The domestication of table grapes and that of wine were domesticated simultaneously, 11,000 years ago, with the advent of agriculture. This is determined by a survey with the largest genetic sample of vine plants collected to date from different geographical areas.
Despite the fact that wine and grapes played a very important role in cultivation, the truth is that until now it was difficult to confirm when the vine was domesticated and where it happened. One of the reasons is that sufficiently thorough genetic sequencing analyzes of the grape varieties had not been carried out.
An international team of researchers carried out this genetic study, the largest to date carried out on different grape varieties, which includes samples from hitherto undocumented specimens in private collections.
The work, which was done with the added difficulty of covid-19 lockdowns and restrictions, provides new insights into how, when and where vines for wine and table grapes were domesticated.
Until now, certain hypotheses pointed out that the cultivated vine (Vitis vinifera) had had only one domestication in West Asia. It was believed that all varieties of wine came from it and that it was domesticated before the advent of agriculture. Another hypothesis that turned out to be true was that vines for wine were older than vines for table grapes.
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Dismantled theories on the domestication of grapes
This study, published in the journal Science and led by Yang Dong and his team, would dismantle both theories. Their work describes that there were two events of vine domestication in two different locations, West Asia and the Caucasus region, separated during the last glacial advance.
In a related article, Robin Allaby of the University of Warwick explains: “Despite being more than 1000 kilometers apart, both domestication processes appear to have occurred simultaneously with a high degree of shared selection signatures on the same genes.
The researchers also showed that the two events happened simultaneously, shattering the thesis that the wine vine was cultivated first. According to their findings, they occurred 11,000 years ago, with the beginnings of agriculture, and some 4,000 years later than some earlier studies showed.
“Whether table grapes or wine grapes came first is a question arising from the initial belief of a single domestication event. We now know that the original belief is no longer true. With two domestication events, there is a third possibility, that both types of grapes came out at the same time. And that’s exactly what the scans showed“Says Wei Chen, co-author of the study.
To determine this timeline and calculate when the events took place, they used the estimate of the relative rate of cross coalescence (RCCR), which indicates when two populations divide.
“In our case, the process of domestication can be seen as the population of cultivated grapes separating from its wild ancestral population. Therefore, we use RCCR to derive the time of domestication, and the estimate for both events dates back to about 11,000 years ago, meaning they happened at the same time in the past.Chen points out.
a great sample
The authors generated a high-quality reference genome at the chromosomal scale of the wild grape ancestor. Vitis sylvestre. Subsequently, they sequenced more than 3,000 individual samples of grapevine plants collected from a wide range of locations around the world, including wild specimens and private collections.
“It is the largest collection of wild and cultivated vines to date, covering all of the former’s growing areas and the major latter’s growing areas in the world.“, precise.
Chen acknowledges that, thanks to his collaborators, they were able to obtain old and local varieties. For example, many of these samples from ancient vineyards in Armenia turned out to be undocumented varieties.
For research, they used samples from countries such as Japan, Korea, India, Pakistan, Afghanistan, Turkmenistan, Kyrgyzstan, Uzbekistan, Kazakhstan, Azerbaijan, Iran , Dagestan (Russia), Georgia, Yemen, Syria, Lebanon, Jordan, Israel, Egypt. , Cyprus, Turkey, Bulgaria, Romania, Ukraine, Moldova, Serbia, Hungary, Greece, Albania, Croatia, Montenegro, Czech Republic, Germany, Austria, Slovenia, Italy, Tunisia, Algeria, Australia, South Africa, Argentina, United United, United Kingdom, Switzerland, France but also from the Iberian Peninsula, including Spain and Portugal.
The study also found that wine grapes in Europe come from domesticated table grapes in West Asia. “The process involves crossing table grapes with local wild grapes, since the first farmers traveled to Europe to settle,” Chen adds.
Characteristics of white grapes
Thanks to the study, it was possible to identify certain genes involved in the domestication of grapes – which improve flavor, color and texture – which could help winemakers improve wine today and make varieties more resilient to climate change and other stresses.
Among their findings, they uncovered more details about the genetics behind the color of white grapes and the ancient flavor of muscat. As they state, at least one allele underlying muscat flavor may be detrimental to plant health.
“Desirable traits are often linked to genetic variations. These are rare in a population at first, and as people select them, they become more and more important. If all goes well, everyone gets two copies of the variations“, Chen said.
“In muscat grapes, most varieties ended up with a single copy of a variation associated with the flavor trait. This implies that two variations may be too many for one grape variety. Unfortunately, we do not know the molecular mechanism of this observation.” he concludes.
Could there have been more than two events in the domestication of grapes?
Although the study speaks of two grape domestication events, it does not close the door to the fact that there could be more. The team has raised a third that they want to explore.
“We need to analyze a region of Central Asia (Fergana Valley) in the future. Unfortunately, we could not test if this place is a third center of domestication, because we need reliable wild grapes from this region.“concludes the researcher.
Reference:
Yang Dong et al. “Largest-ever genetic analysis of vine varieties reveals how glacial cycles shaped the domestication of grapes and the rise of wine.” Science.
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