The Surprising Gut Microbes of African Hunter-Gatherers

Hadza women cook tubers they’ve foraged throughout the day. Compared to the men, who spend their day hunting game, the women have more gut bacteria for breaking down fibrous veggies.

In Western Tanzania tribes of wandering foragers called Hadza eat a diet of roots, berries, and game. According to a new study, their guts are home to a microbial community unlike anything that’s been seen before in a modern human population — providing, perhaps, a snapshot of what the human gut microbiome looked like before our ancestors figured out how to farm about 12,000 years ago.

“There have been relatively few studies of gut microbiota among humans eating pre-industrial diets, relative to humans eating post-industrial ones,” said Lawrence David, a microbiologist from Duke University, who was not a part of the study. The new study, published today in Nature Communications, is timely and important, David says, because it provides a snapshot of pre-industrial human’s gut microbiota. It also indicates that the ecosystem in our guts adapts not only to our diets but to the environments we live in.

Researchers have known for decades that the biota in our gut vary depending on what we eat. But the Hadza microbiome still turned out to be surprisingly different.

To study the difference between the ancient and modern gut, researchers analyzed stool samples from 16 Italian urbanites and 27 Hadza foragers, of both genders.

The Italians’ gut flora was generally what they expected in Western diets, with some Mediterranean influences. The Hadza’s poop, however, was like stepping into a lost continent of microbe biodiversity. ”The Hadza gut mibrobiome has an entirely unique combination of bacteria from any western population, or rural African population, that’s been sampled,” said co-author Alyssa Crittenden, a nutritional anthropologist from the University of Nevada, Las Vegas.

Many of the bacteria are species that the researchers had never seen before. And even familiar microbes were present in unusual levels in the Hadza belly. “The Hadza not only lack the ‘healthy bacteria,’ and they don’t suffer from the diseases we suffer from, but they also have high levels of bacteria that are associated with disease,” Crittenden said.

Wiggum plots showing the relative abundance and diversity of gut biota from different cultures. The Hadza’s doesn’t just have unexpected amounts of known bacteria, it has many species that have never been observed before.

In westerners, Bifidumbacterium is a microbe that many nutrition scientists thought was essential to good gut health, but it is almost completely absent in the foragers. Likewise, high counts of the bacteria Treponema have been linked to maladies like Crohn’s disease and irritable bowel syndrome. Neither of these diseases exist among the Hadza, but their guts contain abundant Treponema.

Modern humans have only spent 5 percent of our history as farmers. Before that, most of our species were foragers of some type or other. ”Studies like this one are rare opportunities for generating hypotheses about the bacteria that are most sensitive to diet and metabolism in the gut,” said David. The Hadza’s stomachs represent a reference ecosystem for comparing our modern lifestyles.

That’s not to say you should start stocking up on exotic roots, berries, and wild game hoping to create the perfect balance of beneficial bacteria for your belly. Crittenden and her research partners warn against turning their research into a diet, even if the link between the Hadza’s gut microbiome and their lower rates of gastrointetinal illness prove true. “Even if you try to emulate the diet of the Hadza, you’re not living in the environment,” explained Amanda Henry, a dietary ecologist from the Max Planck Institute in Germany, and a co-author of the study. “There are transfers from the soils, from the animals.” In other words, it’s not just what the Hadza eat that contribute to their remarkable gut flora, it’s where and how they are eating it, too.

Read more at Wired Science

Some Monkeys Are (Really) Monogamous

Unlike many humans, some monkeys are genuinely faithful to their mates.

A species known as Azara's owl monkeys tends to be monogamous, according to a new study of these primates. The research also found that the monkeys' inclination to be faithful was related to the male monkeys' tendency to care for their offspring.

"They [Azara's owl monkeys] live in pairs, so, in a group, we have only one adult male and one adult female, and both of them are faithful," study author Maren Huck, a professor at the University of Derby in England, told Live Science.

"We found a link between... parental care and having few instances of cheating," Huck said.

Researchers had known before this study that members of the Azara's species were socially monogamous, which means that males and females live in pairs. But in animals, including humans, social monogamy is not always equivalent to what researchers call genetic monogamy, where females and males only reproduce with their mates.

