One of the major problems in acquiring information
from archeological samples is to prevent contamination
from modern samples. As stressed under Materials
and Methods, all of the experiments were
performed with the necessary precautions to prevent
any modern contamination, in accordance with the
suggestions recently summarized by Hofreiter et al.
(2001). We also carried out three independent extractions
and two independent sets of PCR amplifications
with the appropriate negative and positive
controls. Based on the reproducibility and consistency
of the results, we believe that contamination
with modern yeast can be ruled out.