Thesis #42 – As a pattern of age-dependent adaptation, aging and the post-aging period are best studied using the range of methods used to study adaptation by evolutionary biologists, such as the comparative method, experimental evolution, and genomics.
By this point, you are either open to the idea that aging is only a pattern of age-dependent adaptation or you are going to return to reading articles about free radicals and telomeres, putting the distractions of Hamilton, Charlesworth, and Rose aside. Creationists can comfort themselves by reverting to Bible study, after all, shutting their minds off from the babble of scientists.
So, if you fall into the former group, what is the way forward for research on aging? What, practically speaking, should biologists interested in aging do with themselves, and their laboratory research?
They have to get re-trained as evolutionary biologists. Some of my best gerontological colleagues, such as Caleb Finch and George Martin, have in fact gone some distance down this road. They realize that they need to re-cast their research in terms of evolutionary biology.
Unfortunately, this re-casting cannot be post hoc or superficial. The problem is that the basic intellectual equipment of cell biology is profoundly deficient, from core scientific theory to the tricky articulation of the connection between useful theory and key experimentation. Cell biologists would like to find elegant pathways connecting specific molecular substrates with well-defined pathophysiologies of aging. This is what generates their attraction to free-radical and telomere theories of aging.
But they have to give up on this pattern of thought. For the underlying machinery of aging is that of evolution by natural selection, especially the ways in which it fails to sustain function. It is tricky enough to figure out how natural selection successfully sustains function. It is still harder to study how it doesn’t do so.
But this harder problem can nonetheless be approached using the tools that evolutionary biologists use to study adaptation. Among these is the comparative method. Here the beauty of the Hamiltonian theory of aging is that it makes some absolute comparative predictions, such as the absence of aging when the forces of natural selection don’t fall because of symmetrically fissile reproduction.
At the other extreme is genome-wide characterization of the genetic foundations of adaptation. This new technology is revealing the many loci that underlie both adaptation and failures of adaptation. And it is from looking at the depth and breadth of such genome-wide data that the challenge facing modern biology becomes clear: underlying any particular organismal function will be hundreds of genes which interact with each other in complex networks. The notion that we are likely to discern how these networks operate using the reductionist ideas and methods of 20th Century biology is remarkably hubristic. It reminds me of the attempts that the Taoists made to work out the foundations of human health, particularly during the first millennium CE. Despite their great ingenuity, the Taoists were much too far from having adequate conceptual or laboratory resources for the task.