Prehybridization/Hybridization for Hybridization in Formamide Buffers

After a thorough mixing, filter the solution through a 0.45-μm disposable cellulose acetate membrane (Schleicher & Schuell Uniflow syringe membrane or equivalent). To decrease background when hybridizing under conditions of reduced stringency (e.g., 20-30% formamide), it is important to use formamide that is as pure as possible.