It can loosely be described as travel that takes place at regular intervals—often in an annual cycle—that may involve many members of a species, and is rewarded only after a long journey.
So after each division, the telomeres get shorter and one of the things that may happen after a while is that pieces of the genes themselves get broken off the Chromosomes.
To prevent that event from becoming a catastrophe, first responders will join members of the public in rehearsals that involve communication, evacuation, search and rescue, and other scenarios.
While most disease-causing mutated are found in humans at a rate of one in a few thousand to one in a few million people, founder mutation can occur at much higher rates.