True genetic monogamy is in fact extremely rare, the researchers said.

One way researchers can check for genetic monogamy is to analyze the DNA of mating pairs, and check the paternity of the offspring. In the study, the researchers analyzed field observations of the monkeys' behavior, along with genetic samples from a total of 128 monkeys, including some that lived in groups, and others that were solitary "floaters." The material used by the research team included samples from 35 offspring that were born to 17 reproducing pairs.

The researchers found that both male and female monkeys in the study were faithful to their mates, and that all the offspring were indeed genetically related to their male parents.

When males care for offspring, it does not necessarily cause their partners to be monogamous, Huck said, and it is hard to say which came first, but the two may reinforce each other.

It's thought that, in general, a male can gain more by caring for his offspring than by trying to find additional mates. This is especially true in species in which females may be hard for males to find, because of the conditions in which the animals dwell.

The new study may lend an insight into the mechanisms behind pair bonding, which does not necessarily go together with monogamy, and parental mechanisms in other species, including humans.

"Pair bonding — love, if you want — is prevalent in all human societies, whereas fathering is much more variable," study author Eduardo Fernandez-Duque, an associate professor of anthropology at the University of Pennsylvania, said in a statement. "The owl monkey story is suggesting that, under very specific ecological settings, this preference for each other leads to the pair spending a lot of time in close proximity, thus facilitating paternal care and increasing paternity certainty. Genetic monogamy is the result."

Read more at Discovery News

Geologic Wonder: See Grand Canyon from Space

Helicopter tours of the Grand Canyon can provide a bird's-eye view of the iconic landmark. But that's nothing compared to what astronauts see as they zip over northern Arizona in the International Space Station.

In a new image taken from orbit, the Grand Canyon is visible slicing through the Kaibab Plateau, which is part of the expansive Colorado Plateau of Arizona, Utah, Colorado and New Mexico. The photograph was taken by the Expedition 39 crew aboard the ISS on March 25, 2014, according to NASA's Earth Observatory.

In the image, the canyon's forested North and South Rims are visible on either side of the canyon. The popular South Rim, which hosts about 90 percent of the Grand Canyon's 5 million visitors a year, averages about 7,000 feet (2,134 meters) in elevation, according to the National Park Service. The remote North Rim is about 1,000 feet (305 m) higher. Its cooler climes mean that roads to the North Rim are closed October through May each year.

Between the two rims, the Grand Canyon plunges a mile (1.6 km) through layers of schist, sandstone, limestone and more. The Colorado River carved the 227-river-mile (446 kilometers) canyon over millions of years as the Colorado Plateau experienced a tectonic uplift. The amount of time it took to carve the Canyon is a matter of major debate. On one side are researchers who see the canyon as "young" — The gorge as it is today is about 6 million years old, carved out by the Colorado River after it changed course some 11 million years ago. But some research points to sections of the canyon dating back 70 million years. Some researchers see these old sections as evidence of the origin of the Grand Canyon, while others argue that they are in fact "paleo-canyons" carved long ago that the Colorado River simply found and flowed into. Others argue that these sections represent the origin of today's canyon. The debate is intensified by gaps in the geological record and recent, complicated tectonic changes in the region.

Read more at Discovery News

Saturn May Have Given Birth to a Baby Moon

NASA’s Saturn-orbiting Cassini spacecraft has imaged something peculiar on the outermost edge of the gas giant’s A-ring. A bright knot, or arc, has been spotted, 20 percent brighter than the surrounding ring material and astronomers are interpreting it as a gravitational disturbance caused by a tiny moon.

“We have not seen anything like this before,” said Carl Murray of Queen Mary University of London. “We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right.”

The feature in the ring’s edge is approximately 750 miles (1,200 kilometers) long and 6 miles (10 kilometers) wide, but the possible baby moon is likely only half a mile across if it’s confirmed to exist. The observation was made on April 15, 2013, using Cassini’s narrow angle camera and the discovery was announced in a paper published today in the journal Icarus.

Saturn’s moons are icy little worlds and many are thought to have been formed through an agglomeration of material from the extensive ring system that surrounds the planet to this day.

