After looking at at 9,000 genetic markers in 583 different grape varieties, Sean Myles, a genetic researcher at Cornell University, discovered that the 75 percent of the grapes winemakers grow are close cousins who, frankly, don’t have a lot of sex. His study was published in the January issue of the Proceeding of the National Academy of Science.

Since grapes were domesticated, plant breeders and wine growers have essentially been reusing the same varieties over and over, planting cloned vines, in an attempt to preserve the flavor that, say, a Merlot drinker expects (which is not the flavor of a Merlot grape crossed with a Chardonnay). The New York Times reports that the practice is not without trade-offs.