How to measure telomere length?

Telomere length can be measured through several laboratory techniques. The most common methods include quantitative PCR (qPCR), Southern blotting, and fluorescence in situ hybridization (FISH). qPCR quantifies the amount of telomeric DNA in a sample relative to a reference gene, giving a measure of average telomere length. Southern blotting involves the separation of DNA fragments by size and hybridizing them with probes to detect telomere repeats. FISH uses fluorescent probes to visualize telomeres in individual cells, providing a direct measure of their length. These methods vary in their precision and sensitivity, depending on the purpose of the measurement.