This is a discussion from xprizenews.org forum which I thought would be of value to Immnst readers
- Prometheus
I wouldn't use the word "switch," because it suggests the discrete activation of a "program" of some sort. I think aging to be a continuous process of buildup of molecular lesions which eventually impair function enough to cause impaired function and pathology.
I completely agree with you on the process but have always been troubled by why it is that we do not observe molecular lesions and their effects before organisms reach a certain age (an effect exaggerated in certain species of bamboo and salmon). Don Spanton at Imminst.org also made an interesting observation which illustrates a similarly acute age related change in humans - menopause.
I suppose that one can still reconcile these observations with a non-programmatic system of aging, even if one considers that the underlying driver of such physiological changes is reflected in changes in the regulation of gene expression. But one is compelled to ask whether stochastic processes can account for all aging or whether it is the very alterations in gene regulation that permit stochastic processes to run their senescence-inducing course. Thus it becomes increasingly difficult (for me) to rationalize the existence of stochastic-only aging when considering the dramatic range of lifespan length and predisposition to degenerative disease within a species as well as the effect of progeroid syndromes. Clearly in such cases the process of aging is not simply due to increasing numbers of molecular lesions but a downmodulated ability of the cell to repair such lesions.