Kinetics of repeat propagation in the microgene polymerization reaction.

Repetitive DNA is a periodic copolymer with the intrinsic property of exponential propagation to longer repeats. Microgene polymerization reaction (MPR) is a model system in which a short nonrepetitive homo-duplex DNA evolves to multiple repetitive products during heat-cool cycles. The mechanism underlying this process involves staggered annealing of complementary DNA strands of variable lengths and polymerase-mediated filling-in of the generated overhangs. MPR is considered here as a process sharing common features with two polymerization types, chain-growth and step-growth, and significant distinctions from both types were highlighted. The involved reaction stages were formulated and a kinetic model was derived and tested experimentally. The model can quantitatively explain MPR propagation and be used as a good approximation for this phenomenon.