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It's my understanding that certain turtles don't exhibit telomere shortening, and are effectively 'immortal' as well in that they don't age.
by steveitis 17y ago
It's my understanding that certain turtles don't exhibit telomere shortening, and are effectively 'immortal' as well in that they don't age.
- zackattack 17y agoDo they not get cancer?
- steveitis 17y agoI believe that they do,and at very high rates but they get run over by cars much more frequently. I think that neither really makes them less 'immortal' in the sense that this article means. Though I can see the argument that errors in cell replication leading to cancerous growths could be counted as a form of natural life span limitation, I would be surprised if it didn't also happen to this jellyfish.
- Groxx 17y agoThere's still background radiation. That the telomere doesn't shorten basically means the DNA doesn't "age"; cells don't become more likely to mutate after X duplications begin to damage the code, like ours do.
- zackattack 17y agoIs telomere shortening the sole cause of DNA replication errors? (Besides radiation, which damages the DNA directly?)
- a-priori 17y agoNo, it's not. DNA transcription errors occur all the time in our bodies, but there are elaborate repair mechanisms in the DNA that either correct it or, if its uncorrectable, kill off the cell. But, sometimes these mechanisms fail and a cell survives with mutated DNA. If the right genes are mutated, then it grows uncontrolled and you've got cancer. In order to get immortality, these repair mechanisms would have to be as robust after 1000 years as they are after 20 years. In humans, the repair mechanisms tend to degrade as you age, which is why, the theory goes, people are more likely to get cancer as they get older. It's not that there are more errors then, but that they're not corrected as well.