Amazing Science

FOXP2, a gene implicated in affecting speech and language, is held up as a textbook example of positive selection on a human-specific trait. But in a new paper, researchers challenge this finding. Their analysis of genetic data from a diverse sample of modern people and Neanderthals saw no evidence for recent, human-specific selection of FOXP2 and revises the history of how we think humans acquired language.

"A paper published in 2002 (Enard et al., Nature 418, 869-872) claimed there was a selective sweep relatively recently in human evolutionary history that could largely account for our linguistic abilities and even help explain how modern humans were able to flourish so rapidly in Africa within the last 50-100,000 years," says senior author Brenna Henn, a population geneticist at Stony Brook University and UC Davis. "I was immediately interested in dating the selective sweep and re-analyzing FOXP2 with larger and more diverse datasets, especially in more African populations."

Henn says that when the original 2002 work was done, the researchers did not have access to the modern sequencing technology that now provides data on whole genomes, so they only analyzed a small fraction of the FOXP2 gene in about 20 individuals, most of whom were of Eurasian descent. "We wanted to test whether their hypothesis stood up against a larger, more diverse dataset that more explicitly controlled for human demography," she says.

FOXP2 is highly expressed during brain development and regulates some muscle movements, aiding in language production. When the gene isn't expressed, it causes a condition called specific language impairment in which people may perform normally on cognitive tests but cannot produce spoken language. FOXP2 has also been shown to regulate language-like behaviors in mice and songbirds.

"In the past five years, several archaic hominid genomes have been sequenced, and FOXP2 was among the first genes examined because it was so important and supposedly human specific," says first author Elizabeth Atkinson of Stony Brook University and the Broad Institute of Harvard and MIT. "But this new data threw a wrench in the 2002 paper's timeline, and it turns out that the FOXP2 mutations we thought to be human specific, aren't."

There sure are a lot of people on planet Earth—a whopping 7 billion and counting. But how does this number, which of course represents the number of people now alive, compare to the number of people who have ever lived? Is it really true, as some folks maintain, that the number of people now alive is greater than the number of people who have lived and died since the dawn of Homo sapiens?

Not so, demographers say. “Back around 1980, and I think before then, there was this thing going around that 75 percent of people ever born were alive at the time,” Carl Haub, a demographer at the Population Reference Bureau, told The Huffington Post. “Occasionally I’ll still have someone call and they want to do a story on that particular number... It’s not true.”

Haub calculates that of all humans who have ever lived, only about 6.5 percent are now alive—which means that the number of people who have ever lived is larger than the world’s current population. Alas, the dead outnumber the living.

“You know, for much of early history there’s just slim evidence of how long people lived,” Haub said, “but it’s really how many were born is the important thing. There are really only two elements in it: what was the size of the population in 50,000 B.C. and in later periods, and how many births were there over the history from then to now?”

DNA of 500-year-old bacteria is first direct evidence of an epidemic — one of humanity's deadliest — that occurred after Spanish conquest.

One of the worst epidemics in human history, a sixteenth-century pestilence that devastated Mexico’s native population, may have been caused by a deadly form of salmonella from Europe, a pair of studies suggest.

In one study, researchers say they have recovered DNA of the stomach bacterium from burials in Mexico linked to a 1540s epidemic that killed up to 80% of the country's native inhabitants. The team reports its findings in a preprint posted on the bioRxiv server on 8 February1.

This is potentially the first genetic evidence of the pathogen that caused the massive decline in native populations after European colonization, says Hannes Schroeder, an ancient-DNA researcher at the Natural History Museum of Denmark in Copenhagen who was not involved in the work. “It’s a super-cool study.”

In 1519, when forces led by Spanish conquistador Hernando Cortés arrived in Mexico, the native population was estimated at about 25 million. A century later, after a Spanish victory and a series of epidemics, numbers had plunged to around 1 million.

