Theoretical Importance of Measurements in Man

The approach to be advocated for initial use requires a major effort, at a considerable expense. It may be justified on both theoretical and practical grounds. Most of the contributions to these volumes have assumed that for the test organism under consideration there are satisfactory methods for evaluating spontaneous rates of mutation these have concentrated on how to detect significant increases above the spontaneous, normal rate. For man, as is well known, our most valid estimates of mutation rates are based on the frequency of occurrence of 

Not unexpectedly, this bold speculation has aroused intense controversy. Many of the known (or probable) amino acid substitutions in enzymatic proteins are accompanied by quantitative alterations in the activity of the enzyme (review in Harris, 1971). While the alternative enzyme states thus far studied for the most part represent genetic polymorphisms, and so could be a selected group, if Kimura is correct and the present data are representative, this suggests a looseness in the organization of biological systems, an amount of noise in nature, which is quite inconsistent with the predominantly deterministic formulation of this century. Its implications for our view of biological man are far-reaching. 

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