All animals originally contain DNA so except for preparations where the DNA has been destroyed or for fossils which don’t usually contain DNA, then DNA is often part of type specimens. Directly extracted DNA from an animal (i.e. not amplified) might theoretically be a type since as it is part of an animal (Article 72.5.1), however it is usually present in such small quantities that to study it further requires amplification, using a copying process such as the polymerase chain reaction (PCR) before sequencing. The copied DNA cannot be a type since it is not part of an animal nor does it fit any of the other categories of things that can be types. If the copied DNA is sequenced, a sequence can be regarded as a description of the DNA originally in the animal, so the type can be the specimen or part of the specimen, e.g. a tissue sample, or pre-amplification DNA sample, on which the sequence is based (Article 72.5.6). Consequently new species can be described on the basis of DNA sequences, and while not mandatory, it is strongly recommended that the type specimen(s) from which the DNA was sequenced is preserved and deposited in a museum with a type label and data linking it to the sequence (for example a GenBank number).