The largest of these disease outbreaks were known as cocoliztli (from the word for ‘pestilence’ in Nahuatl, the Aztec language). Two major cocoliztli, beginning in 1545 and 1576, killed an estimated 7 million to 18 million people living in Mexico’s highland regions. “In the cities and large towns, big ditches were dug, and from morning to sunset the priests did nothing else but carry the dead bodies and throw them into the ditches,” noted a Franciscan historian who witnessed the 1576 outbreak.

There has been little consensus on the cause of cocoliztli — although measles, smallpox and typhus have all been mooted. In 2002, researchers at the National Autonomous University of Mexico (UNAM) in Mexico City proposed that a viral haemorrhagic fever, exacerbated by a catastrophic drought, was behind the carnage2. They compared the magnitude of the 1545 outbreak to that of the Black Death in fourteenth-century Europe. 

When Dutch archaeologist D. A. Hooijer first saw a pair of weathered teeth recovered from a remote cave on the Indonesian island of Sumatra, he noted that they were about the right size and shape to belong to modern humans. But in 1948, he couldn’t be sure of their identity or their age. Now, harnessing cutting-edge science, a group of researchers has confirmed what Hooijer had suspected: Modern humans lived in Southeast Asia as far back as 73,000 years ago—about 20,000 years earlier than previously thought. The earlier timeline helps fill in the blanks on the migration routes of our early ancestors and bolsters an emerging theory that humans may have dwelled in rain forests much sooner than researchers had assumed.

Previous studies suggested that after evolving in Africa, modern humans eventually made their way to Southeast Asia, but researchers have argued whether they arrived about 50,000 years ago or earlier. Recent studies put modern humans in Australia by about 65,000 years ago, but there has been little direct evidence of an early presence in Southeast Asia.

To unravel the mystery, researchers led by geochronologist Kira Westaway of Macquarie University in Sydney, Australia, decided in 2008 to give the Sumatran teeth another look. She and her team used new techniques, including micro–computed tomography scanning to precisely measure the thickness of the enamel, and luminescence dating to determine when minerals in the rock surrounding the teeth were last exposed to sunlight. They found thick enamel, confirming that the teeth are from modern humans, and pegged the date to between 63,000 and 73,000 years ago, they report today in Nature.

Remains from Morocco dated to 315,000 years ago push back our species' origins by 100,000 years — and suggest we didn't evolve only in East Africa.

At an archaeological site near the Atlantic coast, finds of skull, face and jaw bones identified as being from early members of our species have been dated to about 315,000 years ago. That indicates H. sapiens appeared more than 100,000 years earlier than thought: most researchers have placed the origins of our species in East Africa about 200,000 years ago. The finds, which are published on 7 June in Nature1, 2, do not mean that H. sapiens originated in North Africa. Instead, they suggest that the species' earliest members evolved all across the continent, scientists say.

“Until now, the common wisdom was that our species emerged probably rather quickly somewhere in a ‘Garden of Eden’ that was located most likely in sub-Saharan Africa,” says Jean-Jacques Hublin, an author of the study and a director at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Now, “I would say the Garden of Eden in Africa is probably Africa — and it’s a big, big garden.” Hublin was one of the leaders of the decade-long excavation at the Moroccan site, called Jebel Irhoud.

Hublin first became familiar with Jebel Irhoud in the early 1980s, when he was shown a puzzling specimen of a lower jawbone of a child from the site. Miners had discovered a nearly complete human skull there in 1961; later excavations had also found a braincase, as well as sophisticated stone tools and other signs of human presence.

The bones “looked far too primitive to be anything understandable, so people came up with some weird ideas”, Hublin says. Researchers guessed they were 40,000 years old and proposed that Neanderthals had lived in North Africa.

More recently, researchers have suggested that the Jebel Irhoud humans were an ‘archaic’ species that survived in North Africa until H. sapiens from south of the Sahara replaced them. East Africa is where most scientists place our species’ origins: two of the oldest known H. sapiens fossils — 196,000 and 160,000-year-old skulls3, 4 — come from Ethiopia, and DNA studies of present-day populations around the globe point to an African origin some 200,000 years ago5.

