When the last Ice Age ended and the glaciers retreated, roughly 11,000 years ago, something appears to have changed among the wild grapevines of Asia. They became domesticated. The first farmers on Earth began cultivating the best vines with the biggest, juiciest grapes.
In the process, researchers came across previously undocumented cultivars growing in old vineyards, a find that allowed the discoverers to name these overlooked or forgotten grape varieties.
The new work reinforces archaeological evidence that the development of agriculture was accompanied by abundant fermented beverages.
“The grapevine was probably the first fruit crop domesticated by humans,” senior author Wei Chen, an evolutionary biologist at Yunnan Agricultural University, said in a media briefing Thursday.
The research carried a geopolitical message as well, showing scientific cooperation at its best amid turbulent times.
“I think our collaboration shows that we can achieve big things, just like the ancient people that traded grapes across borders,” Chen said in an interview with The Washington Post.
Chen said that scientists in many nations had long explored when people began tinkering with wild grapevines to take advantage of the ones that produced the best fruit. But earlier studies had been done in isolation and often contradicted one another on the difficult question. Some estimates put domestication as far back as 15,000 years ago, well in advance of the development of agriculture.
Chen persuaded colleagues from across Europe and Asia to collaborate, creating a genomic database from vines across a vast region, from the Iberian Peninsula to Japan.
“We joined forces and looked into what’s really going on with grape evolution and grapevine domestication,” Chen said.
There are many species of grapevines, but only one, Vitis vinifera, supplies the wine that is recommended by a sommelier. The familiar grapes that segment the wine market — merlot, cabernet sauvignon, pinot noir — are varietals of that species.
“We care about this grape so much we gave each variety a specific name,” Chen said. “We don’t do it for, like, wheat or barley.”
There are still wild grapes with an ancient lineage, of the subspecies sylvestris. They tend to produce small grapes, few in number and bitter, but they’re valuable to modern society because they contain genes that offer resistance to diseases and climate change, said Peter Nick, a co-author of the new study and a plant biologist at the Karlsruhe Institute of Technology in Germany.
“These wild grapes and these very old varieties still have these resilience genes, which we will need to render the grape resistance against the challenge of climate change,” Nick said.
Research into grape domestication has long been dominated by archaeologists, who tell the story of that era through seeds and traces of wine in broken pottery. The people of prehistory had not yet invented writing, so the wine drinkers of 10 millennia ago did not leave behind vintage ratings or recommendations for which wine would pair nicely with roasted goat.
Genomic analysis represents a relatively new technique for penetrating the fog of prehistory — a period when the postglacial climate warmed, humans increased in number and cultures flourished.
Domesticated grapes are hermaphroditic and can fertilize themselves. The analysis of modern plants and their genetic history showed a change in the gene flow about 11,000 years ago that signaled a selection by early farmers for hermaphroditic grapevines.
But the new report has come up with a surprising twist on the story: Domestication happened twice, on different lineages of the wild grapes.
Both events occurred around the same time, one in the Caucasus region that includes modern-day Armenia, Georgia and Azerbaijan, and one in western Asia. The two regions are more than 600 miles apart. Chen noted that human migration, or cultural exchanges, could explain the two separate domestications. In other words, good ideas get around.
The study authors believe that the Caucasus line of grapevines gave rise to the ones selected for their winemaking potential, while the west Asian lineage was initially selected as a food source — table grapes. Surprisingly, those table grapes were then intermixed with wild grapes to create the wine-producing grapes found across much of western Asia and Europe, including the famous wine regions along the Mediterranean.
The analysis can’t answer the question of when people started fermenting grapes routinely to create wine, Nick said. But starting about 11,000 years ago, he said, “people deliberately were growing vines, and not just collecting the berries in the forest.”
Archaeological evidence places the earliest-known winemaking about 8,000 years ago in what is now Georgia, in the Caucasus. And grapevine varieties were clearly carried great distances, eventually leading to the profusion of wine varieties enjoyed by modern oenophiles.
“It was one of the first globally traded goods. It’s justified to say that the domestication of grapevines was really one of the driving forces of civilization,” Nick said.
But Patrick McGovern, a biomolecular archaeologist at the University of Pennsylvania Museum and author of the book “Ancient Wine,” said in an email that the new research falls short of proving that people had domesticated grapevines 11,000 years ago.
“Utilizing and even ‘cultivating’ wild grapes for food and drink is one thing, but actually ‘domesticating’ the grape is something altogether different and much more difficult,” McGovern said in an email. “For that, convincing archaeological, archaeobotanical, and/or chemical evidence is needed.”
He said the domestication of grapevines requires extensive horticultural skill.
“The combination of technological hurdles to be overcome in ‘domesticating’ the grapevine or any fruit plant may explain why of all the many grape species that grow worldwide … only the Eurasian grapevine (Vitis vinifera), on current evidence, was domesticated in antiquity,” he said.