Oliver Bogler writes:
>I agree witht the first point - bacteria, for example, do not age as there
>*must* be an unbroken chain of cells from the beginning of the bacterial
>life to today. The germline of higher organisms can be seen similarly as
>an "immortal" clone. (Immortal is in quotes because there was a heated
>debate in this group about the appropriateness of using that word to talk
>about cells - it is used purely in its narrow biological sense).
I believe a distinction must be made between the immortality of bacterial
colonies and cell lines and the immortality of the _individual_ organism.
Colonies may appear immortal and appear to have a single genotype, but the
actual, single bacterium (if it could be isolated) might be found to die after a
limited number of divisions.
In yeast, careful separation of mother and daughter cells has shown that the
mother cell stops dividing after budding and eventually dies.
Arnold Seto
seto at mit.edu
