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Caltech Researchers Find Longevity-Linked Mutation
CBNobi writes "A study headed by researchers at CalTech have found a genetic mutation occuring in mitochondrial DNA that may signify longevity. The researchers found that the particular mutation occurred in 17% of centenarians, but only 3.7% of younger individuals. They also found the mutations in identical twins, which is a possible sign of inheritance. Researchers believe the mutation controls factors in DNA replication. The report information is available in a press release by CalTech, and the research abstract is also available."
thanks, interesting article. Thoroughly outside my expertise, so I limited myself to just the press release. I hope some more knowledgable folks chime in here on it with some more user friendly opinions. It's funny, but since I was a kid I had this weird notion that just going on odds, that there had to be a very, very small percentage of the population that lived even longer than what is considered "normal" advanced age, like this reference to centennarians. And that they probably had to dodge the issue-deal with it on a practical basis, security, etc- once it became apparent they were quite "different". I know it's a subject that has been explored in various fictional literature, just wondered "what if"? This research shows there might be something to it, and it really is limited to what could be considered the second tier examples, IF there are the small populations of VERY old people as I always suspected.
While interesting, the possible applications are hyped in the press release. Although the mutation supposedly shifts the region controlling DNA replication, the study can't tell us what effect this has on the study subjects. Since the mutant mitochondrial DNA seems to increase with time in individuals living longer it may be the mitochondria with affected DNA reproduce faster than those without it. This is the same thing that happens when a cell turns cancerous, only and order of magnitude greater: unregulated division and cell immortality, at least until it outgrows its blood supply or the immune system destroys it.
The problem is, mitochondrial DNA encodes only for mitochondria (you know, those little organelles that produce ATP within the cell), not the somatic genes--that happens elsewhere, in the cell's nucleus. So while mutant mitochondria may work harder, be more efficient or otherwise make the cell's job easier, that doesn't mean this is the fountain of youth. As people age and genetic material is damaged by time and toxins mutations increase in frequency (which is why age generally = increased cancer risk), so it shouldn't be surprising that a mutation would be more common in the elderly. And predisposition to a particular mutation can be inherited (hence the twin concordance mentioned in the study).
I would be interested in what the percentage of mutant mtDNA is other ethnic groups, or among families where longevity is documented among several family members. And the figure of 17% really isn't that striking for a genetic marker that really may be playing a role in selection, at least to my statistically-challenged mind.
--thanks. I find the most interesting aspect is that it increased over time, wasn't a constant. To me it now seems like an immune response based on increasing needs, following your explanation, if there were a way to correlate what the cumulative total of damaging factors represented quantitatively. Well, if I'm understanding this adequately.
Actually, if you look for the research of Wolford, you'll find that his theory is that underclocking the body's metabolism by limiting caloric intake is critically important to increasing life span.
He's done experiments with mice and he's living his own theory, too.
Personally, I find his lifestyle too difficult - I'm addicted to food.
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