In his pleasantly provocative opinion paper, Aubrey de Grey's argues that (a) independent age-related deteriorative processes evolve to reach approximately equal importance for the aging process as a whole, but (b) this equality can be broken by "protagonistic pleiotropies", i.e. when a process is contributing to more than one competing death causes. In particular, the fact that nDNA mutations are extremely efficient in killing by inducing cancer implies that these mutations should be irrelevant for non-cancer aging. In my opinion, (a) independent processes may not necessarily attain equal importance because of different inherent susceptibility of the corresponding genes or gene networks to evolutionary change. However, once this is taken in consideration, a refined evolutionary argument does imply that in protected environment, continuing lifespan extension will eventually make any age-progressive degenerative process a significant contributor to aging and (b) protagonistic pleiotropies may be ineffective in making degenerative processes irrelevant for aging if multiple protective pathways are available to neutralize them. (C) 2007 Elsevier Ireland Ltd. All rights reserved.