Our close cousins definitely ate each other, but no one knows why.

Neandertals ate each other—at least once in a while—according to a new analysis of bones unearthed in a Belgian cave. The remains were excavated near Goyet beginning in the 19th century and now sit in museums in Brussels. The outdated excavation techniques make it impossible to reconstruct how these Neandertals lived, but when researchers examined the bones, it was unmistakably clear what happened to them after they died. Many of the bones were covered in cut marks and dents caused by pounding, indicating that the meat and marrow had been removed. The researchers also spotted what appear to be bite marks running up and down finger bones. The marks were identical to those found on reindeer and horse bones also uncovered at the site, suggesting all three species were prepared and eaten, the researchers report this week in Scientific Reports.

A few of the Neandertal bones also showed additional wear and tear, suggesting they were later used to shape stone tools. The bones are between 40,500 and 45,500 years old, which is before Homo sapiens arrived in the region, so the only possible culprits are the Neandertals themselves. Although scientists knew that Neandertals had practiced cannibalism in Croatia, this is the first evidence of it in northern Europe. No one yet knows if Neandertal cannibalism was a ritual practice, reserved for special occasions and imbued with special meaning, or if they were just really, really hungry.

Deep in the caves of Goyet in Belgium researchers have found the grisly evidence that the Neanderthals did not just feast on horses or reindeer, but also on each other.

Human bones from a newborn, a child and four adults or teenagers who lived around 40,000 years ago show clear signs of cutting and of fractures to extract the marrow within, they say. "It is irrefutable, cannibalism was practised here," says Belgian archaeologist Christian Casseyas as he looks inside a cave halfway up a valley in this site in the Ardennes forest.

The bones in Goyet date from when Neanderthals were nearing the end of their time on earth before being replaced by Homo sapiens, with whom they also interbred.

Once regarded as primitive cavemen driven to extinction by smarter modern humans, studies have found that Neanderthals were actually sophisticated beings who took care of the bodies of the deceased and held burial rituals.

But there is a growing body of proof that they also ate their dead.

“The most terrible of all the ministers of death” may have started afflicting humans in the 1500s, altering our understanding of the disease.

A scientific consortium led by Dr. Eleanor Scerri, British Academy Postdoctoral Fellow at the University of Oxford and researcher at the Max Planck Institute for the Science of Human History, has found that human ancestors were scattered across Africa, and largely kept apart by a combination of diverse habitats and shifting environmental boundaries, such as forests and deserts. Millennia of separation gave rise to a staggering diversity of human forms, whose mixing ultimately shaped our species.

While it is widely accepted that our species originated in Africa, less attention has been paid to how we evolved within the continent. Many had assumed that early human ancestors originated as a single, relatively large ancestral population, and exchanged genes and technologies like stone tools in a more or less random fashion.

In a recent paper published in Trends in Ecology and Evolution, this view is challenged, not only by the usual study of bones (anthropology), stones (archaeology) and genes (population genomics), but also by new and more detailed reconstructions of Africa's climates and habitats over the last 300,000 years.

One species, many origins

"Stone tools and other artifacts -- usually referred to as material culture -- have remarkably clustered distributions in space and through time," said Dr. Eleanor Scerri, researcher at the Max Planck Institute for the Science of Human History and the University of Oxford, and lead author of the study. "While there is a continental-wide trend towards more sophisticated material culture, this 'modernization' clearly doesn't originate in one region or occur at one time period."

Human fossils tell a similar story. "When we look at the morphology of human bones over the last 300,000 years, we see a complex mix of archaic and modern features in different places and at different times," said Prof. Chris Stringer, researcher at the London Natural History Museum and co-author on the study. "As with the material culture, we do see a continental-wide trend towards the modern human form, but different modern features appear in different places at different times, and some archaic features are present until remarkably recently."

Rearing on its hind legs, the giant ground sloth would have been a formidable prey for anyone, let alone humans without modern weapons.

