DNA sequences from multiple amplifications reveal artifacts induced by cytosine deamination in ancient DNA

摘要: We show that DNA molecules amplified by PCR from extracted animal bones and teeth vary in age between 25 000 over 50 years carry C→T G→A substitutions. These substitutions can reach high proportions among the are due to occurrence of modified deoxycytidine residues template DNA. If is treated with uracil N-glycosylase, these dramatically reduced. They thus likely result deamination residues. In addition, ‘jumping PCR’, i.e. switching during PCR, may contribute When sequences ancient extracts where few initiate precautions such as sequence determination multiple clones derived more than one independent amplification necessary order reduce risk incorrect sequences. precautionary measures taken, errors induced damage unlikely be frequent ∼0.1% even under scenario each starts a single molecule.