Telomeres are specialized nucleoprotein structures at the ends of eukaryotic chromosomes consisting of the highly conserved non-coding sequence (T2AG3)n. Functional telomeres prevent chromosome degradation and maintain genome stability. Telomeres of a critically short length have been associated with premature ageing syndromes and reduced survival, thus indicating poor biological state. In somatic cells, telomere length declines, because base pairs are lost at each cell division owing to incomplete replication, DNA-damaging factors such as oxidative stress and changes in the telomere-associated proteins. Telomeres shorten with age within individual mammals and birds. However, such studies typically also show a high variability of telomere length within age groups. Part of this variation has a genetic basis, but such inter-individual variation in telomere length may also reflect lifestyle and associated ‘life stress’.
We measure (avian) telomeres using Pulsed Field Electrophoresis – which measures ‘Telomere Restriction Fragments’ (TRF). A notable aspect of our approach is that it excludes interstitial telomeric sequences from the measurements. These can be numerous in birds, and highly variable between individuals. The causes and consequences of variation in the number of telomeric repeats are likely to differ between terminal telomeric repeats (at chromosome ends) and interstitial telomeric repeats, and hence it may be important to be able to restrict measurements to either category.
We welcome visitors to come and measure telomeres in our lab, supervised by Ellis Mulder – feel free to contact firstname.lastname@example.org when you have an interest in measuring telomeres.
Simon Verhulst is member of the Telomere Research Network. The TRN website provides information on telomere measurement methodology, in particular qPCR as applied in epidemiological studies.