Dear male reader: Just so you know, your sperm isn’t that different from a sea anemone’s.

Sperm is so vital, a new study in PLoS Genetics found, that one of the genes responsible for it hasn’t changed in 600 million years. Insects, humans, marine invertebrates, other mammals, even fish—the males of all these creatures share a common sperm gene that dates back to before all those animals diverged all those millions of years ago, according to the team led by Eugene Xu.

From an evolutionary point of view, that longevity is simply stunning.

“It’s really surprising because sperm production gets pounded by natural selection,” Xu said. “It tends to change due to strong selective pressures for sperm-specific genes to evolve. There is extra pressure to be a super male to improve reproductive success. This is the one sex-specific element that didn’t change across species. This must be so important that it can’t change” [MSNBC].

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Perhaps you’re one of those people who get their dander up when you hear creationists saying “I’m not descended from some monkey” not only for the obvious reason, but also because you can’t help but blurt out, “No, you mean ‘ape!’ We’re apes, not monkeys.”

Indeed, our superfamily, Hominoidea, split from the group labeled “old world monkeys” millions of years ago—but perhaps not as many million as we thought. In Nature this week, a team of scientists report on a 28-29 million year old fossil that appears to predate the split, meaning the separation would have happened more recently than other studies suggested.

The partial skull of this new creature, which the team dubbed Saadanius hijazensis, turned up in Saudi Arabia in February 2009.

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It’s what happens to your brain after you’re born that makes you human.

Jason Hill and colleagues were comparing the structure of newborn brains to those of adults when they came upon a striking find, documented this week in the Proceedings of the National Academy of Sciences. Clearly, the brain expands greatly as you grow from baby to adult. But the researchers discovered not only that the brain grows in a non-uniform way, but also that the parts of the brain that change most rapidly as people grow up are the same parts that changed the most as humans evolved away from our primate relatives.

The research revealed that brain regions involved in higher cognitive and executive processes—such as language and reasoning—grow about twice as much as regions associated with basic senses such vision and hearing…. “The parts of the [brain] that have grown the most to make us uniquely humans are the same regions that tend to grow the most postnatally,” Hill said [National Geographic].

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It makes sense: stay where it’s warm, sunny, and there’s a lot of food. What, then, were prehistoric people doing on the British seashore? New research published today in Nature pushes human arrival in Britain back to about 800,000 years ago, roughly 100,000 years earlier than our previous estimations. The evidence? A trove of 70 flint tools found on the Happisburgh shore in Norfolk.

Dating artifacts that old isn’t easy (for example, carbon dating doesn’t work), so the researchers had to be thorough. Led by Simon A. Parfitt of The Natural History Museum in London and Nick Ashton of the British Museum, London as part of the Ancient Human Occupation of Britain project, the team used both biological and physical evidence to date the tools. Looking at insect and plant fossils found with the artifacts, researchers determined that the species dated back to the Early Pleistocence period, between 990,000 and 780,000 years ago. The researchers also tested sediment around the tools, and established that they were buried when the Earth’s magnetic field was flipped. The last time this happened was also about 780,000 years ago.

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Clearly, the people of Tibet must have evolved quickly to tolerate a life spent living at the top of the world. How quickly? A study out in this week’s Science, which compared Tibetans to Han Chinese to see the differences in their DNA, says that the two groups may have diverged no more than 3,000 years ago. If natural selection has changed Tibetans in such a short time, it would be the fastest known example of human evolution. But not everybody is buying this time line.

As DISCOVER noted when a similar study by another team came out in May, natives of the Tibetan plateau seem to survive the altitude because their bodies make less hemoglobin. It’s somewhat counter-intuitive:

In theory higher levels of haemoglobin would be beneficial, because this would improve oxygen transport. But high levels could make the blood thicker and less efficient at carrying oxygen, says Jay Storz of the University of Nebraska-Lincoln [New Scientist]. (Storz writes the accompanying commentary in Science.)

