In vitro selection of functional nucleic acid sequences

The power of in vitro selection methods for the isolation of nucleic acids that display a desired property derives from the enormous number of sequence variants that can be surveyed with relative ease using controlled in vitro biochemistry. This methodology has found a variety of applications, ranging from the study of nucleic acid-protein interactions and natural ribozymes to the isolation of nucleic acids with potential as diagnostic or therapeutic reagents or with new catalytic activities. The number of reported applications is growing exponentially, and each application presents new variables and challenges. The goal of this article is to guide prospective users through the myriad decisions that must be made in the design and execution of a successful in vitro selection experiment.