Telomere heterogeneity: taking advantage of stochastic events.

Various means employed to solve problems associated with the ends (telomeres) of linear DNA chromosomes exhibit one common feature: generation of both intra- and intercellular heterogeneity of telomeres at the level of their structural and functional states. We argue that this heterogeneity is not a simple by-product of molecular pathways mediating telomere maintenance. Instead, we propose that these mechanisms were selected because they generate heterogeneity. Similarly as noise in gene expression, stochastic events at telomeres may have an adaptive value allowing cells to sustain viable and flexible populations, with implications for fields ranging from evolutionary biology to molecular medicine.