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ARS Home » Southeast Area » Booneville, Arkansas » Dale Bumpers Small Farms Research Center » Research » Publications at this Location » Publication #397515
Research Project: Sustainable Small Farm and Organic Grass and Forage Production Systems for Livestock and Agroforestry

Location: Dale Bumpers Small Farms Research Center

Title: Inbreeding and effective population size of United States Katahdin sheep

Author
item BECKER, GABRIELLE - University Of Idaho
item Burke, Joan
item LEWIS, RON - University Of Nebraska
item MILLER, JAMES - Louisiana State University
item MORGAN, JAMES - Round Mountain Consulting
item Rosen, Benjamin - Ben
item Van Tassell, Curtis - Curt
item NOTTER, DAVID - Virginia Tech
item MURDOCH, BRENDA - University Of Idaho

Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2022
Publication Date: 2/1/2023
Citation: Becker, G., Burke, J.M., Lewis, R.M., Miller, J.E., Morgan, J.L., Rosen, B.D., Van Tassell, C.P., Notter, D.R., Murdoch, B.M. 2023. Inbreeding and effective population size of United States Katahdin sheep. World Congress of Genetics Applied in Livestock Production. https://doi.org/10.3920/978-90-8686-940-4_706.
DOI: https://doi.org/10.3920/978-90-8686-940-4_706

Interpretive Summary: Katahdin sheep are a composite hair breed reared for meat production and known for parasite resistance traits. It is important to understand heterozygosity, inbreeding and effective population size in a study population which tell us about genetic diversity, potential introduction of mistakes in genes which could affect economic traits such as growth and reproduction. Scientists from Agricultural Research Service - Booneville, AR, University of Idaho, University of Nebraska-Lincoln, and Round Mountain Katahdin, AR, genotyped a population of sheep from 23 flocks in the U.S. which represented nearly 5,000 animals to determine that mean inbreeding of Katahdin sheep was lower than that reported for other sheep breeds, mean heterozygosity was greater and effective population size was intermediate to estimates for other breeds. This information is important to sheep producers, geneticists, breeders, and scientists to understand diversity of genetics in sheep populations and make decisions about future breeding and selection.

Technical Abstract: Katahdin sheep are a composite hair breed reared for meat production and known for parasite resistance traits. The aim of this study was to calculate observed heterozygosity (HetO), inbreeding coefficients and effective population size (Ne) in a study population representing 23 U.S. flocks (N = 4,884 sheep) with 50K genotype data. In the U.S. Katahdin, mean HetO was 0.37 and mean inbreeding coefficient (Fhat2) was 0.01. Inbreeding coefficient estimates were statistically different (Kruskal-Wallis P-value < 2.2e-16) between flocks. The Ne of the study population examined was N = 172 at 13 generations ago, with average linkage disequilibrium r2 of 0.04 for the generation. Maintaining genetic diversity relies upon maximizing Ne and minimizing inbreeding within a population. The current study found that mean inbreeding of Katahdin sheep was lower than published for other sheep breeds, mean HetO was greater and Ne was intermediate to estimates for other breeds.