Why Did Ancient Europeans Just Disappear 14,500 Years Ago?

Some of Europe's earliest inhabitants mysteriously vanished toward the end of the last ice age and were largely replaced by others, a new genetic analysis finds.

The finds come from an analysis of dozens of ancient fossil remains collected across Europe.

The genetic turnover was likely the result of a rapidly changing climate, which the earlier inhabitants of Europe couldn't adapt to quickly enough, said the study's co-author, Cosimo Posth, an archaeogenetics doctoral candidate at the University of Tübingen in Germany.

The temperature change around that time was "enormous compared to the climactic changes that are happening in our century," Posth told Live Science. "You have to imagine that also the environment changed pretty drastically."

A twisted family tree

Europe has a long and tangled genetic legacy. Genetic studies have revealed that the first modern humans who poured out of Africa, somewhere between 40,000 and 70,000 years ago, soon got busy mating with local Neanderthals. At the beginning of the agricultural revolution, between 10,000 and 12,000 years ago, farmers from the Middle East swept across Europe, gradually replacing the native hunter-gatherers. Around 5,000 years ago, nomadic horsemen called the Yamnaya emerged from the steppes of Ukraine and intermingled with the native population. In addition, another lost group of ancient Europeans mysteriously vanished about 4,500 years ago, a 2013 study in the journal Nature Communications found.

But relatively little was known about human occupation of Europe between the first out-of-Africa event and the end of the last ice age, around 11,000 years ago. During some of that time, the vast Weichselian Ice Sheet covered much of northern Europe, while glaciers in the Pyrenees and the Alps blocked east-west passage across the continent.

Lost lineages

To get a better picture of Europe's genetic legacy during this cold snap, Posth and his colleagues analyzed mitochondrial DNA — genetic material passed on from mother to daughter — from the remains of 55 different human fossils between 35,000 and 7,000 years old, coming from across the continent, from Spain to Russia. Based on mutations, or changes in this mitochondrial DNA, geneticists have identified large genetic populations, or super-haplogroups, that share distant common ancestors.

"Basically all modern humans outside of Africa, from Europe to the tip of South America, they belong to these two super-haplogroups that are M or N," Posth said. Nowadays, everyone of European descent has the N mitochondrial haplotype, while the M subtype is common throughout Asia and Australasia.

The team found that in ancient people, the M haplogroup predominated until about 14,500 years ago, when it mysteriously and suddenly vanished. The M haplotype carried by the ancient Europeans, which no longer exists in Europe today, shared a common ancestor with modern-day M-haplotype carriers around 50,000 years ago.

The genetic analysis also revealed that Europeans, Asians and Australasians may descend from a group of humans who emerged from Africa and rapidly dispersed throughout the continent no earlier than 55,000 years ago, the researchers reported Feb. 4 in the  journal Current Biology.

Time of upheaval

The team suspects this upheaval may have been caused by wild climate swings.

At the peak of the ice age, around 19,000 to 22,000 years ago, people hunkered down in climactic "refugia," or ice-free regions of Europe, such as modern-day Spain, the Balkans and southern Italy, Posth said. While holdouts survived in a few places farther north, their populations shrank dramatically.

Then around 14,500 years ago, the temperature spiked significantly, the tundra gave way to forest and many iconic beasts, such as woolly mammoths and saber-toothed tigers, disappeared from Eurasia, he said.

For whatever reason, the already small populations belonging to the M haplogroup were not able to survive these changes in their habitat, and a new population, carrying the N subtype, replaced the M-group ice-age holdout, the researchers speculate.

Exactly where these replacements came from is still a mystery. But one possibility is that the newer generation of Europeans hailed from southern European refugia that were connected to the rest of Europe once the ice receded, Posth speculated. Emigrants from southern Europe would also have been better adapted to the warming conditions in central Europe, he added.
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Reference:

Ghose, Tia. 2016. “Why Did Ancient Europeans Just Disappear 14,500 Years Ago?”. Live Science. Posted: March 1, 2016. Available online: http://www.livescience.com/53883-ancient-europeans-vanished-after-ice-age.html

Oldest European fort in the inland US discovered in Appalachians

The remains of the earliest European fort in the interior of what is now the United States have been discovered by a team of archaeologists, providing new insight into the start of the U.S. colonial era and the all-too-human reasons spoiling Spanish dreams of gold and glory.

