TRINUCLEOTIDE REPEAT DNA STRUCTURES - DYNAMIC MUTATIONS FROM DYNAMIC DNA

Models for the disease-associated expansion of (CTG)(n).(CAG)(n), (CGG )(n).(CCG)(n), and (GAA)(n).(TTC)(n) trinucleotide repeats involve alt ernative DNA structures formed during DNA replication, repair and reco mbination. These repeat sequences are inherently flexible and can form a variety of hairpins, intramolecular triplexes, quadruplexes, and sl ipped-strand structures that may be important intermediates and result in their genetic instability.