Although there’s the exciting possibility of this new object being the birth of a small satellite, it could also be signs of a small overlooked moon that’s in the process of breaking up. But astronomers are hopeful that this might be the first time we’ve witnessed a baby moon in the process of forming in the solar system. The candidate moon is being nicknamed “Peggy.”

“Witnessing the possible birth of a tiny moon is an exciting, unexpected event,” said Cassini Project Scientist Linda Spilker, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Generally, Saturn’s moons get larger the further their orbits from the planet; over the system of satellites’ history, moons likely migrated from close to the planet, scooping up smaller moons as they drifted further away. As a consequence, Saturn’s rings are depleted of moon-forming material, potentially signalling that Peggy will be one of the last moons to form.

Read more at Discovery News

Neanderthals and Cro-magnons did not coexist on the Iberian Peninsula, suggests re-analysis of dating

The meeting between a Neanderthal and one of the first humans, which we used to picture in our minds, did not happen on the Iberian Peninsula.

That is the conclusion reached by an international team of researchers from the Australian National University, Oxford University, the UPV/EHU-University of the Basque Country, University of Maryland, Universitat de Girona and the University of Oviedo, after redoing the dating of the remains in three caves located on the route through the Pyrenees of the first beings of our species: L'Arbreda, Labeko Koba and La Viña.

The paper, entitled "The chronology of the earliest Upper Palaeolithic in northern Iberia: New insights from L'Arbreda, Labeko Koba and La Viña," has been published in the Journal of Human Evolution. Until now, the carbon 14 technique, a radioactive isotope which gradually disappears with the passing of time, has been used to date prehistoric remains.

When about 40,000 years, in other words approximately the period corresponding to the arrival of the first humans in Europe, have elapsed, the portion that remains is so small that it can become easily contaminated and cause the dates to appear more recent. It was from 2005 onwards that a new technique began to be used; it is the one used to purify the collagen in DNA tests.

Using this method, the portion of the original organic material is obtained and all the subsequent contamination is removed. And by using this technique, scientists have been arriving at the same conclusions at key sites across Europe: "We can see that the arrival of our species in Europe took place 8,000 years earlier than what had been thought and we can see the earliest datings of our species and the most recent Neanderthal ones, in which, in a specific regional framework, there is no overlapping," explained Alvaro Arrizabalaga, professor of the department of Geography, Prehistory and Archaeology, and one of the UPV/EHU researchers alongside María-José Iriarte and Aritza Villaluenga.

The three caves chosen for the recently published research are located in Girona (L'Arbreda), Gipuzkoa (Labeko Koba) and Asturias (La Viña); in other words, at the westernmost and easternmost tips of the Pyrenees and it was where the flow of populations and animals between the peninsula and continent took place. "L'Arbreda is on the eastern pass; Labeko Koba, in the Deba valley, is located on the entry corridor through the Western Pyrenees (Arrizabalaga and Iriarte excavated it in a hurry in 1988 before it was destroyed by the building of the Arrasate-Mondragon bypass) and La Viña is of value as a paradigm, since it provides a magnificent sequence of the Upper Palaeolithic, in other words, of the technical and cultural behaviour of the Cro-magnons during the last glaciation," pointed out Arrizabalaga.

The selecting of the remains was very strict allowing only tools made of bones or, in the absence of them, bones bearing clear traces of human activity, as a general rule with butchery marks, in other words, cuts in the areas of the tendons so that the muscle could be removed.

"The Labeko Koba curve is the most consistent of the three, which in turn are the most consistent on the Iberian Peninsula," explained Arrizabalaga. 18 remains were dated at Labeko Koba and the results are totally convergent with respect to their stratigraphic position, in other words, those that appeared at the lowest depths are the oldest ones.

The main conclusion -- "the scene of the meeting between a Neanderthal and a Cro-magnon does not seem to have taken place on the Iberian Peninsula" -- is the same as the one that has been gradually reached over the last three years by different research groups when studying key settlements in Great Britain, Italy, Germany and France.

Read more at Science Daily

Does germ plasm accelerate evolution?

