TOWARD ALTERING MILK-COMPOSITION BY GENETIC MANIPULATION - CURRENT STATUS AND CHALLENGES

The implementation of large-scale genome mapping and sequencing has im proved the understanding of animal genetics. A large number of gene se quences are now available to serve as regulatory elements or genes of interest. Although the central thrust of this work is focused on under standing disease states, the manipulation of normal metabolic processe s is feasible. To date, the genetic manipulation of livestock has been limited to the permanent addition of genes of clinical interest. This study explores the utility of genetically engineered cattle as a mean s of altering milk composition to improve the functional properties of milk, increasing marketability. Improvements would include increasing the concentration of valuable components in milk (e.g., casein), remo ving undesirable components (e.g., lactose), or altering composition t o resemble that of human milk as a means of improving human neonatal n utrition. The protracted time lines of genetically modifying dairy cat tle has prompted the development of animal models. A model for dwarf g oats is discussed in terms of circumventing the lengthy time lines inv olved in generating transgenic cattle and allowing for an accelerated expansion of research in molecular genetics of dairy animals. Thus, th e genetic manipulation of dairy cattle is feasible and could have sign ificant impacts on milk quality, attributes of novel dairy products, a nd human health.