Figure 3

Schematic representation of aTL measurement by qPCR. One pair of chromosomes is shown, circles represent centromeres. Regions containing telomere repeats (TTAGGG)n are coloured blue. As shown, telomere lengths can vary between chromosomes and even between the two ends of a single chromosome. The arrows represent the primer pairs used to amplify the telomere sequences. The telomere PCR signal is a measure of telomere length, because the number of telomere primers that can bind the telomeric DNA at the beginning of the PCR is directly proportional to the total summed length of all the telomeres in the cell (adapted from [38]).