MATERIALS 10x Amplification buffer Include 0.01% (w/v) gelatin in the buffer. 10x TBE electrophoresis buffer Use TBE at a working strength of 1x (89 mM Tris-borate, 2 mM EDTA) for polyacrylamide gel electrophoresis. 6x Gel-loading buffer I Formamide loading buffer Human genomic DNA to be screened for point mutations Dissolve the DNA at 10 μg/ml in TE (pH 7.6). Oligonucleotide primers, forward and reverse (35 μM each) in TE (pH 7.6) Restriction enzymes (optional) Thermostable DNA polymerase Taq DNA polymerase is recommended. [ -32P]dCTP (3000 Ci/mmole, 10 mCi/ml) dNTP solution (PCR grade) containing all four dNTPs, each at a concentration of 1 mM (pH 7.0)