Spanish Captain Juan Pardo and his men built Fort San Juan in the foothills of the Appalachian Mountains in 1567, nearly 20 years before Sir Walter Raleigh's "lost colony" at Roanoke and 40 years before the Jamestown settlement established England's presence in the region.

"Fort San Juan and six others that together stretched from coastal South Carolina into eastern Tennessee were occupied for less than 18 months before the Native Americans destroyed them, killing all but one of the Spanish soldiers who manned the garrisons," said University of Michigan archaeologist Robin Beck.

Beck, an assistant professor in the U-M Department of Anthropology and assistant curator at the U-M Museum of Anthropology, is working with archaeologists Christopher Rodning of Tulane University and David Moore of Warren Wilson College to excavate the site near the city of Morganton in western North Carolina, nearly 300 miles from the Atlantic Coast.

The Berry site, named in honor of the stewardship of landowners James and the late Pat Berry, is located along a tributary of the Catawba River and was the location of the Native American town of Joara, part of the mound-building Mississippian culture that flourished in the southeastern U.S. between 800 and about 1500 CE.

In 2004, with support from the National Geographic Society and the National Science Foundation, Beck and his colleagues began excavating several of the houses occupied by Spanish soldiers at Joara, where Pardo built Fort San Juan. Pardo named this small colony of Spanish houses Cuenca, after his own hometown in Spain. Yet the remains of the fort itself eluded discovery until last month.

"We have known for more than a decade where the Spanish soldiers were living," Rodning said. "This summer we were trying to learn more about the Mississippian mound at Berry, one that was built by the people of Joara, and instead we discovered part of the fort. For all of us, it was an incredible moment."

Using a combination of large-scale excavations and geophysical techniques like magnetometry, which provides x-ray-like images of what lies below the surface, the archaeologists have now been able to identify sections of the fort's defensive moat or ditch, a likely corner bastion and a graveled surface that formed an entryway to the garrison.

Excavations in the moat conducted in late June reveal it to have been a large V-shaped feature measuring 5.5 feet deep and 15 feet across. Spanish artifacts recovered this summer include iron nails and tacks, Spanish majolica pottery, and an iron clothing hook of the sort used for fastening doublets and attaching sword scabbards to belts.

Fort San Juan was the first and largest of the garrisons that Pardo founded as part of an ambitious effort to colonize the American South. Pedro Menéndez de Avilés, who had established the Spanish colonies of St. Augustine and Santa Elena in 1565 and 1566, respectively, spearheaded this effort. Of the six garrisons that Pardo built, Fort San Juan is the only one to have been discovered by archaeologists.

During the brief time the Spaniards were at Joara, Beck says, they were actively prospecting for gold but never found it. Yet the gold was there: in the early 1800s, American settlers found so much just lying on the surface near rivers that a 17-pound gold nugget was used as a doorstop and a U.S. mint was established in Charlotte, triggering the first gold rush in U.S. history.

Had the people of Joara given Pardo's soldiers more time to discover this gold, Spain would probably have launched a full-scale colonial invasion of the area, England would have had difficulty establishing its foothold at Jamestown, and the entire southeastern part of what is now the U.S. might instead have become part of Latin America.

Why did the Mississipians wipe the Spaniards out so quickly? Beck and colleagues argue that originally, the Spanish bartered with the natives for food.

"The soldiers believed that when their gifts were accepted, it meant that the native people were their subjects," Beck said. "But to the natives, it was simply an exchange. When the soldiers ran out of gifts, they expected the natives to keep on feeding them. By that time, they had also committed what Spanish documents refer to as "indiscretions" with native women, which may have been another reason that native men decided they had to go. So food and sex were probably two of the main reasons for destroying Spanish settlements and forts."

Moore said the significance of Fort San Juan extends far beyond the Carolina Piedmont.

"The events at Fort San Juan represent a microcosm of the colonial experience across the continent," he said. "Spain's failure created an opening that England exploited at Jamestown in 1607, when America's familiar frontier narrative begins. For Native Americans, though, this was the beginning of a long-term and often tragic reshaping of their precolonial world."
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References:

EurekAlert. 2013. “Oldest European fort in the inland US discovered in Appalachians”. EurekAlert. Posted: July 23, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-07/uom-oef072313.php