DNA evidence reveals that the people who civilized Europe were migrants

The New York Times reports: Before the rise of agriculture, Europe was home to a population of hunter-gatherers. Then a wave of people arrived whose DNA resembles that of people in the Near East. It’s likely that they brought agriculture with them.

Finally, about 4,500 years ago, a nomadic population from the steppes of Russia, known as the Yamnaya, swept into Europe.

The analyses that revealed these migrations were based on dozens of ancient European genomes. But in a study published Monday in Nature, David Reich, a geneticist at Harvard Medical School, and his colleagues analyzed the genomes of 230 people who lived between 8,500 and 2,300 years ago.

The enormous sample size has provided enough data to track individual genetic variations as they become more or less common through the history of ancient Europe.

The remains that Dr. Reich and his colleagues analyzed DNA from span the entire continent of Europe. They also include the Yamnaya as well as 21 people who lived in a region of Turkey called Anatolia 8,500 years ago. The study marks the first time scientists have been able to analyze the DNA of the people who brought farming to Europe. [Continue reading…]


How the Western diet has derailed our evolution

Moises Velesquez-Manoff writes: For the microbiologist Justin Sonnenburg, that career-defining moment — the discovery that changed the trajectory of his research, inspiring him to study how diet and native microbes shape our risk for disease — came from a village in the African hinterlands.

A group of Italian microbiologists had compared the intestinal microbes of young villagers in Burkina Faso with those of children in Florence, Italy. The villagers, who subsisted on a diet of mostly millet and sorghum, harbored far more microbial diversity than the Florentines, who ate a variant of the refined, Western diet. Where the Florentine microbial community was adapted to protein, fats, and simple sugars, the Burkina Faso microbiome was oriented toward degrading the complex plant carbohydrates we call fiber.

Scientists suspect our intestinal community of microbes, the human microbiota, calibrates our immune and metabolic function, and that its corruption or depletion can increase the risk of chronic diseases, ranging from asthma to obesity. One might think that if we coevolved with our microbes, they’d be more or less the same in healthy humans everywhere. But that’s not what the scientists observed. [Continue reading…]


Why we think the very first farmers were small groups with property rights

By Elizabeth Gallagher, UCL

For 95% of the history of modern humans we were exclusively hunter gatherers. Then suddenly about 12,000 years ago, something happened that revolutionised the way humans lived and enabled the complex societies we have today: farming.

But what triggered this revolution? Understanding this is incredibly challenging – because this occurred so far in the past, there are many factors to consider. However, by simulating the past using a complex computational model, we found that the switch from foraging to farming most likely began with very small groups of people that were using the concept of property rights.

Farming: an unlikely choice

It may seem obvious why we switched from foraging to farming: it made it possible to stay in one place, feed larger populations, have greater food security and build increasingly complex societies, political structures, economies and technologies. However, these advantages took time to develop and our early farmer ancestors would not have seen these coming.

Indeed, archaeological research suggests that when farming began it was not a particularly attractive lifestyle. It involved more work, a decrease in the quality of nutrition and health, an increase in disease and infection, and greater challenges in defending resources. For a hunter-gatherer at the cusp of the “agricultural revolution”, a switch to farming wasn’t the obvious choice.

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The strange persistence of first languages

Julie Sedivy writes: Like a household that welcomes a new child, a single mind can’t admit a new language without some impact on other languages already residing there. Languages can co-exist, but they tussle, as do siblings, over mental resources and attention. When a bilingual person tries to articulate a thought in one language, words and grammatical structures from the other language often clamor in the background, jostling for attention. The subconscious effort of suppressing this competition can slow the retrieval of words—and if the background language elbows its way to the forefront, the speaker may resort to code-switching, plunking down a word from one language into the sentence frame of another.

Meanwhile, the weaker language is more likely to become swamped; when resources are scarce, as they are during mental exhaustion, the disadvantaged language may become nearly impossible to summon. Over time, neglecting an earlier language makes it harder and harder for it to compete for access.

