REPLICOMETER. “The sought-after mechanism should not be called a clock or chronometer because these are devices used for the measurement of the passage of time. Because the replicative limit of normal cells is not directly the result of the passage of time but the number of DNA replications, the putative mechanism should be more properly referred to as an event counter.”
http://protein.bio.msu.ru/biokhimiya/contents/v62/full/62111380.html