"Kotias remains," Eppie Jones
"Kotias remains," Eppie Jones

DNA From a Fourth Tribe of European Ancestors Has Been Found

"Kotias remains," Eppie Jones
"Kotias remains," Eppie Jones

Prior to summer 2015, researchers believed that all Europeans had a shared ancestry stemming from three tribal populations: European hunter-gatherers, early European farmers, and ancient North Eurasians. According to an article published this week in the journal Nature Communications, by studying the genomes of ancient skeletons found in two caves in Western Georgia (Kotias Klde and Satsurblia), geneticists have discovered a fourth group, Caucasus hunter-gatherers, who also contributed DNA to the continent.

Satsurblia cave, where another sample was found. Image credit: Eppie Jones

The Caucasus hunter-gatherers are believed to have mixed with another group of hunter-gatherers around 25,000 years ago, "laying the genetic foundations of the Yamnaya people," according to the BBC. Yamnaya herders from the region, which includes present-day Russia and the Ukraine, entered Europe around 5000 years ago, possibly because of the spread of disease back home.

"The question of where the Yamnaya come from has been something of a mystery up to now," Andrea Manica, of the University of Cambridge, told the BBC. "We can now answer that as we've found that their genetic make-up is a mix of Eastern European hunter-gatherers and a population from this pocket of Caucasus hunter-gatherers who weathered much of the last Ice Age in apparent isolation." The group may have been responsible for introducing Indo-Aryan languages to the region, and are also believed to have influenced the cultures of central and south Asia.

To read more about the analysis of the skeleton genomes and of the Caucasus, head over to Nature Communications.

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Drought Reveals Ancient Sites in Scotland That Can Only Be Spotted From the Air
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iStock

Typically rainy Scotland is in the middle of an unusually dry summer—and local archaeologists are taking advantage of it. As the BBC reports, the drought has revealed ancient sites, including Roman camps and Iron Age graves, that have been hidden by farm soil for years.

Historic Environment Scotland has been conducting aerial surveys of the country's landscape since the 1930s, but it's in seasons like this, when the crops recede during dry weather, that the buried remains of ancient structures are easiest to spot. Conditions this summer have been the best since 1976 for documenting archaeological sites from the sky.

Aerial view of field.
Historic Environment Scotland

The crescent-shaped crop mark in the photo above indicates a souterrain, or underground passageway, that was built in the Scottish Borders during the Iron Age. The surveyors also found remains of a Roman temporary camp, marked by straight lines in the landscape, built in modern-day Lyne—an area south of Edinburgh already known to have housed a complex of Roman camps and forts.

Aerial view of field.
Historic Environment Scotland

In the image below you'll see four small ditches—three circles and one square—that were likely used as burial sites during the Iron Age. When crops are planted over an ancient ditch, they have more water and nutrients to feed on, which helps them grow taller and greener. Such crops are especially visible during a drought when the surrounding vegetation is sparse and brown.

Aerial view of field.
Historic Environment Scotland

Historic Environment Scotland has a team of aerial surveyors trained to spot the clues: To date, they've discovered more than 9000 archaeological sites from the air. HSE plans to continue scoping out new areas of interest as long as the dry spell lasts.

It's not just in Scotland that long-hidden settlements are coming to light: similar aerial surveys in Wales are finding them too.

[h/t BBC]

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Billion-Year-Old Rocks Reveal the First Color Ever Produced by a Living Thing
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iStock

Billions of years ago, before there were plants and animals on Earth, there were rocks, tiny organisms, water, and not much else. It’s hard to envision what our barren planet looked like back then, but scientists now have some idea of what colors dominated the landscape.

As Vice reports, a team of researchers from Australian National University (ANU) were able to pinpoint the oldest colors ever produced by a living creature: purple-red hues dating back more than 1.1 billion years. The pigments, which appear pink when diluted, were found in molecular fossils of chlorophyll that had been preserved in rocks beneath the Sahara desert. A billion years ago, though, this area was “an ancient ocean that has long since vanished,” Nur Gueneli of ANU said in a statement.

Chlorophyll may very well be green, but these pinkish pigments are a result of "fossilized porphyrins, a type of organic compound that forms an atomic ring around a magnesium ion to form a chlorophyll molecule," Vice explains.

While this provides an interesting visual, the color itself is less important than what it reveals about some of the earliest life forms on Earth. Scientists determined that the chlorophyll was produced by ancient organisms called cyanobacteria, which derived energy via photosynthesis and ruled the oceans at that time, researchers wrote in a paper published in the Proceedings of the National Academy of Sciences. Larger planktonic algae—a potential food source for bigger life forms— were scarce, which may explain why large organisms didn’t roam the Earth a billion years ago. That kind of algae was about a thousand times larger than the cyanobacteria.

“The cyanobacterial oceans started to vanish about 650 million years ago, when algae began to rapidly spread to provide the burst of energy needed for the evolution of complex ecosystems, where large animals, including humans, could thrive on Earth," ANU associate professor Jochen Brocks said.

So the next time you encounter algae, you can thank it for helping you secure a spot on this planet.

[h/t Vice]

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