Quantification of DNA during winemaking by fluorimetry and <Emphasis Type="Italic">Vitis vinifera</Emphasis> L.-specific quantitative PCR

The ability to genotype wine would be of a great benefit to control the varietal wine authenticity. In this paper, we assessed the fate of grapevine DNA and total DNA during vinification to suggest the latest sampling point that would allow genotyping. The total DNA concentration was measured by fluorimetry and the specific Vitis vinifera L. DNA concentration was measured by quantitative PCR in samples obtained from different steps of vinifications of four wines. To elucidate the effect of pre-extraction and extraction steps on DNA yield from wine, several samples from bottle of wine, two precipitation salts, and two DNA extraction solutions were tested. It was found that hundreds of genome equivalents of grapevine DNA can be extracted from every winemaking sample and from wine. In tested samples, differences in DNA yield among wines from different grapevine varieties, differences among extraction methods, and sampling variation in wine were not statistically significant.