Chapter 10 - Genomic selection: a molecular tool for genetic improvement in livestock

Abstract

Genetics defines the science of heredity, which deals with physical and chemical properties of the hereditary material, its transmission from one generation to the next generation, and how the content of information is expressed in building different stages of the life cycle of an individual. The genetic makeup of animals, which controls their structural configuration and productive abilities through single, as well as multiple genes present on different loci. Genes are composed of a series of nucleotide sequences arranged in chromosomes present in the nucleus. Milk production is largely affected by a combination of factors viz., genetic architecture through improved breeds selected for milk production, a favorable nutritional environment, and better managerial practices. Consequently, the genetic makeup of dairy animals plays a pivotal role in the variation of milk yield and composition. Milk production is, therefore, a factor of expression of genetic makeup and genotype-environment interactions. Hence, it is obvious to balance selection for both production (e.g., milk yield and composition) and functional (e.g., fertility, disease resistance, feed intake, and body weight) traits. High throughput techniques available in molecular genetics, in conjunction with conventional animal breeding tools, could be used to optimize animal breeding programs, resulting in higher yields through greater genetic progress enabling to determine the potential of an animal, even before the trait is expressed phenotypically. The complex interactive association among type, production and fertility traits brings attention the combination of GWAS and network analysis along with the phenotypic database to provide novel insights into the functional biology of dairy cows and the possible connections between fertility and production, justifying the further development of novel and interdisciplinary approaches toward comprehensive systematic genetic improvement.