Scientists at The University of Nottingham have published research in the journal Science that challenges a long held belief about the way certain species of vertebrates evolved.

Dr Matt Loose and Dr Andrew Johnson who are experts in genetics and cell development in the School of Life Sciences carried out the research, funded by the Medical Research Council (MRC). It suggests that genes evolve more rapidly in species containing germ plasm. The results came about as they put to the test a novel theory that early developmental events dramatically alter the vertebrate body plan and the way evolution proceeds.

The original theory was proposed by Dr Johnson over 10 years ago. His view is that the relationship between the germ line (hereditary germ cells that create sperm and eggs) and the soma (cells which form the body of an organism) also impacts on species diversity. He argues that once a species evolves a substance called germ plasm, germ cells are independent of other cells, so constraints on somatic development are liberated and this enhances a species' ability to evolve. As a result, he says, vertebrates such as frogs, fruit flies and birds, which look unlike their ancestors, came about, and remarkably they evolved much faster than their ancestors did.

Taking a new look at embryology

Early in animal development a subset of cells in an embryo becomes committed to produce Primordial Germ Cells (PGCs). PGCs develop into sperm or eggs. The remaining cells develop as the soma, a term that describes all of the tissues that make up an individual's body. The germ line is an immortal cell lineage, passed on from generation to generation, and charged solely with producing a new embryo at fertilisation. The soma, on the other hand, dies off in every generation. In the most classic biological sense its job is to interpret the effects of natural selection in order to determine genetic fitness, leading to so called 'survival of the fittest'.

There are two known ways to make a PGC. There is preformation -- material in the egg called germ plasm is inherited directly by a few cells in the embryo, and germ plasm instructs these cells to become PGCs. Alternatively, PGCs can develop without germ plasm. In this case PGCs can be induced to form by signals secreted from other cells, which are part of the soma. This is called epigenesis.

Dr Johnson said: "Biologists are accustomed to thinking about how adult somatic traits impact natural selection and the evolution of new species. What is much less clear is the role of embryological mechanisms in evolution, and how they might contribute to species diversity."

A new computer programme tested their hypothesis In this latest publication Dr Loose put this theory to the test. He said: "To investigate the effect germ plasm has on sequence changes we had to look at as many sequences as possible -- nearly 12 million sequences were analysed and processed from 165 different species including mammals, reptiles, amphibians and fish."

With graduate student Teri Evans, Dr Loose wrote computer programmes to process these sequences and test the hypothesis. They compared DNA sequences from species that contain germ plasm with related species that use epigenesis instead. So, for example, they compared DNA from salamanders (epigenesis) with frogs (germ plasm), both of which are amphibians. Unexpectedly, they found that species with germ plasm have a faster rate of sequence change than those without. Thus, frogs evolve faster than salamanders. Similar comparisons with fish and reptile species identify the same pattern, suggesting it is a generalised feature of animal evolution. These results support the theory that germ plasm provides a selective advantage because it enables more rapid evolution. In addition, they support the view that the relationship between development of the germ line and soma shapes species diversity in the animal kingdom.

Dr Johnson said: "What Matt and I have been working on would not normally have been predicted. This paper shows that animals can evolve more rapidly with germ plasm. Typically evolution is thought to be a gradual process, but this work suggests that the evolution of germ plasm can lead to explosive radiations of species. Importantly, because of the accelerated rate of evolution, genetic similarities between species can differ from that expected from their phylogenetic relationships. This has broad implications across biological disciplines."

Read more at Science Daily

How Flesh-Eating Strep Bacteria Evolved Into an Epidemic

Bacteria aren’t kind enough to leave behind a fossil record (save for cyanobacteria), but they’re evolving fast. Really fast. Their short life cycles mean that generations come rapid-fire, adapting through natural selection into the monster pathogens that are currently shrugging off our finest antibiotics.

It’s all the more troubling when we’re dealing with the flesh-eating variety. A new study, published today in the Proceedings of the National Academy of Sciences, details the evolution of one such bacteria, group A Streptococcus. By charting its evolution, scientists hope to gain invaluable insights into tackling subsequent generations of these menaces, and to begin to better understand the very nature of epidemics.