Looking at the differences in genes that regulate that, the team found vast differences between the Han and the Tibetans, with one version appearing in 87 percent of Tibetans studied but only 9 percent of Chinese. However, the assertion by the scientists at the Beijing Genome Institute—that their findings mean the two group broke apart just three millennia ago—has ruffled archaeologists who believe that the Tibetan plateau has been continuously occupied for much, much longer: more like 7,000 to 21,000 years.

For more about all of this, check out Razib Khan’s post at Gene Expression.

Related Content:
Gene Expression: Very Recent Altitude Adaptation in Tibet
Gene Expression: Tibet & Tibetans, Not Coterminus
80beats: Found: The Genes That Help Tibetans Live at the Top of the World
DISCOVER: High-Altitude Determines Who Survives in Tibet

Image: Wikimedia Commons

What struck down ancient Egypt’s King Tutankhamen at the tender age of 19?

Just this winter, Egyptian researchers seemed to think they had a definitive answer. After years of genetic tests and CT scans, they concluded that royal incest had produced a sickly boy with a bone disorder, and argued that a malaria-bearing parasite finished him off. But now a team of German researchers is arguing that the observations actually point to death from the inherited blood disorder sickle cell disease (SCD).

People with SCD carry a mutation in the gene for haemoglobin which causes their red blood cells to become rigid and sickle-shaped. A single copy of the sickle-cell gene confers increased immunity to malaria, so it tends to be common in areas where the infection is endemic – such as ancient Egypt. People with two copies of the gene suffer severe anaemia and often die young. [New Scientist]

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No offense, Lucy, but at three feet, six inches you were kind of short. Your diminutive, 3.2 million-year-old bones made it difficult to tell whether your species could even walk like us. Fortunately, researchers in Ethiopia have uncovered an older, bigger relative. As described in Proceedings of the National Academy of Sciences, some researchers believe that these new bones show that members of Lucy’s species, Australopithecus afarensis, could walk like modern humans. 

The paper’s authors call him Kadanuumuu (kah-dah-nuu-muu)–”big man” in the Afar language. Big Man still isn’t really that big by today’s standard: His 3.6 million-year-old bones show that he stood at around five feet.

The fossilized remains don’t include a head, but Big Man has many of the same bones as Lucy, and also others previously missing: a shoulder blade and a rib cage bits. Lead researcher Yohannes Haile-Selassie argues that Big Man’s skeleton upends previous beliefs about Lucy’s love of tree climbing and more primitive walk.

“This individual was fully bipedal and had the ability to walk almost like modern humans,” said Haile-Selassie. “As a result of this discovery, we can now confidently say that ‘Lucy’ and her relatives were almost as proficient walking on two legs as we are, and that the elongation of our legs came earlier in our evolution that previously thought.” [Cleveland Museum of Natural History]

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Three jaw-less heads and one really old shoe. These aren’t the clues in a Law and Order episode; they’re findings from a limestone cave in Armenia. As described in a paper published yesterday in PLoS ONE, archaeologists believe they have found the world’s oldest leather shoe: it’s 5,500 years old.

“It’s pretty weird,” said lead author Ron Pinhasi to CNN regarding the disembodied heads and the placement of the well-preserved shoe. The ancient sneaker was stuffed with grass, though archaeologists can’t say whether the grass was intended as insulation or whether it helped maintain the shoe’s shape.

“We thought originally it could be a discard, but at the same time, it’s very strange, because we have only one shoe, and it’s in very good shape,” Pinhasi said. “It looks like it was more than likely deliberately placed in this way.” [CNN]

The right-footed shoe–which looks a bit like a baked potato–has some features that might entice even modern buyers: for one, its maker fashioned it from a single piece of cow leather (like a pricey pair of today’s “whole cut” footwear), and it has leather laces. It’s about a women’s size seven, but, researchers say, it might have graced a small-footed man.

