Telomeres

Telomeres, repetitive DNA sequences and associated protein complexes at the ends of eukaryotic chromosomes are critical guardians of genome integrity and play an essential role in cellular longevity. These specialized structures undergo dynamic changes during cellular divisions and act as protective caps, preventing the loss of coding genetic material (due to peculiarities of the replication process) and the fusion of chromosomal ends. They also participate in cellular processes such as DNA replication, repair, and senescence. Telomere length maintenance is tightly regulated by telomerase and alternative lengthening of telomeres (ALT) mechanisms, which have been extensively investigated in physiological aging and diseases. In humans, the antagonistic phenomena of excessive telomere erosion or elongation may translate into degenerative diseases (telomeropathies) and cancer. This chapter provides a comprehensive overview of telomere biology, including their structural composition, functions, maintenance, and the intricate interplay between telomeres and cellular processes crucial for preserving genetic information.