THE FOOD SAFETY OF TRANSGENIC ANIMALS - IMPLICATIONS FROM TRADITIONALBREEDING

The genetic events associated with traditional selection have implicat ions for the food safety of transgenic animals. Selection has been emp irical, relying on the use of the best animals for breeding. Molecular techniques are now being used to identify the genes selected and to d escribe the differences between alleles that are important in selectio n to improve quantitative traits. The results of such analyses provide background details of the genetic and physiological effects of the tr aditional selection of animal lines. Examples of the kinds of genes th at may be subject to selection are those coding for peptide hormones, steroid metabolic enzymes, the calcium-channel gating protein, and gen es of the major histocompatibility complex. Unselected genes, sometime s with undesirable alleles, may be carried along as ''hitchhikers'' if they are closely linked to the selected gene. In spite of this potent ial for physiologically dangerous genetic changes in selected animals, hereditary food toxicity has never been associated with a selected li ne of the common food animals. This is probably because the allowable physiological range of results of selection is limited by the requirem ent for healthy, productive animals. Based on these limitations, foods from healthy transgenic animals produced for the purpose of herd impr ovement are likely to be as safe as the foods from the untransformed p arental line. Animals are important indicators of their own food safet y.