Epigenetics of Livestock Breeding
Ibeagha-Awemu, E.M.; Khatib, H., Chapter 29 - Epigenetics of Livestock Breeding. In Handbook of Epigenetics. The New Molecular and Medical Genetics (second edition), Edited by Tollefsbol, trygve o. Academic Press: 2017; pp 441-463.
Plain language summary
The animal breeding act has developed from visual assessment of desirable traits, use of complex quantitative genetic tools, animal breeding models and reproductive technologies to the genomics era and is potentially moving towards exploitation of the epigenomics phenomena. Current breeding schemes only account for part of the phenotypic variance in traits while the elusive portion could be due to other factors including epigenetics. Numerous lines of evidence have shown that epigenetic marks (DNA methylation, histone modifications, chromatin remodeling and non-coding RNA regulation) profoundly influence livestock growth and development, and phenotypic outcomes. Thus, phenotypic outcome is a multi-level interaction between the genome, epigenome, environmental factors as well as other non-genetic factors. This book chapter presented an overview of the historical development of the animal breeding art as well as that of livestock epigenetics. It also presented evidence of the epigenetic sources of phenotypic variation in livestock traits, the role of epigenetic marks in production and reproduction, and potential impact on livestock genetics and breeding.
A substantial challenge currently facing the food animal industry is developing strategies to secure a global food safety and supply to meet the population demands. To overcome this challenge, solutions must be devised to improve the efficiency of production of food animal products globally. Thus, new knowledge on factors impacting food production and quality such as deposition of adipose tissue in beef cattle, milk quality in dairy cattle and egg quality in chickens, etc., would be valuable to animal industries to improve production efficiency and meet consumer demands. Current breeding strategies account for only a portion of the phenotypic variance in trait while the elusive portion could be due to other factors including epigenetics. Adequate ascertainment of this elusive portion of variation will ensure continuous gains in livestock traits of economic importance. Changes in epigenetic mechanisms including DNA methylation, chromatin remodelling, histone modification and non-coding RNA regulation are known to impact human health, livestock well-being and productivity which is indication that these factors contribute to phenotypic outcome. Therefore, continued improvement of economically important traits in livestock will require detailed characterization of functional genomic and epigenomic variations which will ultimately link all manner of DNA sequence variations, epigenetic modifications/variations and their interaction with the environment, and application in livestock improvement programs.