BBC Science's Toby Murcott: "Grapes' distant relationship key to success"

Scientists have used DNA fingerprinting to prove that sixteen varieties, including Chardonnay, all stem from a union between the classic Pinot Noir and an obscure grape called Gouais.

The discovery by Carole Meredith and John Bowers from the University of California, Davis, will help avoid in-breeding between grape varieties.

Strong family links

Traditionally, grapevine varieties have been identified by physical features of their leaves and fruit. But these traits can vary according to environmental conditions.

Pinot Noir: Proud parent

In recent years DNA fingerprinting, which compares characteristic patterns in the genetic material of the plant, has proved to be a highly accurate way of identifying varieties no matter where they are growing.

Analysis of leaf samples from 300 varieties kept by the Institut de la Recherche Agronomique near Montpellier showed strong family links.

Further study of 60 samples revealed that 16 appear to come from just two ancient varieties - Pinot Noir and Gouais Blanc.

Grape spurned in Middle Ages

Chardonnay: Offspring of the Gouais

The results came as a surprise for wine experts. A genetic link had been suspected between Pinot Noir and Chardonnay, the noble red and white grapes of the Burgundy and Champagne regions of north-eastern France.

But the Gouais grape has been regarded as awful for centuries. Unsuccessful attempts were made to ban it from vineyards as far back as the Middle Ages, and it is no longer planted in France.

Even the name stems from an old French word "gou" - a term of derision.

The Gouais vine has a high yield of white grapes. Pinot Noir produces far less fruit, but of a higher quality.

Strength in diversity

Genetic differences create robust wines

According to Professor Meredith, the unlikely success of the union between Pinot Noir and the disdained Gouais may arise from their differences.

"Gouais and Pinot have been successful parents because of their genetic diversity," said Professor Meredith.

"We now know you would never want to cross Chardonnay and Pinot, because you'd be more likely to get physically weak progeny, similar to in-breeding problems which occur when closely related people marry."

As well as being historically intriguing, the discovery has practical implications for conserving grape varieties.

The entire gene pool of all 16 grape types can be preserved just by keeping the Pinot and Gouais varieties.

The research is published in the journal Science.