Detection of DNA Microsatellites Using Multiplex Polymerase Chain Reaction Aboard the International Space Station

As human exploration extends further into deep space, it is critical to understand the cellular impacts of spaceflight in order to ensure the safety of future astronauts. Extended exposure to cosmic radiation and microgravity has been shown to cause genetic damage and impair cellular DNA repair mechanisms, which together can lead to genomic instability. In particular, microsatellite instability (MSI), in which dysfunction in DNA mismatch repair (MMR) causes alterations in tandemly repeated “microsatellite” sequences, is a manifestation of genomic instability that has been associated with certain cancers. In this study, we establish the feasibility of an on-orbit multiplex polymerase chain reaction (PCR)-based assay to detect mutations in cancer-related microsatellites. Multiplex PCR was used to amplify five quasimonomorphic microsatellites in space and on Earth from both wild-type and MMR-deficient human cell lines. These data provide proof of concept of simultaneous amplification of multiple DNA sequences in space, expanding in-flight research and health-monitoring capabilities.