DNA was examined in a recent study conducted by the University of Haifa and the Steinhardt Museum of Natural History Paleogenetic Laboratory at Tel Aviv University using ancient wine grape seeds found in the Negev.
Another seed is a relative of the white variety known as Be’er, which is still growing in abandoned vineyards in the dunes of Palmachim. One seed was discovered to be practically identical to the Syriki variety, which is used today to produce high-quality red wine in Greece and Lebanon.
Exported to Europe
Dr. Pnina Cohen and Dr. Meirav Meiri of the paleogenetic lab at the Steinhardt Museum of Natural History at Tel Aviv University led the genetic study. In cooperation with archaeologists from the Israel Antiquities Authority, Prof. Guy Bar-Oz of the School of Archaeology and Maritime Cultures at the University of Haifa supervised archaeological digs where the seeds were discovered.
Other participants included researchers from the University of Haifa, the Weizmann Institute, Bar-Ilan University, and research institutions in France, Denmark, and the U.K. The paper was published in the journal Proceedings of the National Academy of Sciences.
“Archaeological excavations conducted in the Negev (in Israel) in recent years have revealed a flourishing wine industry from the Byzantine and early Arab periods (around the fourth to ninth centuries A.D.), especially at the sites of Shivta, Haluza, Avdat, and Nizana, which were large, thriving cities at the time,” says Prof. Guy Bar-Oz from the University of Haifa.
“The findings include large winepresses, jugs in which the exclusive wine, exported to Europe, was stored, and grape seeds preserved for more than a thousand years. This industry gradually declined following the Muslim conquest in the 7th century, since Islam forbids the consumption of wine.”
“The cultivation of wine grapes in the Negev was renewed only in modern times, in the state of Israel, mostly since the 1980s. This industry, however, relies mainly on wine grape varieties imported from Europe.”
We believe that our findings are also significant for Israel’s modern wine industry, which has been growing and thriving in recent decades. Today, most varieties grown here have been imported from Europe, so that the local conditions are not optimal for them. Local varieties can be more suitable for the local climate and soil, especially in the desert region of the Negev. Our study opens new paths for restoring and improving ancient local varieties, to create wine grapes that are more suitable for challenging climatic conditions such as high temperatures and little rainfall.
Dr. Meirav Meiri
Extracting DNA
At Avdat, a sizable cache of grape seeds was found on the floor of a sealed compartment, and it was one of the more intriguing discoveries. According to the experts, these seeds have been remarkably well maintained since they have been shielded from environmental calamities like excessive heat, flooding, or dehydration.
The researchers planned to extract the seeds’ DNA in the paleogenetic lab in order to learn more about them and determine which variety they may belong to.
“The science of paleogenomic uses a range of advanced technologies to analyze ancient genomes, primarily from archaeological findings,” explains Dr. Meiri from the Steinhardt Museum of Natural History at Tel Aviv University.
“Since the DNA molecule is very sensitive and disintegrates over time, especially under high temperatures, we usually get only small pieces of DNA, often in a poor state of preservation. To protect them we work under special conditions: the paleogenetic lab is an isolated clean laboratory, with positive air pressure that keeps contaminants out, and we enter it in sterilized ‘spacesuits’ familiar to everyone from the COVID pandemic.”
To begin with, the researchers looked for any organic matter remaining in the seeds. They achieved this using Fourier-transform infrared spectroscopy (FTIR), a chemical method that uses infrared radiation to produce a light spectrum that reveals the composition of the material. The researchers extracted DNA from 16 seeds after discovering traces of organic materials.
Ancient grapes: Still around today
With a focus on around 10,000 genomic locations where variety-specific traits are typically present, the extracted DNA was sequenced, and the results were compared to databases of contemporary grapevines from throughout the world: The genetic material in 11 samples was of insufficient quality to support any firm conclusions.
Three of the remaining samples were identified as generally belonging to local varieties. Finally, the two samples of the highest quality, both from around 900 A.D., were identified as belonging to specific local varieties that still exist today.
The discovery was quite extraordinary:
One of the seeds was identified as Syriki, a well-known Middle Eastern variety with a long history of cultivation in the Southern Levant and Crete that is still used today in Greece (where it is believed to have originated from the east) and Lebanon to produce premium red wine. It is extremely plausible that the name Syriki is derived from Nahal Sorek, an important stream in the Judean Hills, as wine grapes are typically named by their location of origin. Moreover, this variety may even appear in the Bible in Jacob’s blessing to his son Judah: “He will tether his donkey to a vine, his colt to the choicest branch (soreka); he will wash his garments in wine, his robes in the blood of grapes (Genesis 49, 11); and perhaps also suggested in the giant cluster of grapes brought back by the men sent by Moses to explore the land: “When they reached the Valley of Eshkol (identified by some as Nahal Sorek), they cut off a branch bearing a single cluster of grapes. Two of them carried it on a pole between them.”
The other high-quality seed was identified as related to Be’er, a white wine grape variety still growing in the sands of Palmachim on Israel’s seashore, in remnants of vineyards probably abandoned in the mid-20th century.
It was the oldest botanical example of a white variety ever identified. The researchers were able to utilize the genome of a grape seed for the first time to determine the color of the fruit. Be’er, a unique local variety, endemic to the land of Israel, is used today by the Barkan winery to make a special white wine of its own.
Tiny items tell a big story
“The wonderful thing about paleogenetics is that sometimes, tiny items can tell a big story,” says Dr. Meiri. “This is exactly what happened in this study. With just a bit of DNA extracted from two grape seeds we were able to trace continuity in the local wine industry from the Byzantine period, more than a thousand years ago, to the present day.”
“We believe that our findings are also significant for Israel’s modern wine industry, which has been growing and thriving in recent decades. Today, most varieties grown here have been imported from Europe, so that the local conditions are not optimal for them. Local varieties can be more suitable for the local climate and soil, especially in the desert region of the Negev. Our study opens new paths for restoring and improving ancient local varieties, to create wine grapes that are more suitable for challenging climatic conditions such as high temperatures and little rainfall.”
