Little Evidence for the Preservation of a Single-Copy Gene in Charred Archaeological Wheat

We investigated 31 samples of charred archaeological cereal grains from the Northern Alpine region, dating from Neolithic to medieval times. One hundred and twenty five DNA extracts from 23 extraction series were screened for the presence of authentic DNA by PCR amplification of a 240 bp fragment from the high molecular weight glutenin subunit gene promoter (HGP) region. Criteria of authenticity adjusted to the features of charred cereal remains were applied. No PCR products were amplified in most extracts. Extraction series with positive results were further analysed with additional primer sets directed at the single-copy HGP region and with primers for the ribosomal (ITS2) or the chloroplast ( rbcL ) DNA. Most positive results of the HGP regions were subsequently considered not authentic, mainly because of molecular inconsistency. In four extracts the successful amplification of the rbcL region, the ITS2 region, or the HGP and the ITS2 region suggested the presence of authentic DNA but further and indep...