Things fall apart.
Although the human germline mutation rate is higher than that in any other well-studied species, the rate is not exceptional once the effective genome size and effective population size are taken into consideration. Human somatic mutation rates are substantially elevated above those in the germline, but this is also seen in other species. What is exceptional about humans is the recent detachment from the challenges of the natural environment and the ability to modify phenotypic traits in ways that mitigate the fitness effects of mutations, , precision and personalized medicine. This results in a relaxation of selection against mildly deleterious mutations, including those magnifying the mutation rate itself. The long-term consequence of such effects is an expected genetic deterioration in the baseline human condition, potentially measurable on the timescale of a few generations in westernized societies, and because the brain is a particularly large mutational target, this is of particular concern. Ultimately, the price will have to be covered by further investment in various forms of medical intervention. Resolving the uncertainties of the magnitude and timescale of these effects will require the establishment of stable, standardized, multigenerational measurement procedures for various human traits.
Summing up to this point, our current knowledge of the rate and likely effects of mutation in humans suggests a 1% or so decline in the baseline performance of physical and mental attributes in populations with the resources and inclination toward minimizing the fitness consequences of mutations with minor effects.
Thus, without any compelling counterarguments at this time, it remains difficult to escape the conclusion that numerous physical and psychological attributes are likely to slowly deteriorate in technologically advanced societies, with notable changes in average preintervention phenotypes expected on a timescale of a few generations, , 100 years, in societies where medical care is widely applied…Determining the genetic contribution to any long-term trend in phenotypic attributes will require the development and implementation of standardized measurement methods that control for historical changes in ascertainment and environmental effects. Given the massive support devoted to biomedical research, surely this is a goal worth pursuing…
…A fitness decline of a few percent on the timescale of a century is on the order of the rate of global warming, and that is part of the problem. What will it take to promote serious discourse on the slowly emerging, long-term negative consequences of policies jointly promoted by political, social, and religious factors? Should such a discussion even be pursued or should the process of accelerated genetic change simply be allowed to run its course—a slow walk down the path to what called “the great Planetary Hospital”? Unlike global environmental change, there is no obvious technological fix for the uniquely human goal of intentionally ameliorating the effects of mutation, nor is there a simple ethical imperative for doing otherwise, short of refocusing our ethical goals on future descendants. Unless some altered course is taken, as improved biomedical procedures continue to minimize the cumulative consequences of our genetic (and/or environmentally induced) afflictions, and the associated biomedical industries reap the financial rewards, this will come at a progressively increasing cost for individuals with the resources and/or desires to apply such solutions.