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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Genomics and Improvement Laboratory » Research » Publications at this Location » Publication #369824
Research Project: Improving Dairy Animals by Increasing Accuracy of Genomic Prediction, Evaluating New Traits, and Redefining Selection Goals

Location: Animal Genomics and Improvement Laboratory

Title: Symposium review: Exploiting homozygosity in the era of genomics-- Selection, inbreeding, and genomic mating programs

Author
item MALTECCA, CHRISTIAN - North Carolina State University
item TIEZZI, FRANCESCO - North Carolina State University
item Cole, John
item BAES, CHRISTINE - University Of Guelph

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2020
Publication Date: 6/1/2020
Citation: Maltecca, C., Tiezzi, F., Cole, J.B., Baes, C. 2020. Symposium review: Exploiting homozygosity in the era of genomics-- Selection, inbreeding, and genomic mating programs. Journal of Dairy Science. 103(6):5302-5313. https://doi.org/10.3168/jds.2019-17846.
DOI: https://doi.org/10.3168/jds.2019-17846

Interpretive Summary: The advent of genomic selection paved the way for an unprecedented acceleration in genetic progress. The increased ability to select superior individuals has been coupled with a drastic reduction in the generation interval for most dairy populations. This represents both an opportunity and a challenge. Homozygosity is now rapidly accumulating dairy populations. Currently, inbreeding depression is managed mostly through culling at the farm level and by controlling the overall accumulation of homozygosity at the population level. A better understanding of how homozygosity and genomic load are related will ensure continued genetic improvement while curtailing the accumulation of harmful recessives and maintain enough genetic variability to ensure the possibility of selection in the face of changing environmental conditions.

Technical Abstract: The advent of genomic selection paved the way for an unprecedented acceleration in genetic progress. The increased ability to select superior individuals has been coupled with a drastic reduction in the generation interval for most dairy populations. This represents both an opportunity and a challenge. Homozygosity is now rapidly accumulating in dairy populations. Currently, inbreeding depression is managed mostly through culling at the farm level and by controlling the overall accumulation of homozygosity at the population level. A better understanding of how homozygosity and genomic load are related will guarantee continued genetic improvement while curtailing the accumulation of harmful recessives and maintain enough genetic variability to ensure the possibility of selection in the face of changing environmental conditions. In this paper we present a snapshot of the current dairy selection structure as it relates to response to selection and accumulation of homozygosity, briefly outline the main approaches currently used to manage inbreeding and overall variability, and present some approaches that can be used in the short term to control accumulation of harmful recessives while maintaining sustained selection pressure.