Patent ID: 7179589

Claim:
A method of detecting DNA variation by monitoring the formation or dissociation of a complex consisting of: (a) a single DNA strand of a double stranded DNA of at least 40 base pairs containing the locus of a variation, wherein said single DNA strand is within a monolayer of single DNA strands which are bound to a solid surface, (b) an oligonucleotide or DNA analogue probe specific for one allele of the variation and capable of hybridizing to the single strand (a) to form a DNA duplex, (c) an intercalating dye specific for the DNA duplex structure of (a) plus (b) which forms a complex with the duplex and reacts uniquely when interacting within the DNA duplex, which method comprises: (1) steadily and progressively adjusting temperature at a rate of between 0.01 to 1° C. per second, (2) continually measuring an output signal indicative of interaction of the dye with duplex formed from the strand (a) and probe (b), and (3) recording the temperature at which a change in reaction output signal occurs which is attributable to formation or dissociation of the complex and is thereby correlated with the strength with which the probe (b) has hybridized to the single strand (a).