When Did Telemeres Start Limiting Somatic Cell Growth?

[Lorentz]

Telemeres are at the end of chromosomes in the somatic cells of
all (?) animals that shed a small tip at each mitosis. When the cell
runs out of telemeres, it no longer can divide. Telemeres are
implicated in senescence. On the other hand, they also prevent
widespread cancer.
It seems to me that this limit on cell growth must have been a
milestone in the evolution of metazoans. So my questions are:
1) Do all animals have telemeres?
2) Do plants have telemeres?
3) Are there telemere homologs among one-celled organisms?
4) Do bacteria have telemeres?
5) Are any microbial colonies regulated by telemere-like chunks of
DNA?
6) What type of organism was the most recent common ancestor (MRCA) to
have a telemere?

[r norman]

Are you not capable of googling "telomere evolution"?

Try
On the origin of telomeres: a glimpse at the pre-telomerase world
Jozef Nosek 1, Peter Kosa , Lubomir Tomaska
BioEssays, 28(2): 182 - 190 (2006)

http://www3.interscience.wiley.com/journal/112279242/abstract?CRETRY=1&SRETRY=0

Telomeres solve the problem of incomplete replication of linear DNA
molecules. They are not needed for circular molecules of DNA as is
found in many bacteria but they are needed for pretty much anything
with linear DNA (including some bacteria).

[Helen Hansma]

3) Tetrahymena are single-cell eukaryotes with telomeres. Key work
on telomeres was done in Tetrahymena. A Nobel Prize was awarded this
year for telomere research to Liz Blackburn, Carol Grider, and Jack
Szostak.

On Dec 31 2009, 8:57�pm, Lorentz <drosen0...@yahoo.com> wrote:
> � � Telemeres are at the end of chromosomes in the somatic cells of

[Lorentz]

On Jan 3, 6:49�pm, Helen Hansma <helen.han...@gmail.com> wrote:
> 3) �Tetrahymena are single-cell eukaryotes with telomeres. �Key work
> on telomeres was done in Tetrahymena. �A Nobel Prize was awarded this
> year for telomere research to Liz Blackburn, Carol Grider, and Jack
> Szostak.

Thank you. That helped!