Seeds that provide a genetic link between two modern varieties of red and white grapes cultivated over 1,100 years ago – and apparently were mentioned in two different books of the Bible – have resulted in an “extraordinary and thrilling discovery” by archaeologists at Tel Aviv University (TAU) and the University of Haifa.
“One ancient seed was found to belong to the Syriki variety, still used to make high-quality red wine in Greece and Lebanon. Since winegrapes are usually named after their place of origin, it is quite possible that the name Syriki is derived from Nahal Sorek, an important stream in the Judean Hills. A second seed was identified as related to the Be’er variety of white winegrapes still growing in the sands of Palmachim on the Mediterranean seashore.”
The new study was led by the paleogenomic laboratory of TAU’s Steinhardt Museum of Natural History and the University of Haifa analyzed DNA from ancient local winegrape seeds discovered at archaeological excavations in the Negev.
What did they find?
The genetic study was led by TAU’s Dr. Pnina Cohen and Dr. Meirav Meiri. The seeds were found at archaeological excavations led by Prof. Guy Bar-Oz and colleagues from the University of Haifa’s School of Archaeology and Maritime Cultures, in collaboration with researchers from the Israel Antiquities Authority.
Other participants included researchers the Weizmann Institute of Science in Rehovot, Bar-Ilan University in Ramat Gan, together with research institutions in France, Denmark and the UK. The paper has just been published in the leading scientific journal PNAS under the title “Ancient DNA from a lost Negev Highlands desert grape reveals a Late Antiquity wine lineage.”
They said the first 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 of Israel: “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” (Numbers 13, 23).
Bar-Oz noted that “archaeological excavations conducted in the Negev in recent years have revealed a flourishing wine industry from the Byzantine and early Arab periods (around the 4th to 9th centuries CE, especially at the sites of Shivta, Haluza, Avdat and Nizana, which were large, thriving cities at the time. The findings include large winepresses, jugs in which the exclusive wine exported to Europe was stored and grape seeds preserved for more than 1,000 years."
He added that this industry “gradually declined following the Muslim conquest in the 7 th century, since Islam forbids the consumption of wine. The cultivation of winegrapes in the Negev was renewed only in modern times, in the State of Israel, mostly since the 1980s. This industry, however, relies mainly on winegrape varieties imported from Europe.”
One especially interesting finding was a large hoard of grape seeds, discovered on the floor of a sealed room at Avdat. The researchers explain that these seeds have been relatively well-preserved thanks to protection from climatic phenomena such as extreme temperatures, flooding, or dehydration. In the hope of discovering which varieties the seeds might belong to, the researchers prepared to extract their DNA in the paleogenetic lab.
“The science of paleogenomic uses a range of advanced technologies to analyze ancient genomes, primarily from archaeological findings. 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,” Meiri explained. “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.”
The researchers first looked for any organic matter remaining in the seeds by using FTIR (Fourier-transform infrared spectroscopy) – a chemical technique applying infrared radiation to produce a light spectrum that identifies the sample's content. Finding remnants of organic matter in 16 seeds, they went on to extract DNA from the samples.
The extracted DNA was sequenced, with an emphasis on about 10,000 genomic sites where variety-specific features are usually found; the results were compared to databases of modern grapevines from around the world. In 11 samples, the quality of genetic material was too poor to allow any definite conclusions, but 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 CE, were identified as belonging to specific local varieties that still exist today. The other high-quality seed identified as related to Be’er, a white winegrape variety still growing in the sands of Palmachim in remnants of vineyards probably abandoned in the mid- 20 th century. For the first time ever, the researchers were able to use the genome of a grape seed to determine the color of the fruit, discovering that it was in fact a white grape – the oldest botanical specimen of a white variety ever identified.
Be'er, a unique local variety native to the Land of Israel, is used today by the Barkan winery to make a special white wine of its own. “The wonderful thing about paleogenetics is that sometimes, tiny items can tell a big story. This is exactly what happened in our 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 1,000 years ago, to the present day,” Meiri concluded.
“We believe 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 Negev. Our study opens new paths for restoring and improving ancient local varieties, to create winegrapes that are more suitable for challenging climati conditions such as high temperatures and little rainfall,” she said.