Stochastic Simulation of the Kinetics of Multiple Interacting Nucleic Acid Strands

Author: Schaeffer, Joseph Malcolm

Year: 2013

Degree: Dissertation (Ph.D.)

Advisor: Winfree, Erik

Committee Members: Winfree, Erik; Pierce, Niles A.; Umans, Christopher M.; Barr, Alan H.; Bruck, Jehoshua

Option: Computer Science

DOI: 10.7907/JEBY-6X69

Abstract

DNA nanotechnology is an emerging field which utilizes the unique structural properties of nucleic acids in order to build nanoscale devices, such as logic gates, motors, walkers, and algorithmic structures. Predicting the structure and interactions of a DNA device requires good modeling of both the thermodynamics and the kinetics of the DNA strands within the system. The kinetics of a set of DNA strands can be modeled as a continuous time Markov process through the state space of all secondary structures. The primary means of exploring the kinetics of a DNA system is by simulating trajectories through the state space and aggregating data over many such trajectories.

We expand on previous work by extending the thermodynamics and kinetics models to handle multiple strands in a fixed volume, and show that the new models are consistent with previous models. We developed data structures and algorithms that allow us to take advantage of local properties of secondary structure, improving the efficiency of the simulator so that we can handle larger systems. The new kinetic parameters in our model were calibrated by analyzing simulator results on experimental systems that measure basic kinetic rates of various processes. Finally, we apply the new simulator to explore a case study on toehold-mediated four-way branch migration.

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