Nucleic acid analogues are used in molecular biology for several purposes:
* Investigation of possible scenarios of the origin of life: By testing different analogs, researchers try to answer the question of whether life's use of DNA and RNA was selected over time due to its advantages, or if they were chosen by arbitrary chance;
* As a tool to detect particular sequences: XNA can be used to tag and identify a wide range of DNA and RNA components with high specificity and accuracy;
* As an enzyme acting on DNA, RNA and XNA substrates - XNA has been shown to have the ability to cleave and ligate DNA, RNA and other XNA molecules similar to the actions of RNA ribozymes;
* As a tool with resistance to RNA hydrolysis;
* Investigation of the mechanisms used by enzyme; and
* Investigation of the structural features of nucleic acids.