In vino veritas--plenty of secrets have tumbled from lips loosened by wine. Now, wine grapes themselves are spilling some secrets. Scientists have used DNA fingerprinting to decipher the pedigree of some of the world's most renowned grapevine varieties. Some 16 of them, it turns out, are the offspring of a single, highly prolific pair of parents: Pinot, the epitome of a fine Burgundy, and, surprisingly, Gouais blanc, an obscure white variety that was banned throughout France in the 1950s due to the poor quality of its wine.
The study, published in tomorrow's Science, is "quite a shocker," says grape geneticist Bruce Reisch of Cornell University's New York State Agricultural Experiment Station in Geneva. "No one would have imagined that all [these varieties] are from the same parents."
In the early 1990s, Australian geneticists developed a system to distinguish grape cultivars based on their so-called microsatellites--simple, repetitive sequences of DNA that vary in length between unrelated individuals and thus create a genetic "fingerprint." Plant geneticist Carole Meredith and her colleague John Bowers at the University of California, Davis, used the method to see if they could find the hidden family ties among 322 French grape varieties. Aided by a computer program Bowers developed for spotting shared microsatellite patterns in the cultivars, the researchers were able to construct what amounted to a Burgundy family tree, tracing the relationships of 18 varieties from that region. Pinot and Gouais blanc appeared to be the likely founders of the Burgundian line. Because most, if not all, of the 16 siblings predate the times of deliberate grapevine breeding by hundreds of years, Meredith says the various crosses must have occurred spontaneously--and independently--by cross-pollination between Pinot and Gouais vines, most likely somewhere in northeastern France.
For wine purists, especially in France where new hybrid grape varieties are legally excluded from bearing the prestigious designation, "Appellation d'Origine Controllée" (AOC), the findings might be rather disconcerting. Says Alain Bouquet, a grape breeder at the Institut National de la Recherche Agronomique near Montpellier, France, "The AOC system from 1934 was based on the assumption that varieties obtained by crossing are inferior to the traditional varieties. I think this is erroneous in the case of crosses between old European grapes, as it is now proven that the two best varieties in the world, Cabernet Sauvignon and Chardonnay, are derived from such crosses."