Large amounts of silica gel-preserved material are currently scattered throughout the department; DNA samples have been accumulating more and more rapidly in recent years. The molecular collections section is a very new one, charged with bringing all this material together in optimal storage conditions.
The two types of material receive very different preparation treatments:
- Silica gel-preserved material
Small samples of fresh material are air dried and stored in sealed bags with silica gel crystals. This ensures the material remains dry and well-preserved without the use of any chemicals or treatments which might damage DNA.
- DNA samples
Pieces of silica gel-preserved specimens are finely ground using an automated grinder, or sometimes by hand using a mortar and pestle. DNA is extracted using primers and amplified if necessary. These are used for DNA sequencing. Spare material is stored and can be used for further investigations.