Telomere

Telomeres are repetitive TTAGGG DNA sequences capping the ends of linear chromosomes, protecting them from degradation, fusion, and erroneous repair. Each somatic cell division shortens telomeres because DNA polymerase cannot fully replicate chromosome ends. Critically short telomeres trigger senescence or apoptosis. Telomere attrition is one of the twelve hallmarks of aging and is associated with cardiovascular disease, immune decline, and reduced regenerative capacity.