Telomeres consist of short DNA sequences that repeat hundreds to thousands of times. In humans, the telomere repeat sequence is TTAGGG. These sequences cap and stabilize the chromosomes, ensuring their integrity and preventing them from being mistaken as damaged DNA.

Telomeres play a vital role in cellular aging and lifespan. With each cell division, these protective caps gradually shorten due to the limitation of DNA replication processes. Eventually, telomeres become critically short, triggering cellular senescence or programmed cell death.

Telomerase is an enzyme that can extend telomeres by synthesizing and adding new telomeric DNA sequences to the ends of chromosomes. It contains an RNA template that serves as a guide for the addition of telomere repeats.

Telomerase activity is particularly high in germ cells, stem cells, and cancer cells, enabling them to maintain longer telomeres and proliferate indefinitely. In most somatic cells, however, telomerase is inactive, leading to progressive telomere shortening and eventual cell cycle arrest or apoptosis.

Telomere shortening is associated with aging, as the accumulation of DNA damage over time leads to reduced cell viability and function. It has been suggested that telomere length could serve as a biomarker for biological aging and age-related diseases.

Various factors including oxidative stress, chronic inflammation, and lifestyle choices can influence the rate of telomere attrition. Maintaining a healthy lifestyle and managing stress may help slow down telomere shortening, potentially promoting longevity and overall well-being.