According to a 2004 survey conducted in the Los Angeles metropolitan area, fewer than half of people belonging to Generation 1.5 — immigrants who arrive before their teenage years — claimed to speak the language they were born into “very well.” A 2006 study of immigrant languages in Southern California forecast that even among Mexican Americans, the slowest group to assimilate within Southern California, new arrivals would live to hear only 5 out of every 100 of their great-grandchildren speak fluent Spanish.

When a childhood language decays, so does the ability to reach far back into your own private history. Language is memory’s receptacle. It has Proustian powers. Just as smells are known to trigger vivid memories of past experiences, language is so entangled with our experiences that inhabiting a specific language helps surface submerged events or interactions that are associated with it. [Continue reading…]


In a society where everyone is ready to defend the common good, corruption doesn’t pay

Suzanne Sadedin writes: By making a few alterations to the composition of the justice system, corrupt societies could be made to transition to a state called ‘righteousness’. In righteous societies, police were not a separate, elite order. They were everybody. When virtually all of society stood ready to defend the common good, corruption didn’t pay.

Among honeybees and several ant species, this seems to be the status quo: all the workers police one another, making corruption an unappealing choice. In fact, the study showed that even if power inequalities later re-appeared, corruption would not return. The righteous community was extraordinarily stable.

Not all societies could make the transition. But those that did would reap the benefits of true, lasting harmony. An early tribe that made the transition to righteousness might out-compete more corrupt rivals, allowing righteousness to spread throughout the species. Such tribal selection is uncommon among animals other than eusocial insects, but many researchers think it could have played a role in human evolution. Hunter-gatherer societies commonly tend toward egalitarianism, with social norms enforced by the whole group rather than any specially empowered individuals. [Continue reading…]


How politics shaped general relativity

David Kaiser writes: The turmoil and disruptions of World War I … prevented many people from learning and thinking about general relativity. The theory’s earliest converts included a Russian mathematician being held in a German prisoner-of-war camp, who was unable to enlighten his Russian colleagues for several years; a German astronomer being held in a Russian prisoner-of-war camp, who was unable to complete his test of one of the theory’s key predictions; and another German astronomer, who passed the time while serving in the German Army by finding the first exact solutions to Einstein’s equations, only to succumb to a deadly disease on the Russian front a few weeks later.

The war also controlled how Einstein’s work spread westward. Because he was a German civil servant, neither Einstein nor his letters — nor even German scientific journals — could cross the English Channel amid the naval blockade. Einstein could, however, travel to neutral countries, like the Netherlands. He made frequent trips to Leiden, where he befriended the great mathematical physicist Willem de Sitter and tutored him in general relativity. And de Sitter, in turn, sent a series of detailed primers on Einstein’s work to a Cambridge colleague, the physicist and astronomer Arthur Eddington.

Eddington, a Quaker and conscientious objector, was concerned that wartime resentments were damaging the international scientific community. He leapt on Einstein’s relativity as a means of restoring harmony. As the historian Matthew Stanley has documented, Eddington’s superiors in London and Cambridge lobbied British government officials to let him devote his mandatory wartime service to preparing an astronomical expedition to test one of Einstein’s major predictions, that gravity could bend the path of starlight. By leading a British team to test the work of a German physicist, Eddington hoped to “heal the wounds of war.” [Continue reading…]


Linguistic diversity in the U.S: 320 languages spoken; 1 in 5 Americans don’t speak English at home

Quartz reports: Every year, the US Census Bureau releases data on the languages spoken in American homes. Usually it groups the languages in 39 major categories. Now it has released much more detailed figures, which show that Americans speak not 39, but more than 320 distinct languages.

The bureau collected the data from 2009 to 2013 as part of the American Community Survey, which asks Americans all kinds of questions to create highly granular estimates on various demographic indicators. The new data estimate that more than 60 million Americans speak a language other than English at home.

