Telomere length refers to the protective caps located at the ends of chromosomes, and it progressively shortens with each cell division.

Telomeres consist of repetitive DNA sequences that serve to safeguard the ends of chromosomes from degradation and prevent them from fusing with other chromosomes. As cells undergo division, telomeres shorten until they reach a critical threshold, which triggers either cellular senescence or apoptosis. Thus, telomere length plays a vital role in regulating cellular lifespan and maintaining genomic stability.

The enzyme telomerase is responsible for maintaining telomere length by adding telomeric repeats to the ends of chromosomes. Telomerase activity is notably high in stem cells and germ cells, which possess the capability to divide indefinitely. In contrast, telomerase activity is significantly lower in most somatic cells, resulting in the gradual shortening of telomeres and, eventually, cell death.

Shortened telomeres have been linked to aging, age-related diseases, and cancer. Dysfunction in telomeres can lead to chromosomal abnormalities, activate DNA damage responses, and induce cellular senescence, all of which contribute to the progression of cancer and other diseases.

Therefore, understanding telomere length and its regulatory mechanisms is crucial for comprehending cellular processes related to aging, disease, and cancer. Advances in telomere biology have paved the way for the development of telomerase-targeted therapies for cancer and potential interventions aimed at age-related diseases.