Compositions and methods for detecting nucleotide variants

A method of detecting a polymorphism in a test nucleic acid molecule compared to a control target nucleic acid molecule, comprising:

• (a) providing a test mixture comprising a first nucleic acid probe, a second nucleic acid probe, and the test nucleic acid molecule under conditions that permit duplex formation, wherein
• the control target nucleic acid molecule comprises a first control nucleotide sequence contiguous to a second control nucleotide sequence;
• the first probe comprises a hybridization portion complementary to the first control nucleotide sequence, and a nucleation portion comprising templated metal nanoclusters that are fluorescent;
• and
• the second probe comprises a hybridization portion complementary to the second control nucleotide sequence, and an enhancer portion comprising a nucleotide sequence that enhances fluorescent emission from the metal nanoclusters when associated with the metal nanoclusters;
• (b) exposing the test mixture to an excitation light and measuring a wavelength of fluorescence emission from the mixture;
• and
• (c) detecting the polymorphism by detecting a difference in the wavelength of the fluorescence emission of the test mixture compared to that of a corresponding control mixture comprising the first probe, the second probe, and the control target nucleic acid molecule.