Telomeres are protective caps for chromosome ends that are essential f
or genome stability. Broken chromosomes missing a telomere will not be
maintained unless the chromosome is 'healed' with the formation of a
new telomere. Chromosome healing can be a programmed event following d
evelopmentally regulated chromosome fragmentation, or it may occur spo
ntaneously when a chromosome is accidentally broken. In this article w
e discuss the consequences of telomere loss and the possible mechanism
s that the enzyme telomerase employs to form telomeres de novo on brok
en chromosome ends.