We support Henry Nicholls' plea to unite museum exhibitions with behind-the-scenes research (Nature 484, 36; 2012). But to avoid jeopardizing the scientific worth of collections, caution is needed if that research is done in molecular-biology laboratories under the same roof.

Museums store important, often irreplaceable, biological specimens. To protect the authenticity of their DNA, contamination must be prevented. Extraneous DNA amplified in a museum lab by the polymerase chain reaction can easily be transferred to collection storage areas unless strict safeguards are in place.

Protocols similar to those used for studying ancient DNA should be applied to the development and operation of molecular-biology labs within museums. For example, the labs should be in a separate building, with a one-way flow of people and consumables from the collection area to the lab.