Comparison of telomere length measurement methods

The strengths and limitations of the major methods developed to measure telomere lengths (TLs) in cells and tissues are presented in this review. These include Q-PCR (Q uantitativeP olymeraseC hainR eaction), TRF (T erminalR estrictionF ragment) analysis, a variety of Q-FISH (Q uantitativeF luorescenceI nS ituH ybridization) methods, STELA (S ingleTE lomereL engthA nalysis) and TeSLA (Te lomereS hortestL engthA ssay). For each method, we will cover information about validation studies, including reproducibility in independent laboratories, accuracy, reliability and sensitivity for measuring not only the average but also the shortest telomeres. There is substantial evidence that it is the shortest telomeres that trigger DNA damage responses leading to replicative senescence in mammals. However, the most commonly used TL measurement methods generally provide information on average or relative TL, but it is the shortest telomeres that leads to telomere dysfunction (identified by TIF,T elomere dysfunctionI nducedF oci) and limit cell proliferation in the absence of a telomere maintenance mechanism, such as telomerase. As the length of the shortest telomeres is a key biomarker determining cell fate and the onset of senescence, a new technique (TeSLA) that provides quantitative information about all the shortest telomeres will be highlighted.This article is part of the theme issue ‘Understanding diversity in telomere dynamics’.