Predator-prey interactions revealed by vertebrate trace fossils are extremely rare. A group of paleontologists and associated scientists now present footprint evidence from the White Sands National Monument in New Mexico for the association of sloth and human trackways. Geologically, the sloth and human trackways were made contemporaneously, and the sloth trackways show evidence of evasion and defensive behavior when associated with human tracks. Behavioral inferences from these trackways indicate prey selection and suggest that humans were harassing, stalking, and/or hunting the now-extinct giant ground sloth in the terminal Pleistocene.

Homo sapiens, Neanderthals and other recent human relatives may have begun hunting large mammal species down to size — by way of extinction — at least 90,000 years earlier than previously thought, says a new study published in the journal Science.

Elephant-dwarfing wooly mammoths, elephant-sized ground sloths and various saber-toothed cats highlighted the array of massive mammals roaming Earth between 2.6 million and 12,000 years ago. Prior research suggested that such large mammals began disappearing faster than their smaller counterparts — a phenomenon known as size-biased extinction — in Australia around 35,000 years ago.

With the help of emerging data from older fossil and geologic records, the new study estimated that this size-biased extinction started at least 125,000 years ago in Africa. By that point, the average African mammal was already 50 percent smaller than those on other continents, the study reported, despite the fact that larger landmasses can typically support larger mammals. But as humans migrated out of Africa, other size-biased extinctions began occurring in regions and on timelines that coincide with known human migration patterns, the researchers found. Over time, the average body size of mammals on those other continents approached and then fell well below Africa’s. Mammals that survived during the span were generally far smaller than those that went extinct.

The magnitude and scale of the recent size-biased extinction surpassed any other recorded during the last 66 million years, according to the study, which was led by the University of New Mexico’s Felisa Smith. “It wasn’t until human impacts started becoming a factor that large body sizes made mammals more vulnerable to extinction,” said the University of Nebraska-Lincoln’s Kate Lyons, who authored the study with Smith and colleagues from Stanford University and the University of California, San Diego. “The anthropological record indicates that Homo sapiens are identified as a species around 200,000 years ago, so this occurred not very long after the birth of us as a species. It just seems to be something that we do.

“From a life-history standpoint, it makes some sense. If you kill a rabbit, you’re going to feed your family for a night. If you can kill a large mammal, you’re going to feed your village.” By contrast, the research team found little support for the idea that climate change drove size-biased extinctions during the last 66 million years. Large and small mammals seemed equally vulnerable to temperature shifts throughout that span, the authors reported.

Nearly 500 years ago, in what we know call Mexico, a disease started rippling through the population.

It bore the name cocoliztli, meaning ‘pestilence,’ and it killed between five and 15 million people in just three years. As many plagues were at the time, it proved deadly and mysterious, burning through entire populations. Occurring centuries before John Snow’s work on cholera gave rise to epidemiology, data on the disease’s devastation was sparse. Over the years, researchers and historians attempted to pin the blame for the illness on measles, plague, viral hemorrhagic fevers like Ebola, and typhoid fever—a disease caused by a variation of the bacteria Salmonella enterica.

In a paper published this week in Nature Ecology & Evolution, researchers present evidence that the latter was the most likely candidate in this cast of microbial miscreants. The study was pre-printed in biorxiv last year. The researchers detected the genome of a different variety of Salmonella enterica (the specific variety is Paratyphi C) in teeth of individuals buried in a cemetery historically linked to the deadly outbreak.

The researchers used a technique called MALT (MEGAN Alignment Tool) to analyze DNA left behind in the pulp of the teeth. MALT takes a sample of material, in this case from a tooth, and compares it to 6,247 known bacterial genomes. The results identified Salmonella enterica in 10 burials associated with the epidemic.

Indigenous people have been on the far northeastern edge of Canada for most of the last 10,000 years, moving in shortly after the ice retreated from the Last Glacial Maximum. Archaeological evidence suggests that people with distinct cultural traditions inhabited the region at least three different times with a possible hiatus for a period between 2,000 and 3,000 years ago.

