Genetics of Bovine Milk Composition

Genetics of Bovine Milk Composition
In the last decade, significant technical advances in molecular genetics have led to the structural and functional characterization of genomes. Sequencing has proceeded at an accelerated pace and identification of structural variation has made possible the genetic mapping of complex traits, as well as the characterization of large numbers of expressed sequences in various tissues. The challenge ahead is how we will make use of these resources to improve animal performance and the quality of products they produce. Most variation between animals in metabolism, physiology and composition of their products is due to the quantitative segregation of multiple genes with small effects (QTL), whose _expression is conditioned by the environment. In the case of milk, a unique food capable of delivering not only nutrition but also optimal health to humans, understanding the genetic and environmental factors that cause variation are of fundamental interest in functional genomics.  Among the new applications of genetic discoveries, DNA-based tests are being used to classify animals that produce certain kinds of products or that are resistant to disease.  This information can be used for applications in marker assisted selection programs or to segregate animals that produce a certain type or quality of products.  Genomes and their analysis will also provide direct insight into understanding the biological system.  Crucial for this step is the development of properly annotated gene and protein indices, and an understanding of how cellular components interact with each other and with the environment.