You’ve probably caught a strain of group A Streptococcus before, manifesting itself as strep throat. But depending on your immune system and the strain of Strep, you can be affected in many different ways, some of them fatal. “So you can get infections of muscles, you can get infections of cardiac valves, it can go to bone,” said physician Paul Sullam of the University of California, San Francisco Medical Center, who wasn’t involved in the study. “It can also get into your bloodstream. And when it does, it can produce this generalized disturbance of your cardiac function and lung function, something we call septic shock.” It can also lead to something called necrotizing fasciitis, the horrific destruction of soft tissue.

Strep wasn’t always so virulent and aggressive. Back in the early 1980s, it suddenly ramped up into into an epidemic, which continues to this day. And thanks to this new study, we now know exactly how that happened.

Scientists sequenced the genomes of thousands of strains of group A Strep in the biggest bacterial study of its kind to date. What they found was that, incredibly, only four tiny modifications to group A Strep caused it to explode into a worldwide epidemic.

“The first two events were the acquisition of two bacterial viruses,” said infectious disease pathologist James Musser of the Houston Methodist Research Institute, one of the authors of the paper. “Bacteria, just like humans, can get infected by viruses.”

Sometime in the 1980s, these viruses infected a single bacterial cell of group A Strep, transferring genes to the bacterium that allowed it to produce novel toxins. This is known as horizontal gene transfer, the acquisition of a trait not by mutations in reproduction, but from an outside source. Indeed, according to Sullam, “more common in this particular organism is it imports genetic material from other sources, predominantly by bacteriophages,” the viruses that infect them.

The third event was a regular old mutation in the genes of the bacteria, which produced an upgraded variant of one of the toxins. The fourth and final event that immediately preceded the epidemic was an attack from another virus, which had previously attacked another strain of group A Strep, picking up some of its genetic material. When it hit the epidemic strain, it transferred this material, which encoded two additional toxins and caused the strain to churn them out in massive quantities.

“This whole process ultimately resulted in two important character changes to the organism, which were the ability to cause an increased number of infections, and an increased severity of infection,” Musser said. Then you’re off and running with an epidemic.”

Read more at Wired Science

Sharks Contain More Pollutants Than Polar Bears

Greenland sharks joined the list of top Arctic predators that suffer under heavy loads of accumulated pollution in their bodies.

Biologists already knew that polar bears, orcas (killer whales) and people build up dangerous levels of toxins from feeding at the top of the Arctic food chain. Now, marine scientists have found evidence that a certain population of Greenland sharks (Somniosus microcephalus) could be one of the most contaminated Arctic predators.

Greenland sharks living near the Svalbard Islands, a Norwegian territory far to the north of Scandanavia, contained high levels the pesticides DDT and chlordane and the industrial chemical PCB, according to a study published last year in Science of the Total Environment.

These chemicals, collectively known as persistent organic pollutants (POPs), were banned or restricted in the United States and 90 other nations in a 2001 treaty. However, POPs don’t break down quickly in the environment. Instead, they build up over time in the food web, a process known as bioaccumulation.

POP particles stick to vegetation and microorganisms that animals eat, or are ingested directly. Then the chemicals stay in the food chain and build up as one creature devours another.

In the case of sharks near Svalbard, scientists suggested that the predators were more contaminated because they ate more seals than other Greenland shark populations. The seals contained higher levels of POPs than other prey, because the POPs in each fish the seals ate subsequently became trapped in the seals’ fat. When the sharks ate the seals, the POPs continued to build up.

Previous research on Greenland sharks from near Iceland and the Davis Strait in Canada found lower levels of POPs, likely because these sharks ate fewer seals.

Liver samples from the Svalbard seal-eating sharks revealed lower than normal levels of Vitamin A and higher levels of Vitamin E, which may have been a biological defense reaction to the POPs.

“We can conclude that the contaminants lead to reduced levels of vitamin A and increased levels of vitamin E in the sharks around Svalbard, but we don’t know if this affects their health or reproduction,” study co-author Bjørn Munro Jenssen of the Norwegian University of Science and Technology said in a press release. “We would have to study the species for many years.