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It took Turkish bees to make Israel flow with milk and honey.

When archaeologist Amihai Mazar and colleagues turned up 3,000-year-old remains of hundreds of preserved beehives from the ancient town of Tel Rehov in 2007, it was the first confirmation of the ancient beekeeping suggested by Egyptian paintings and Biblical references. Now, three years later, the team has published a paper in the Proceedings of the National Academy of Sciences with the analysis of the “honeybee workers, drones, pupae, and larvae” found inside those hives. Surprise—they’re from Turkey, hundreds of miles away.

The findings “would imply an incredible amount of commodity trading of bees,” said bee expert Gene Kritsky of the College of Mount St. Joseph in Cincinnati, editor of American Entomologist. The importation of Italian bees to the United States in the 1860s “was thought to be a big deal then,” he said, “but the Israelis may have been doing this as far back as the first millennium BC” [Los Angeles Times].

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Just how connected are the Jews, genetically speaking? Despite the fact that pockets of Jewish people are spread around the globe, the new genetic analysis by Harry Ostrer and his team says that they share genetic markers that go back thousands of years.

In the study in the American Journal of Human Genetics, Ostrer investigated Jewish people from all over the world:

Historians divide the world’s 13 million living Jews into three groups: Middle Eastern, or Oriental, Jews; Sephardic Jews from Spain and Portugal; and Ashkenazi Jews from Europe [ScienceNOW].

Taking nuclear DNA samples from 237 Jews—some from each group—the team compared them to samples from more than 400 non-Jewish people who lived in the same regions.

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Your brain is hungry. That big gray calculating machine in your head is an energy hog that needs lots of calories—more than the diet of fruits and plants that our distant hominin ancestors probably ate could provide. It’s a mystery, then, just how human ancestors like Homo erectus—who were around when our craniums started to expand in a hurry—ate enough to start growing big brains. But buried in Kenya, a two-million-year-old hint has emerged: Those hominins started eating seafood way back then, archaeologists say.

Near a place called Lake Turkana, archaeologists David Braun found two intriguing groups of items: The bones of fish, turtles, and even crocodiles with the scars of stone tools still showing, and stone fragments that Braun says come from the simple tools these hominins used to carve up the marine animals. He and his colleagues report the find of our ancestors’ ancient feast in the Proceedings of the National Academy of Sciences.

Today, their leftovers—in the form of hundreds of bones and several thousand stone tools—are the earliest “definitive evidence” of hominins butchering and eating aquatic animals, which are rich in fatty acids essential for growing bigger brains [ScienceNOW].

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It’s a good thing that the early English settlers of America were hardy and stubborn, because they certainly didn’t have good timing. The settlers who established the Jamestown colony in Virginia is 1607 arrived during a historic drought, according to the records kept in tree rings, the worst in the area in 800 years. And now researchers have created an even more detailed picture of the dire climate situation those colonists stumbled into, and they did it with the colonists’ trash.

Oyster shells, to be exact.

The telltale oysters were unearthed from a well that sat within the fort at Jamestown, about 100 yards from the [James] river. Among other material dumped into the well, the shells came from three distinct layers up to 3.5 meters deep. The well’s water level originally sat deeper, at a depth of about 4 meters, so Spero and his colleagues suggest that the settlers abandoned the well — which either ran dry during the drought or was infiltrated by salty groundwater — and converted it into a trash pit [Science News].

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The bones of our ancestors do not speak across time with ultimate clarity. The fossils with which scientists reconstruct our family tree are often fragments that offer hints and clues to where we came from. So it comes as no surprise when, as part of the flow of science, researchers offer counter-interpretations to even the most famous of finds.

That’s what happening to Ardi.

Last October Ardipithecus ramidus hit the main stage when, after 17 years of study, a large team led by paleoanthropologist Tim White published its work in the journal Science. The 4.4-million-year-old find shakes up our understanding of our own history, White said—primarily the story of how and when we learned to walk.

