β Scribed by Lynn Caporale
No coin nor oath required. For personal study only.
Sir, As the vertebrate immunoglobulin genes and other examples of genomic creativity demonstrate so clearly, natural selection has favored the evolution of a wide range of biochemical mechanisms that align the probability of distinct classes of genetic change with the probability that such changes might be adaptive rather than destructive.
In Darwin in the Genome, (1) I describe diverse examples of such creativity and suggest that such mechanisms are far more prevalent than we realize, such that evolution is not completely dependent upon mutations that are both rare and random.
In his review of Darwin in the Genome, (2) the Editor makes what is perhaps the clearest statement of the thesis of the book, but remains unconvinced that ''diversity-generating'' mechanisms that ''convey a selective advantage on organisms that possess them'' could evolve outside of special, ''arms race'', circumstances, i.e. spots in the genome involved in pathogen/immunity and predator/prey challenges; not only is the selective pressure from evolutionary arms races clear, but, importantly, it is possible to point to key genes where it would be advantageous for such ''diversity-generating'' mechanisms to focus; the Editor raises the essential point, that it is ''not clear how for morphological evolution . . . a population would 'know' which genes should experience accelerated mutation in order to have selective advantage for some future evolutionary path''.
In thinking through the Editor's challenge, I see the question transform from a qualitative to a quantitative one that well may inform our understanding of special challenges, other than pathogens/hosts and predators/prey, that repeatedly are confronted by a lineage of organisms.
π SIMILAR VOLUMES
on the diseases is not yet operational. Such a website would be a great help to all, but would admittedly be the cause of an enormous amount of work. Overall, this book more than meets its goals in providing a variety of answers to questions that all of us ask at one time or another about our health