ACKNOWLEDGEMENTS

Our ability to modify whole animal genetics has grown considerably in the last two decades. We have seen concerns regarding food safety and protection of breeding rights of genetically modified animals compel redirection of genetic engineering experimentation toward biomedical applications. Indeed, it has been nearly twenty years since the first transgenic livestock appeared in the literature, yet at this time, there are no commercially viable agricultural species. In contrast to commercialization concerns, in a variety of existing transgenic animal models, basic research into the regulation and function of specific genes (including both gain-of-function and ablation of potentially deleterious gene products) has persevered. Pioneering efforts in transgenic animal technology have markedly influenced our appreciation of the factors that govern gene regulation and expression, and have contributed significantly to our understanding of the biology of mammalian development. KEY WORDS Transgenic animals, genetic engineering, nuclear genome, mitochondrial genom