There is one major problem that is encountered at the end of the chromosomes when DNA replication occurs. An analogy of what happens at the end of a DNA strand is that comparing it to what happens to the end of an old shoelace. Without the plastic protective coating around the end, over time, the shoelace becomes frayed.
Chromosomes slowly lose base pairs at the end of their strands during replication.
Telomeres can be found at the end of DNA strands. During replication, the ends of the strands, specifically the telomeres, comprise a buffer zone that compensates for the loss of genetic information. Problems involving DNA replication at the ends of chromosomes are managed by organisms ranging from yeast to humans. Genetic information in reproductive cells is the most important to preserve. Telomerase can usually only be found in sex cells.