Comparison of two DNA extraction methods in a Spanish Bronze Age burial cave

The site from La Cova des Pas, located in Menorca, is a funerary cave with a collective burial dating from the Late Bronze Age. This cave presents a good conservation of the remains of both humans and other organic elements. In spite of the good preservation, the first DNA amplification tests showed a low amplification success rate, probably owing to the presence of substances from the process of decomposition of the bodies and substances of the soil present in the samples. To overcome this problem, 41 samples were processed by means of two different extraction methods, following sterility criteria used in ancient DNA research. Two fragments of different sizes of mitochondrial DNA were amplified in order to evaluate the success rate of both methods. The results did not show a statistically significant better recovery of DNA from either teeth or bones. For the length of the retrieved DNA, the recovery was significantly better with the QIAamp kit procedure than with the phenol–chloroform method.