells read differently our remarkably similar genomes as we develop from zygote to adult. The writing varies — but hardly as much as the reading.

This raises a question: if merely reading a genome differently can change organisms so wildly, why bother rewriting the genome to evolve? How vital, really, are actual changes in the genetic code? Do we even need DNA changes to adapt to new environments? Is the importance of the gene as the driver of evolution being overplayed?

You’ve probably noticed that these questions are not gracing the cover of Time or haunting Oprah, Letterman, or even TED talks. Yet for more than two decades they have been stirring a heated argument among geneticists and evolutionary theorists. As evidence of the power of rapid gene expression mounts, these questions might (or might not, for pesky reasons we’ll get to) begin to change not only mainstream evolutionary theory but our more everyday understanding of evolution. [Continue reading…]

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It’s not just the genes

Eric E. Schadt writes: It’s been 10 years since an international consortium of scientists successfully completed the mapping of the human genome — a world-changing project that couldn’t have happened without public and private support. The feat neatly coincided with the 50th anniversary of the description of DNA’s double helix by Nobel laureates James Watson and Francis Crick. These are incredible achievements, and today, we couldn’t conceive of the future of medicine without them.

Equally unfathomable is a view of medicine that doesn’t take into account the trove of clinically relevant information available for any individual person, and for all people more generally. DNA holds (among other things) your personal architectural blueprint, but unto itself, it is a fairly static factor, the genome in your normal, healthy cells changing very little over the course of your life. We know with certainty that DNA alone is not a categorical predictor of disease. The BRCA1 or BRCA2 gene mutation, for example, signals significantly higher risk for breast cancer in women, but people with the same defective gene often have remarkably different outcomes. Researchers and the public are asking: why is that?

Whether disease manifests, the age at which it manifests, and how severe it becomes, all depend on a multitude of other factors and the dynamic interplay between them: RNA, metabolites, proteins, healthy and diseased tissues, insulin and cholesterol levels, weight, age, gender, tobacco use, and toxic exposures — to name just a few. To achieve a comprehensive understanding of disease so that we can better diagnose and treat it, researchers must examine a hierarchy of levels — multiple scales — of all observable characteristics. Each element — from molecules, to cells, to tissues, to organs, to the person, and then to the community at large — and the flow of information between these elements, is a biological data point at a particular point in time, and the observation of many millions of these elements in a given individual and population of time is where “big data” meets medicine. [Continue reading…]

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Baffling 400,000-year-old clue to human origins

The New York Times reports: Scientists have found the oldest DNA evidence yet of humans’ biological history. But instead of neatly clarifying human evolution, the finding is adding new mysteries.

In a paper in the journal Nature, scientists reported Wednesday that they had retrieved ancient human DNA from a fossil dating back about 400,000 years, shattering the previous record of 100,000 years.

The fossil, a thigh bone found in Spain, had previously seemed to many experts to belong to a forerunner of Neanderthals. But its DNA tells a very different story. It most closely resembles DNA from an enigmatic lineage of humans known as Denisovans. Until now, Denisovans were known only from DNA retrieved from 80,000-year-old remains in Siberia, 4,000 miles east of where the new DNA was found.

The mismatch between the anatomical and genetic evidence surprised the scientists, who are now rethinking human evolution over the past few hundred thousand years. It is possible, for example, that there are many extinct human populations that scientists have yet to discover. They might have interbred, swapping DNA. Scientists hope that further studies of extremely ancient human DNA will clarify the mystery.

“Right now, we’ve basically generated a big question mark,” said Matthias Meyer, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and a co-author of the new study. [Continue reading…]

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Music: Abdullah Ibrahim & Ekaya — ‘The Mountain Of The Night’ & ‘Mannenberg’

He is a jazz visionary and a piano master inspired by America’s legendary composer and pianist Duke Ellington. So, any other adjective I can add about the music of the gifted South African pianist, flutist, composer and bandleader Abdullah Ibrahim would be redundant. His inspiring music was one of the driving forces behind the anti-Apartheid movement in South Africa.

Ibrahim, also known as “Dollar Brand”, was a strong opponent of the apartheid regime. He was arrested several times, but before leaving South Africa for exile, he wrote and recorded his masterpiece: “Mannenberg”. The song became a stirring vamp and the anthem of the anti-apartheid movement following the Soweto uprising in June 1976.

His music inspired then-imprisoned African National Congress (ANC) leader Nelson Mandela. All types of music were banned in jails, but a lawyer for Mandela managed to smuggle some of Ibrahim’s music inside the prison prison and played it in the control room.

“Judy smuggled in Mannenberg,” recalls Ibrahim in an interview with VOA’s Jazz Beat. “When President Mandela heard this song, he said liberation is near.”

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Slow-motion world for small animals

chipmunk

BBC News reports: Smaller animals tend to perceive time as if it is passing in slow motion, a new study has shown.

This means that they can observe movement on a finer timescale than bigger creatures, allowing them to escape from larger predators.

Insects and small birds, for example, can see more information in one second than a larger animal such as an elephant.

The work is published in the journal Animal Behaviour.

“The ability to perceive time on very small scales may be the difference between life and death for fast-moving organisms such as predators and their prey,” said lead author Kevin Healy, at Trinity College Dublin (TCD), Ireland.

The reverse was found in bigger animals, which may miss things that smaller creatures can rapidly spot. [Continue reading…]

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