B. Regarding lab work and storage

7. Essentially, the DNA bank is a freezer that hosts extracts of DNA in an organized way. If you can´t store the samples in an ultra-low (-80ºC) freezer, you can start storing them at -20 or -40ºC ("no frost", if possible).
8. It is fundamental to choose a fast, economic and efficient method for the DNA extractions. We use the CTAB 2x (Doyle and Doyle 1987), which allows us to get enough of good quality DNA from even very little leaf material (0.01g). Only when DNAs are difficult to extract do we use commercial kits.
9. The samples in the freezer should be organized in a way that occupies the less possible space and, at the same time, allows an easy localization of the samples (boxes for 100 vials, labelling the vials and boxes,...). Also we recommend the use of screw-cap tubes to prevent leakage of the DNA solution.
10. It is desirable to cesium clean the DNAs. However, the necessary throughput is not affordable to all labs; moreover, it’s very time-consuming. Since there are alternative methods to clean DNA upon use, you can store it without cleaning, and do so when you need it for your research or for shipment.
11. Dividing the total volume of DNA extracted in aliquots of different volume is advisable in order to have multiple duplicates per sample. We have divided the samples in our DNA Bank in three different stocks: “Permanent” stock (1ml), “Working” stock (20µl) and “Exchanging” stock (40µl). Tubes with screw caps use storage space more efficiently than hinged tubes.
12. You should keep duplicates of the DNA Bank samples at different institutions maintaining a DNA bank. If this is not possible, at least keep duplicates in various freezers and in different laboratories, just in case prolonged power supply outages or other kind of negative contingencies may irreversibly affect your invaluable samples.