Methods and compositions for detecting polynucleotides

Methods of determining the presence or amount of a target polynucleotide in a sample are provided. A sample that contains a target polynucleotide, a nucleic acid analog that is complementary to a target nucleic acid sequence of the target polynucleotide, and a dye for which the rate of change in an optical property is different in the presence and absence of a target polynucleotide/nucleic acid analog hybrid are combined to produce a reaction mixture. The rate of change in an optical property of the dye in the reaction mixture is compared to a reference value characteristic of the rate of change in the optical property of the dye in a similar reaction mixture containing a known amount of a polynucleotide/nucleic acid analog hybrid to determine a relative rate of change in the optical property. The relative rate of change in the optical property of dye in the reaction mixture is correlated with the presence or amount of the specified target polynucleotide in the sample.