Now, researchers who've examined genetic evidence from mitochondrial DNA provide evidence that two of those groups, known as the Maritime Archaic and Beothuk, brought different matrilines to the island, adding further support to the notion that those groups had distinct population histories. The findings are published in Current Biology on October 12.

"Our paper suggests, based purely on mitochondrial DNA, that the Maritime Archaic were not the direct ancestors of the Beothuk and that the two groups did not share a very recent common ancestor," says Ana Duggan of McMaster University. "This in turn implies that the island of Newfoundland was populated multiple times by distinct groups."

The relationship between the older Maritime Archaic population and Beothuk hadn't been clear from the archaeological record. With permission from the current-day indigenous community, Duggan and her colleagues, led by Hendrik Poinar, examined the mitochondrial genome diversity of 74 ancient remains from the island together with the archaeological record and dietary isotope profiles. All samples were collected from tiny amounts of bone or teeth.

Scientists discover the oldest homo sapiens fossils at Jebel Irhoud, Morocco

An international research team led by Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology (Leipzig, Germany) and Abdelouahed Ben-Ncer of the National Institute for Archaeology and Heritage (INSAP, Rabat, Morocco) uncovered fossil bones of Homo sapiens along with stone tools and animal bones at Jebel Irhoud, Morocco. The finds are dated to about 300 thousand years ago and represent the oldest securely dated fossil evidence of our own species. This date is 100 thousand years earlier than the previous oldest Homo sapiens fossils. The discoveries reported in two papers in the June 8th issue of the journal Nature by Hublin et al. and by Richter et al. reveal a complex evolutionary history of mankind that likely involved the entire African continent.

Both genetic data of present day humans and fossil remains point to an African origin of our own species, Homo sapiens. Previously, the oldest securely datedHomo sapiens fossils were known from the site of Omo Kibish in Ethiopia, dated to 195 thousand years ago. At Herto, also in Ethiopia, a Homo sapiens fossil is dated to 160 thousand years ago. Until now, most researchers believed that all humans living today descended from a population that lived in East Africa around 200 thousand years ago. "We used to think that there was a cradle of mankind 200 thousand years ago in east Africa, but our new data reveal that Homo sapiensspread across the entire African continent around 300 thousand years ago. Long before the out-of-Africa dispersal of Homo sapiens, there was dispersal within Africa," says palaeoanthropologist Jean-Jacques Hublin.

Study suggests disease was more prevalent than previously believed.

 Some 2,250 years ago in Egypt, a man known today only as M1 struggled with a long, painful, progressive illness. A dull pain throbbed in his lower back, then spread to other parts of his body, making most movements a misery. When M1 finally succumbed to the mysterious ailment between the ages of 51 and 60, his family paid for him to be mummified so that he could be reborn and relish the pleasures of the afterworld.

A few years ago, an international research team has diagnozed what ailed M1: The oldest known case of prostate cancer in ancient Egypt and the second oldest case in the world. The earliest diagnosis of prostate cancer came from the 2700-year-old skeleton of a Scythian king in Russia. Moreover, this study published in the International Journal of Paleopathology, suggests that earlier investigators may have underestimated the prevalence of cancer in ancient populations because high-resolution computerized tomography (CT) scanners capable of finding tumors measuring just 1 to 2 millimeters in diameter only became available in 2005. "I think earlier researchers probably missed a lot without this technology," says team leader Carlos Prates, a radiologist in private practice at Imagens Médicas Integradas in Lisbon.

Prostate cancer begins in the walnut-sized prostate gland, an integral part of the male reproductive system. The gland produces a milky fluid that is part of semen and it sits underneath a man's bladder. In aggressive cases of the disease, prostate cancer cells can metastasize, or spread, entering the bloodstream and invading the bones. After performing high-resolution scans on three Egyptian mummies in the collection of the National Archaeological Museum in Lisbon, Prates and colleagues detected many small, round, dense tumors in M1's pelvis and lumbar spine, as well as in his upper arm and leg bones. These are the areas most commonly affected by metastatic prostate cancer. "We could not find any evidence to challenge this diagnosis," Prates says.

