Question about cell division and telomeres

[William Gaatjes]

I was sitting in the bus, reading about magnetic fields and how some researches suggest that whales can actually sense the earth magnetic field or even the magnetic field lines of rock on the ocean bottom. But this question is not about that.

I recently posted in a thread here that a cell of the human body can divide up to 40 to 60 times before something goes wrong with the telomeres. I have read that there is some enzyme that can replenish the telomeres called telomerase reverse transcriptase .
Here is my question, how does it work from going from blastocyst to trillions of cells ?
A whale for example is huge. But it cells are the same as ours. It does not have huge cells as well. So the cells of a whale must divide more often.
Just as we have to let cells divide more than for example a hamster.
How does this work ?
Anybody want to explain it ?
Is telomerase reverse transcriptase putting in over time during developmental stages ?

 

[William Gaatjes]

Do whales make more use of telomerase reverse transcriptase ?

And hamsters less ?

 

[giantpandaman2]

There's a lot more to cell division and keeping DNA mutations from cropping up than just a single enzyme. Simply put: larger organisms have more mechanisms for correcting for replication error or for signaling apoptosis in the event of catastrophic error.

Recently they deciphered part of the puzzle in elephants. http://www.slate.com/blogs/wild_thi...don_t_get_cancer_extra_tumor_suppressors.html

Whales are much more difficult to study, but it's within reason to believe it's likely they have more p53 genes as well. Further research is merited, but whales aren't the easiest subjects to gain access to.

 

[William Gaatjes]

Aha, interesting. :thumbsup:

Elephants have 38 copies of the p53 gene and we only 2.
But how does that work with the telomeres. Do elephants have longer telomeres as well ?

 

[sao123]

A comparative study of rodents concluded there was an inverse correlation between levels of telomerase expression and body size (Gorbunova & Seluanov, 2009) but no correlation between telomere length and lifespan

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3387546/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3387546/figure/F1/
http://www.jstor.org/stable/3592308?seq=1#page_scan_tab_contents