Utilization of Critical Periods During Development to Study the Effects of Low Levels of Environmental Agents
The identification of susceptible subpopulations serves basic as well as applied purposes. The biological properties by which a subpopulation differs from less susceptible individuals furnish important clues about the basic mechanisms by which an environmental agent impinges on biological material of all organisms (e.g., repair deficiencies shed light on repair in general); they also provide information on the pathways between the original interaction and the finally expressed endpoint. From a more applied point of view, the existence of susceptible subpopulations may lead to limitations in permissible doses of an environmental agent. Where a subpopulation cannot be physically separated from the main population, such limitations must be to the overall population. Alternatively, the susceptible subpopulation may have to be restricted from certain environments, e.g., the workplace — a procedure that can have social and legal implications.
KeywordsCritical Period Inbred Strain Axial Skeleton Oocyte Number Presacral Vertebra
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