Chemical modifications to grape genes may be responsible for some of the subtle differences between one bottle and the next.
Connoisseurs have long attributed a wine’s qualities to its DNA and its ‘terroir’ — the interaction of factors such as genetics, farming practices and environmental variables, like a vineyard’s soils. Carlos Lopez at the University of Adelaide in Australia and his colleagues wondered whether terroir is influenced by a common alteration to DNA — the addition and removal of chemical tags called methyl groups. Such modifications, known as epigenetic changes, do not alter DNA sequence but can affect gene activity. The scientists sampled grapevines (Vitis vinifera L.) of the Shiraz cultivar from 22 vineyards in Australia’s Barossa region. They found that a vineyard’s location affected methylation levels, which in some cases varied more with location than a vine’s DNA.
The results suggest that epigenetic modifications help to explain differences between wines produced in different regions, the scientists say.