“It seems that animals mobilize vitamin E stored in the liver and send it into the blood stream. Greenland sharks seem to be able to do this when needed. Lower levels of vitamin A in the body lead to a reduced immune defense and may affect reproduction negatively,” Jenssen said.

Jenssen noted that sharks in other areas may be even more contaminated.

“Seals living along the coast in Trøndelag in mid-Norway have pollutant levels five times higher than those in seals around Svalbard,” said Jenssen. “In the Oslo fjord the levels are ten times higher.”

Read more at Discovery News

Pluto May Have Deep Seas and Ancient Tectonic Faults

In July 2015 we get our first close look at the dwarf planet Pluto and its moon, Charon -- a fact that has scientists hypothesizing more than ever about what we might see there.

One of the latest ideas put forward is that perhaps the collision that likely formed Pluto and Charon heated the interior of Pluto enough to give it an internal liquid water ocean, which also gave the small world a short-lived plate tectonics system, like that of Earth.

“We predict that when New Horizons gets there it will see evidence of ancient tectonism,” said Brown University's Amy Barr, coauthor of a new paper with Geoffrey Collins in the latest issue of the journal Icarus. By 'ancient' Barr means sometime way back during the first billion years of the solar system's history.

Pluto Antifreeze?

Barr and Collins modeled the Pluto-Charon system based on the idea that the initial collision of the two bodies would have generated enough heat to melt the interior of Pluto creating ocean that would have survived for quite a while under an icy crust.

“Once you create an ocean on an icy body it's hard to get rid of it,” said Barr. That's because as the ocean freezes, the remaining liquid portion gets enriched with salts and ammonia -- which serve as antifreeze.

Next comes the part where that ocean could have created icy tectonic plates on Pluto's surface.

“One thing that we know is the angular momentum will be conserved as the system evolved,” said Barr. With that fact, they simulated a bunch of scenarios based on where Charon's orbit was right after the collision -- since nobody actually knows where Charon started. Then in each scenario they saw Charon's orbit gradually migrate outward -- just like the moon's orbit did around Earth.

When Pluto and Charon were closer and still hot from their collision they pulled more forcefully on each other and were more egg-shaped as a result. But as Charon moved away, Pluto became more spherical. But to change shape, the icy surface would have had to crack and create faults -- telltale signs of tectonics.

“In the scenarios we see, you generate more than enough stress to create all kinds of tectonic features,” Barr said.

Tectonic Features

But will New Horizons see those faults? Probably, says Jeffrey Moore, the head of New Horizon's geology and geophysics imaging team at the NASA Ames Research Center.

“It would probably be surprising if we didn't see tectonism,” said Moore.

One potential complication is Pluto weather. Telescopes discovered years ago that Pluto has an atmosphere when it is at its closest approach to the sun, and then that atmosphere freezes to the surface when Pluto is on the more distant part of its elliptical orbit. That regular change could be enough to erode the surface of Pluto to the point where it might hide the tectonic features.

“It's not inconceivable that the tectonics are eroded and covered up by sediments,” said Moore. But he doubts that will be the case, pointing to examples of worlds with atmospheres that freeze to the surface seasonally -- like Jupiter's moon Callisto.

Read more at Discovery News

Ancient Daddy Longlegs Had Extra Eyes

A 304-million-year-old fossil discovered in Eastern France shows primitive living harvestmen -- more commonly called daddy longlegs -- had one more pair of eyes than they do today.

The ancient harvestmen had a pair of eyes along the middle of the body -- like their modern counterparts -- but they also had a pair of eyes on the side of the body. The findings were reported by researchers from the American Museum of Natural History and the University of Manchester, in the journal Current Biology.

Scientists studied the fossil using high-resolution X-ray imaging at the Natural History Museum, London.

"Our X-ray techniques have allowed us to reveal this fossil in more detail than we would have dreamed possible two decades ago,” said Russell Garwood, a research fellow at the University of Manchester and a lead author on the study, in a release.

Though Harvestmen have eight legs and are categorized as arachnids, they're not spiders. They're more closely related to scorpions.

Read more at Discovery News