The procedure for the successful extraction of nucleic acids depends on the type of sample being extracted and the purpose of the extraction. Protocols for the extraction of high copy number DNA samples vary significantly from those of degraded DNA samples. This study involved the development of a DNA extraction protocol that includes a cleaning procedure designed to remove external contaminants (e.g. biological, environmental, or chemical). This protocol, used to test ancient human bones, was used for testing ancient and degraded DNA samples from sturgeons.
We analysed three specimens captured in the Guadalquivir River from the mid-1970s to the early 1980s (preserved at the Biological Station of Doñana in Seville [EBD], Spain), and also included one from the Ebro river (stored at the Botanical Institute of Barcelona), and one from the collections at the Department of Zoology at the Science Faculty of the University of Granada (UGP).
The sturgeon samples were processed with forensic scientific techniques. In forensic sciences, the external components of a sample must be cleaned to ensure the results are from the specimen being tested rather than the contaminants from handling the specimens or external exposure. The samples were cleaned to remove potential contaminants and subjected to an organic extraction procedure.
A cleaning procedure was selected to obtain the individual sturgeon DNA and the samples were sufficiently cleaned and the contaminants removed from the sample. This extraction ensures reliable amplification and cloning.