Included are 150 Native American languages, as well as relatively obscure ones like Pennsylvania Dutch, Icelandic, Mongolian, and many others. The data estimate that Sudanese, for example, is spoken at home by only 35 Americans. Patwin, spoken by a group of Americans native to northern California, it estimates at just four speakers. [Continue reading…]

There are some anomalies in the data presented here — such as the 12,320 speakers of “African.” That should say: African, not further specified.


The third dimension: Why Amazon just opened a bookstore

In all honesty, I don’t know why Amazon just opened a physical bookstore in Seattle.

Maybe they want to drive the last remaining independent bookstores out of business by stealing their employees. Maybe it’s a memorial to commemorate the form of brick-and-mortar retail the online corporation has been so successful in destroying — a nostalgic return designed to remind customers of its own obsolesce.

On the other hand, this could be a semi-conscious token recognition that online is not in all ways expansive. It’s not just bigger, faster, cheaper, better.

The price of using a screen is that through its surface we step away from three-dimensional space.

Although the physical internet exists in three-dimensional space, we can only connect through a two-dimensional display.

Even though the tool for navigating through digital space has traditionally been called a browser, a screen marshals attention in ways that physical browsing does not.

Wandering around a bookstore, scanning titles along bookshelves and leafing through pages, are physical actions that can only take place in physical space. And that space has fuzzy boundaries.

When we examine a book in our hands, we can feel its weight, see the font style and size, the quality of the binding, open pages at random and engage with this physical object in a much richer and more complex way than through a digital window.

This physicality points to an even more basic disjunction between corporeal existence and digital activity.

However entwined our lives have become with electronic devices, we remain creatures confined at any one moment to one place in the universe.

Increasingly, however, our lives are disconnected from where we are. People come together and then their phones step between them.

We are forever being beckoned to be some place else.

The end of all our exploring may never come if we fail to return where we started.


The human mind as the preeminent scientific instrument

Walter Isaacson writes: This month marks the 100th anniversary of the General Theory of Relativity, the most beautiful theory in the history of science, and in its honor we should take a moment to celebrate the visualized “thought experiments” that were the navigation lights guiding Albert Einstein to his brilliant creation. Einstein relished what he called Gedankenexperimente, ideas that he twirled around in his head rather than in a lab. That’s what teachers call daydreaming, but if you’re Einstein you get to call them Gedankenexperimente.

As these thought experiments remind us, creativity is based on imagination. If we hope to inspire kids to love science, we need to do more than drill them in math and memorized formulas. We should stimulate their minds’ eyes as well. Even let them daydream.

Einstein’s first great thought experiment came when he was about 16. He had run away from his school in Germany, which he hated because it emphasized rote learning rather than visual imagination, and enrolled in a Swiss village school based on the educational philosophy of Johann Heinrich Pestalozzi, who believed in encouraging students to visualize concepts. While there, Einstein tried to picture what it would be like to travel so fast that you caught up with a light beam. If he rode alongside it, he later wrote, “I should observe such a beam of light as an electromagnetic field at rest.” In other words, the wave would seem stationary. But this was not possible according to Maxwell’s equations, which describe the motion and oscillation of electromagnetic fields.

The conflict between his thought experiment and Maxwell’s equations caused Einstein “psychic tension,” he later recalled, and he wandered around nervously, his palms sweating. Some of us can recall what made our palms sweaty as teenagers, and those thoughts didn’t involve Maxwell’s equations. But that’s because we were probably performing less elevated thought experiments. [Continue reading…]


Will quantum mechanics swallow relativity?

Corey S Powell writes: It is the biggest of problems, it is the smallest of problems.

