Minimizing the exposure to UV light when extracting DNA from agarose gels.

It is common practice to use agarose gel electrophoresis for the purification of DNA molecules before cloning steps. To this end, the gels are stained with ethidium bromide (EtdBr) and viewed under UV light. The bands of interest are then excised from the gel, and the DNA can be extracted from the agarose by several methods (1). The main disadvantage of this method is the fact that the DNA and the experimentor are exposed to UV light for a considerable time, especially when several bands have to be excised. We describe a simple way (Table 1) to minimize the exposure to UV light, while at the same time drastically reducing the risk of DNA degradation and of cutting out the wrong bands.