Abstract: A denaturation fingerprinting method (dnF) involves subjecting a nucleic acid segment of interest to bidirectional cycle sequencing using oppositely oriented primers and incorporating two different dideoxynucleotides (ddNTPs) in the sequencing reaction. The resulting fragments are separated by denaturing electrophoresis. In one embodiment, designated dnF2R, reactions and electrophoretic separation using the two ddNTPs are conducted separately. In an alternative embodiment, designated dnF1R, one of the ddNTPs has a mobility altering modification such that electorphoretic separation occurs when both ddNTPs are employed in the same reaction. The methods are useful for detecting genetic mutations.