Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Replicative life span of telomerase-positive and -negative clones. Cells were counted and passaged every 5 to 7 days, and new population doublings were calculated. Cultures were considered senescent (*) if they had undergone less than one population doubling in 2 weeks.
