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Goodbye, Dolly
goombah99 writes "Dolly, the famous cloned sheep has been put to death after being diagnosed with a progressive lung disease, according to many reports. This follows on earlier reports that she was prematurely aging, including developing arthritis. While one should be cautious about drawing conclusions from a single data point, its interesting to speculate." Here is a link to her birthplace courtesy of Captain Large Face
Although the shortening of her telomeres is well-publicized, it very well may have had nothing to do with the death. A somewhat more detailed story can be found here [Reuters].
The main suspected "kink" are the telomeres, and if we do discover it's a kink, it may be a difficult one to work around. Here's a good article on telomeres and telomerase.
Your telomere explanation was pretty good, except that telomeres aren't just any substance. They're DNA. The end of a chromosome has short repeating sequences of a few base pairs (ex: AATTAATT, etc.) which are not all replicated when a cell duplicates its genome and divides. This presumably acts as a molecular "clock" for the organism to keep track of its "age," but this is pretty controversial and unsubstantiated.
Click here to read more about telomeres. (Why don't more people link to Wiki?)
Even if this telomere function were well-established, it doesn't entirely explain the aging process. It seems that part of the process is due to oxidative damage caused by radical reactions in the mitochondria. But similar reactions happen in chloroplasts and some plants live for millenia!The exciting thing about biology is that you reach the frontiers of knowledge in the field during your first year of introductory undergraduate coursework. In math you reach the frontiers maybe by your fourth year or in grad school. For physics and chemistry, somewhere in between. Biology is full of unexplained phenomena. If you want to make a great fundamental discovery in one of the hard sciences, then become a biologist. So much is unknown!
Telomeres are repeating sequences of non-protein-coding DNA at the end of a chromosome. Due to an inefficiency involoved in the replication of chromosomes, they become shorter and shorter with each cell division. Eventually, the telomere is depleted and parts of actual genes begin to be cut off. This explains death by old age.
An interesting side note is that cancer cells do not undergo the shortening of telemeres unlike normal cells. As opposed to normal cells which have a finite lifetime, cancer cells are functionally immortal.
A little off topic, but still somewhat interesting.