What factors affect nucleic acid hybridization stringency?

Hybridization stringency refers to conditions that favor formation of perfectly matched duplexes over mismatched ones. Key factors include: temperature (higher temperature increases stringency - Tm depends on GC content and length), salt concentration (lower ionic strength increases stringency by destabilizing duplexes), formamide concentration (lowers Tm, allowing stringent hybridization at lower temperatures), and probe length (longer probes are more stable). Stringency is adjusted through wash conditions in techniques like Southern blots, microarrays, and FISH. High stringency ensures specific detection, while low stringency detects related sequences.