Better Commentary on Mitochondria, Evolution and Longevity
I briefly noted a recent paper on evolution, mitochondrial biochemistry and longevity at the Longevity Meme a little while ago. I suggested, rather tersely, the possibility that longevity was not in fact directly selected, but rather was a pleasant side effect of other evolutionary pressures on mammalian biochemistry. The commentary at Ouroboros is of a much higher quality, needless to say:
The point toward which I am laboring is this: If we are to use correlative studies as a guide to instruct future mechanistic studies, it's best to know which variables are the strongest correlates of one another, and which are merely piggybacking. In this case, since maximum lifespan is concealed from selection in the wild, one might lean toward a model in which mitochondrial proteins co-evolved with the metabolic demands of body size, with lifespan changes as a spandrel - in contrast to the author's model, in which lifespan is the driving force of mitochondrial evolution.These objections fall short of pistols-at-noon disagreement with either the model, prediction or conclusions of this paper, and I raise them to provoke discussion rather than to criticize the work before us. The paper is a step toward addressing a major issue at the interface of evolutionary and oxidative theories of aging, and it is left to the field as a whole to evaluate its conclusions and decide where to place the next foot.
A number of starting points for a comparatively gentle introduction to evolutionary theories of aging and longevity can be found back in the Fight Aging! archives. You might begin with these:
- Ageless Animals, Absent Immortality, Evolutionary Biology and Aging
- Mitochondrial Optimization and the Evolution of Human Longevity
- Discussing the Evolutionary Theory of Aging
- Evolution, Longevity and the Grandmother Hypothesis
Technorati tags: aging, biotechnology, evolution, science
Thanks for the good article. I don't believe that longevity is invisable in the wild. A new study of North American horses pre-european influence, suggests that horses with longer teeth lasted the longest, since more silica in the diet wore off the shorter length teeth sooner. The age variation of short toothed horses was 5 or 6 years; whereas horses with long teeth lasted 10 years. It led to extinction earlier for the short length horses. If you look at Amazonian parrots, it seems to play a role in sustainability of populations, even through extreme drought and other southern latitude excursions. I believe that longevity is a driver of the mitocondrial conservation of function with age. In other species longevity is divorced from species health because of local overpopulations of individual species.