8. As regards the connection between mutation rate and environmental factors, Dobzhansky claimed that “the genotype is neither unchangeable nor independent of the environment. Genotypic changes do occur in which the environment plays the role of at least a trigger mechanism [...]. Moreover, any genotype is the result of an agelong process of evolutionary development, in which the environment, through natural selection, has been a force of paramount importance. The structure of the genotype, and hence the kind of changes it is capable of producing, are in the last analysis environmentally determined. The ‘determining environment’ is, however, not the one prevailing at the moment, but rather it is the sum of the historical environments to which the organism had been exposed in its phylogeny” (1951 [1937], 21).


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