The use and abuse of chromosomal aberrations as an indicator of genetic damage

There are now many systems available for obtaining quick qualitative and quantitative assessments of chromosomal aberrations induced by various agents, and a number of these are being widely used as screening methods for possible genetic hazards. Qualitative studies are valid provided that (a) observation is not confined to any one test system, and (b) care is taken to ensure that aberrations observed are not the result of the experimental methods employed. However, the direct relationship of the gross structural changes that are observable, and the production of “heritable mutation” is not necessarily as clear as is often supposed. Very many quantitative studies are open to serious objection on the grounds that little or no thought has been given either to the time and mode of action of the compound under test in relation to the cell cycle, or to the profound perturbations which mutagens produce in the cell population. Often long treatments are given, and the same single fixation time (usually some hours after treatment) used for all “doses”. In such experiments it is certain that the cellular populations are so changed by the time assessment is made that reliable estimates of aberration frequency cannot be obtained. These points are illustrated by reference to work with radiomimetic chemicals in plant cells, and some conclusions about experimental design for meaningful results drawn

Biology · Computational biology · Environmental health · Gene · Mutation · Population · Carcinogens and Genotoxicity Assessment · Computer Science · Genetically Modified Organisms Research · Genetics · Medicine · Plant Genetic and Mutation Studies