A Bright Idea

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Science  29 May 2009:
Vol. 324, Issue 5931, pp. 1118-1119
DOI: 10.1126/science.324_1118d

The identification of single-nucleotide polymorphisms (SNPs) across individuals can contribute to characterizing underlying genetic variation in humans, DNA damage, and potential biomarkers of disease. However, it is currently challenging to detect SNPs in real time at room temperature and without the addition of a battalion of exogenous reagents.

Xiao et al. have engineered a detection system consisting of a single strand of DNA, which folds into a discontinuous double helix composed of three seven–base pair stems and incorporates both a fluorescent moiety and a quencher. When this molecule finds a perfectly complementary piece of DNA, it forms a detector-target hybrid, disrupting the proximity of the fluorophore and quencher, and yielding a fluorescent burst. It can discriminate between targets differing by only a single nucleotide, and hybridization to the target occurs within 30 min at room temperature and in the presence of a 64-fold excess of a singly mismatched competitor.

Angew. Chem. Int. Ed. 48, 10.1002/anie.200900369 (2009).

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