Bacteria do not need telomerase because their chromosomes are circular and do not have ends. Bacteria don’t require telomerase because their chromosomes differ from those of eukaryotes. Bacterial chromosomes are circular, lacking the linear ends found in eukaryotic chromosomes. Consequently, they don’t face the end-replication problem that eukaryotic chromosomes do. During DNA replication, the DNA at the very end of a linear chromosome cannot be fully copied, leading to gradual shortening.
Telomerase is an enzyme that adds repeated sequences to the ends of linear chromosomes, called telomeres, to protect them from degradation and damage. Telomeres shorten with each round of DNA replication, and when they become too short, the cell may stop dividing or die. Therefore, telomerase is important for the maintenance of chromosome stability and cell longevity in eukaryotes, which have linear chromosomes4. However, bacteria do not face the same problem of chromosome end-replication, because their DNA is circular and does not have telomeres. Thus, bacteria do not require telomerase.