More than 100,000 years ago in a Siberian cave there lived a child with a loose tooth. One day her molar fell out, and fossilized over many millenniums, keeping it safe from the elements and the tooth fairy.

But she wasn’t just any child. Scientists say she belonged to a species of extinct cousins of Neanderthals and modern humans known today as the Denisovans. And in a paper published Friday in the journal Science Advances, a team of paleoanthropologists reported that she is only the fourth individual of this species ever discovered.

“We only have relatively little data from this archaic group, so having any additional individuals is something we’re very excited about,” saidViviane Slon, a doctoral candidate at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and lead author of the study.

The scant fossil record for these ancient hominins previously included only two adult molars and a finger bone. The Denisovans were only correctly identified in 2010 by a team of researchers led by Svante Paabo, who used the finger bone to sequence the species’ genome.

Full Paper is here (free)

Farming was first introduced to southeastern Europe in the mid-7th millennium BCE - brought by migrants from Anatolia who settled in the region before spreading throughout Europe. However, the dynamics of the interaction between the first farmers and the indigenous hunter-gatherers remain poorly understood because of the near absence of ancient DNA from the region. We report new genome-wide ancient DNA data from 204 individuals-65 Paleolithic and Mesolithic, 93 Neolithic, and 46 Copper, Bronze and Iron Age-who lived in southeastern Europe and surrounding regions between about 12,000 and 500 BCE.

A large group of researchers now document that the hunter-gatherer populations of southeastern Europe, the Baltic, and the North Pontic Steppe were distinctive from those of western Europe, with a West-East cline of ancestry. They show that the people who brought farming to Europe were not part of a single population, as early farmers from southern Greece are not descended from the Neolithic population of northwestern Anatolia that was ancestral to all other European farmers. The ancestors of the first farmers of northern and western Europe passed through southeastern Europe with limited admixture with local hunter-gatherers, but they show that some groups that remained in the region mixed extensively with local hunter-gatherers, with relatively sex-balanced admixture compared to the male-biased hunter-gatherer admixture that prevailed later in the North and West. After the spread of farming, southeastern Europe continued to be a nexus between East and West, with intermittent steppe ancestry, including in individuals from the Varna I cemetery and associated with the Cucuteni-Trypillian archaeological complex, up to 2,000 years before the Steppe migration that replaced much of northern Europe's population.

From Amazonia to Siberia, some human populations the world over communicate by whistling. More complex than it sounds, whistled speech intrigues linguists and neuroscientists alike. Linguist and bio-acoustician Julien Meyer tells us about this astonishing method of communication.

New evidence involving the ancient poop of some of the huge and astonishing creatures that once roamed Australia indicates the primary cause of their extinction around 45,000 years ago was likely a result of humans, not climate change.

New research led by the University of Southampton shows Neanderthals kept coming back to a coastal cave site in Jersey from at least 180,000 years ago until around 40,000 years ago.

As part of a re-examination of La Cotte de St Brelade and its surrounding landscape, archaeologists from Southampton, together with experts from two other universities and the British Museum, have taken a fresh look at artefacts and mammoth bones originally excavated from within the site’s granite cliffs in the 1970s. Their findings are published in the journal Antiquity.

The researchers matched types of stone raw material used to make tools to detailed mapping of the geology of the sea bed, and studied in detail how they were made, carried and modified. This helped reconstruct a picture of what resources were available to Neanderthals over tens of thousands of years – and where they were travelling from.

Lead author Dr Andy Shaw of the Centre for the Archaeology of Human Origins (CAHO) at the University of Southampton said: “La Cotte seems to have been a special place for Neanderthals. They kept making deliberate journeys to reach the site over many, many generations. We can use the stone tools they left behind to map how they were moving through landscapes, which are now beneath the English Channel. 180,000 years ago, as ice caps expanded and temperatures plummeted, they would have been exploiting a huge offshore area, inaccessible to us today.”