At present physicists have two separate rulebooks explaining how nature works. There is general relativity, which beautifully accounts for gravity and all of the things it dominates: orbiting planets, colliding galaxies, the dynamics of the expanding universe as a whole. That’s big. Then there is quantum mechanics, which handles the other three forces — electromagnetism and the two nuclear forces. Quantum theory is extremely adept at describing what happens when a uranium atom decays, or when individual particles of light hit a solar cell. That’s small.

Now for the problem: Relativity and quantum mechanics are fundamentally different theories that have different formulations. It is not just a matter of scientific terminology; it is a clash of genuinely incompatible descriptions of reality.

The conflict between the two halves of physics has been brewing for more than a century — sparked by a pair of 1905 papers by Einstein, one outlining relativity and the other introducing the quantum — but recently it has entered an intriguing, unpredictable new phase. Two notable physicists have staked out extreme positions in their camps, conducting experiments that could finally settle which approach is paramount. [Continue reading…]


How did complex creatures evolve from simple single-celled organisms?

Emily Singer writes: In September 2014, Christa Schleper embarked on an unusual hunting expedition in Slovenia. Instead of seeking the standard quarry of deer or wild boar, Schleper was in search of Lokiarchaeota, or Loki, a newly discovered group of organisms first identified near deep-sea vents off the coast of Norway. The simple, single-celled creatures have captured scientists’ interest because they are unlike any other organism known to science. They belong to an ancient group of creatures known as archaea, but they seem to share some features with more complex life-forms, including us.

Though little is known about Loki, scientists hope that it will help to resolve one of biology’s biggest mysteries: how life transformed from simple single-celled organisms to the menagerie of complex life known as eukaryotes — a category that includes everything from yeast to azaleas to elephants. “Next to the origins of life, there’s probably no bigger mystery in the history of life,” said John Archibald, an evolutionary biologist at Dalhousie University in Nova Scotia.

The jump from single cells to complex creatures is so puzzling because it represents an enormous evolutionary gulf. “How do you make a eukaryote, that’s a big question,” said Schleper, a microbiologist at the University of Vienna in Austria. “It’s a huge transition.”

Though single-celled organisms blanket the Earth and are capable of impressive biochemistry — some can eat nuclear waste, for example — their structure and shape remain simple. Cells from animals, plants and fungi, which make up the eukaryotes, are much more sophisticated. They possess a suite of features lacking in their simpler brethren: a nucleus that houses DNA; an energy-producing device known as the mitochondrion; and molecular architecture, known as the cytoskeleton, that controls cell shape and movement.

Most biologists agree that at some point around two billion years ago, one featureless cell swallowed another, and the two began to work together as one. But the details of this process — whether this symbiosis jump-started an evolutionary process, or whether it happened midway along the path to eukaryotes — continue to drive huge disputes in the field. [Continue reading…]


The theory of parallel universes is not just maths – it is science that can be tested

By Eugene Lim, King’s College London

The existence of parallel universes may seem like something cooked up by science fiction writers, with little relevance to modern theoretical physics. But the idea that we live in a “multiverse” made up of an infinite number of parallel universes has long been considered a scientific possibility – although it is still a matter of vigorous debate among physicists. The race is now on to find a way to test the theory, including searching the sky for signs of collisions with other universes.

It is important to keep in mind that the multiverse view is not actually a theory, it is rather a consequence of our current understanding of theoretical physics. This distinction is crucial. We have not waved our hands and said: “Let there be a multiverse”. Instead the idea that the universe is perhaps one of infinitely many is derived from current theories like quantum mechanics and string theory.

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Science is a dynamic, ongoing reconfiguration of knowledge and must be free to change

David P Barash writes: Coming from a scientist, this sounds smug, but here it is: science is one of humanity’s most noble and successful endeavours, and our best way to learn how the world works. We know more than ever about our own bodies, the biosphere, the planet and even the cosmos. We take pictures of Pluto, unravel quantum mechanics, synthesise complex chemicals and can peer into (as well as manipulate) the workings of DNA, not to mention our brains and, increasingly, even our diseases.

