6 millennia old but ‘almost fresh,’ Masada seeds unravel barley’s origins

Grains found in Judean Desert, the oldest plant DNA ever sequenced, point to cereal’s domestication in Jordan Valley, scientists say

Ilan Ben Zion is an AFP reporter and a former news editor at The Times of Israel.

Palestinians harvest wheat and barley in a field near the West Bank city of Hebron, May 06, 2016. (Wisam Hashlamoun/Flash90)
Palestinians harvest wheat and barley in a field near the West Bank city of Hebron, May 06, 2016. (Wisam Hashlamoun/Flash90)

A new study has allowed scientists to peer thousands of years back in time via a grain of barley found in the Judean Desert.

Barley seeds, dated to 6,000 years ago, have become the oldest plant genome to be sequenced, an international team of researchers announced in a journal article published Monday. Analysis of the 6,000-year-old cereals supports the hypothesis that the key crop was domesticated thousands of years ago in the Jordan Valley.

A team of scientists from Israel, Germany, the United Kingdom and the US employed a wide array of disciplines — archaeology, archaeobotany and genetics — to study the material found in the Yoram Cave. The findings were released in the academic journal Nature Genetics.

The Chalcolithic kernels were discovered in a cavern overlooking the Dead Sea on the southern end of Masada, a mountaintop better known for Jewish rebels’ last stand against the Roman Empire in the first century CE.

The arid climate and precipitous cliff left the grains preserved for millennia. Ehud Weiss of Bar-Ilan University, one of the heads of the study, told The Times of Israel that whereas most ancient kernels are found charred and useless for DNA study, those excavated from the cave on Masada by a Hebrew University team “looked almost alive, almost fresh.”

Their immaculate preservation allowed scientists to “read the DNA from these seeds” and determine that they were domesticated locally, he said.

Weiss said that the barley found at Masada could only have been grown at least 20 kilometers (12 miles) from the remote mesa. Hebrew University archaeologist Uri Davidovitch posited that the people who brought it to the cave may have fled some unknown catastrophe and sought refuge in the desert, just like the mountaintop’s Jewish inhabitants thousands of years later.

An aerial view of Masada (photo credit: Shmuel Bar-Am)
An aerial view of Masada (photo credit: Shmuel Bar-Am)

Radiocarbon dating determined the seeds were 6,000 years old, grown several millennia after humans residing in the Fertile Crescent first domesticated grains such as barley and wheat around 10,000 years ago.

Until now, corn was the only ancient grain whose genetic fingerprint was fully mapped out. Barley’s genome was only studied through modern samples.

The seeds found in at Masada are “much closer to the time and place of domestication,” Weiss said. They are a “time capsule” that gives scientists a shortcut around 6,000 years of genetic mutation and offers insight into what the ancients ate.

Sequencing prehistoric barley is “just the beginning of a new and exciting line of research,” Verena Schuenemann of Tubingen University, one of the heads of the study, said.

Examination of the barley grains’ genome found they are significantly different from wild varieties, but similar to modern cultivars still grown in the region. The finding bolsters the hypothesis that barley was domesticated in the Jordan Valley, researchers said.

Last year a study by researchers from Tel Aviv University, Harvard University and Bar Ilan found cultivated plants in the Galilee dating back 23,000 years, pushing back the origins of domesticated crops at least 11,000 years.

A study published in 2015 said genetic analysis of barley varieties pointed to domestication of the grain occurring at several points across the Mideast in prehistory.

“DNA-analysis of archaeological remains of prehistoric plants will provide us with novel insights into the origin, domestication and spread of crop plants,” Schuenemann said in a statement.

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