For gels at most 1% agarose, about 0.7cm thick

• Depurination:

-soak gels in 0.25N HCl for 20 minutes with gentle shaking (4.1ml HCl in 200ml water)

-the bromophenol blue dye should turn green with HCl treatment

• Denatureation:

-soak gel in 0.5N NaOH / 1.5M NaCl for 30 to 45 min, shaking (10ml 10N NaOH, 17g NaCl)

-the bromophenol blue should once again turn blue

• Neutralization:

-soak gel in 1M Tris pH 7.5 / 1.5M NaCl for 30 to 45 minutes

• Assemble in PosiBlot apparatus as in Stratagene's instructions

• Blot for 30 to 60 minutes at 75mm Hg pressure

• UV crosslink the DNA onto membrane using Stratalinker on AutoCrosslink setting