Sometimes science’s very success causes trouble, it’s true. Nuclear weapons – perhaps the most immediate threat to life on Earth – were a triumph for science. Then there are the paradoxical downsides of modern medicine, notably overpopulation, plus the environmental destruction that science has unwittingly promoted. But these are not the cause of the crisis faced by science today. Today science faces a crisis of legitimacy which is entirely centred on rampant public distrust and disavowal.

A survey by the Pew Research Center in Washington, DC, conducted with the American Association for the Advancement of Science, reported that in 2015 a mere 33 per cent of the American public accepted evolution. A standard line from – mostly Republican – politicians when asked about climate change is ‘I’m not a scientist’… as though that absolved them from looking at the facts. Vaccines have been among medical science’s most notable achievements (essentially eradicating smallpox and nearly eliminating polio, among other infectious scourges) but the anti-vaccination movement has stalled comparable progress against measles and pertussis.

How can this be? Why must we scientists struggle to defend and promote our greatest achievements? There are many possible factors at work. In some cases, science conflicts with religious belief, particularly among fundamentalists – every year I find it necessary to give my undergraduate students a ‘talk’ in which I am frank that evolutionary science is likely to challenge any literalist religious beliefs they might have. In the political sphere, there is a conflict between scientific facts and short-term economic prospects (climate‑change deniers tend to be not merely scientifically illiterate, but funded by CO2-emitting corporations). Anti-vaxxers are propelled by the lingering effect of a single discredited research report that continues to resonate with people predisposed to ‘alternative medicine’ and stubborn opposition to establishment wisdom. [Continue reading…]


Competition in Cambrian seas 542 million years ago helped cause an explosion in animal diversity

Brooke Borel writes: Battles fought 542 million years before today helped fuel a blast that brought humans and most animals into existence. The great Cambrian Explosion was a period of unprecedented one-upmanship. Beastly claws crushed through thin skin, and soft-bodied creatures evolved shells shaped like scythes, sickles, and shields.

For about a billion years prior, the cells and genes that would later create animals were evolving in microscopic organisms who inhabited the oceans of Earth. These essential molecular changes may only be inferred today because they’re not preserved in fossils. The earliest traces of animals, about 580 million years old, appear soft, with no sign of claws, teeth, limbs, or brains. Then, within 54 million years (a relative blink but still, 270 times the duration of humans’ existence thus far), most of the main animal groups around today originated. This rapid rate of increase in animal architectures has never since been repeated.

A simple species count does not do justice to the power of the Cambrian Explosion. Species have continuously formed over time. A new type of moth may have antennae that are furrier than its sisters; a new species of dinosaur may be distinguished by clawed wings and vicious front fangs. But a new phylum — a major branch on the tree of life, the upper-level ranking that separates an insect from a pterodactyl — is rarely born.

Most of today’s 30 to 40 animal phyla originated in the Cambrian, and have persisted through time with hundreds of variations on a theme. [Continue reading…]


Sino-Tibetan populations shed light on human cooperation

By Ruth Mace, UCL

One of the big questions in anthropology is why humans, unlike most animals, cooperate with those we are not closely related to. Exactly what has driven this behaviour is not well understood. Anthropologists suspect it could be down to the fact that women have usually left their homes after marriage to go and live with their husband’s family. This creates links between distant families, which may explain our tendency to cooperate beyond our own households.

Now our study on the Tibetan borderlands of China, published in Nature Communications, shows that it is indeed the case that cooperation is greater in populations where females disperse for marriage.

A natural experiment in social structure

There are a lot of different theories about the link between dispersal, kinship and cooperation, which is what we wanted to test. Anthropologists believe that dispersal leads to cooperation through links between families, and some evolutionary models predict that when nobody moves this leads to residents competing for the same resources and greater conflict between kin. But there are also models that suggest the opposite is true – that if nobody moves, neighbours are more likely to be related, leading to more cooperation in the neighbourhood.

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