From the New York Times:
For the last 8,000 years, the wine grape has had very little sex. This unnatural abstinence threatens to sap the grape’s genetic health and the future pleasure of millions of oenophiles.
The lack of sex has been discovered by Sean Myles, a geneticist at Cornell University. He developed a gene chip that tests for the genetic variation commonly found in grapes. He then scanned the genomes of the thousand or so grape varieties in the Department of Agriculture’s extensive collection.
Much to his surprise he found that 75 percent of the varieties were as closely related as parent and child or brother and sister. “Previously people thought there were several different families of grape,” Dr. Myles said.