Mechanisms of DNA expansion.
Unstable transmission of repeating segments in genes is now recognized as a new class of mutations causing human disease. Genetic instability observed in disease is termed an "expansion mutation" when the mutation is an increase in the copy number of a repeated unit, commonly a di- or trinucleotide. While the expansion mutation is well characterized in disease, the mechanism by which expansion occurs is not clear. This article focuses on physical properties of expansion at repeating nucleotides that may provide clues to the mechanism. Both biochemical and genetic data indicate that DNA structure is part of the mechanism and the underlying cause for expansion.
McMurray
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Mayo Foundation and Graduate School, Department of Biochemistry and Molecular Biology, Department of Pharmacology, Molecular Neuroscience Program, 200 First Street, SW, Rochester, MN 55905, USA. mcmurray@mayo.edu
D001483:Base Sequence; D004261:DNA Replication; D005785:Gene Conversion; D030342:Genetic Diseases, Inborn / Q000235:genetics*; D006801:Humans; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D011995:Recombination, Genetic