The American scientist Dr. Carole P. Meredith had been working at the University of California in Davis since 1980. There she taught as a professor for viticulture and cellar management and was intensively engaged in ampelographic tasks. From the mid-1990s onwards, she made very successful efforts to determine the origin of grape varieties by DNA analysis. There was close collaboration with the French research institute in Montpellier, especially with the Swiss ampelographer Jean-Michel Boursiquot. Among other things, the parentage of the varieties Cabernet Sauvignon, Carmenère, Charbono, Chardonnay, Durif, Gamay, Merlot, Merlot Blanc, Plavac Mali, Syrah and Zinfandel (or that it is identical to Primitivo and Tribidrag), as well as more than 20 crosses of Gouais Blanc x Pinot were clarified.