Ardi cast doubt on the widely accepted view that our ancestors became bipeds because they left the forest and entered a flatland savanna habitat that demanded it. But Ardi appeared to be a kind of hybrid, comfortable in the trees and on the ground. And, White said, analysis of the site where the fossil was found indicated that Ardi lived in a woodland habitat. If it’s true that early humans walked in the woods, then the “savanna hypothesis” would be swept away.

But not so fast. In today’s edition of Science, two teams of scientists respond (1, 2) with doubts about the story of Ardi.

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Sometimes you have to change your vantage point to really see something.

The New York Times today reports on the work of Diane and Arlen Chase, who spent more than 20 years cutting through the Central American jungle to survey the Ancient Mayan city of Caracol in present-day Belize. But when they were turned on to the possibility of using flyover missions equipped with laser technology that could see to the jungle floor, their research accelerated dramatically.

In only four days, a twin-engine aircraft equipped with an advanced version of lidar (light detection and ranging) flew back and forth over the jungle and collected data surpassing the results of two and a half decades of on-the-ground mapping, the archaeologists said. After three weeks of laboratory processing, the almost 10 hours of laser measurements showed topographic detail over an area of 80 square miles, notably settlement patterns of grand architecture and modest house mounds, roadways and agricultural terraces [The New York Times].

Given such dramatic results, you might think the scientists would have started working from above earlier. After all, learning by bouncing lasers around isn’t new: Satellites have measured the Antarctic ice by reflecting lasers of the sheet and back into space, then measuring how long it took. Scientists have bounced lasers off reflectors that U.S. and Russian moon missions left behind, measuring the moon’s slow progression away from the Earth.

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Ever since anthropologists figured out that early humans and Neanderthals coexisted for a span of prehistory, they’ve wondered–did the two species, you know, make friends? Now a fascinating new genetics study reveals that Homo sapiens and Neanderthals did indeed interbreed, and the evidence is still to be found in the human genome.

Researchers from Germany’s Max Planck Institute for Evolutionary Anthropology first sequenced the entire Neanderthal genome from powdered bone fragments found in Europe and dating from 40,000 years ago–a marvelous accomplishment in itself. Then, they compared the Neanderthal genome to that of five modern humans, including Africans, Europeans, and Asians. The researchers found that between 1 percent and 4 percent of the DNA in modern Europeans and Asians was inherited from Neanderthals, which suggests that the interbreeding took place after the first groups of humans left Africa.

Anthropologists have long speculated that early humans may have mated with Neanderthals, but the latest study provides the strongest evidence so far, suggesting that such encounters took place around 60,000 years ago in the Fertile Crescent region of the Middle East [The Guardian].

The study, published in Science and made available to the public for free, opens up new areas for research. Geneticists will now probe the function of the Neanderthal genes that humans have hung on to, and can also look for human genes that may have given us a competitive edge over Neanderthals.

Erik Trinkaus, an anthropologist at Washington University in St. Louis, who has long argued that Neanderthals contributed to the human genome, welcomed the study, commenting that now researchers “can get on to other things than who was having sex with who in the Pleistocene” [AP].

For a much deeper dive into these issues, head to Carl Zimmer’s post at The Loom and Razib Khan’s post at Gene Expression.

Related Content:
The Loom: Skull Caps and Genomes
Gene Expression: Breaking: There’s a Little Bit of Neandertal in All of Us
80beats: We May Soon Be Able to Clone Neanderthals. But Should We?
80beats: Crafty & Clever Neanderthals Made Jewelry 50,000 Years Ago
80beats: Did Spear-Throwing Humans Kill Neanderthals?
80beats: Rough Draft of the Neanderthal Genome is Complete!
DISCOVER: Works in Progress asks whether we rubbed out Neanderthals, or rubbed off on them

Image: Max Planck Institute EVA. The researchers hang out with their Neanderthal relation.