Genetic association of wool quality characteristics in United States Rambouillet sheep

Abstract

Introduction: Fine wool production is an important source of revenue, accounting for up to 13% of total revenue in extensively managed wool sheep production systems of the United States. The Rambouillet are a predominant breed that excels in wool quality characteristics. Understanding the genetic basis of wool quality characteristics would aid in the development of genomic breeding strategies to facilitate genetic improvement.Methods: Wool characteristics and DNA were collected for rams enrolled in the North Dakota State University and University of Wyoming annual central performance ram tests over a three-year period (2019–2021, N = 313). The relationships of wool quality characteristics including grease fleece weight adjusted 365 days (wt. 365 adj.), clean fleece wt. 365 adj., staple length 365 adj., average fiber diameter, face wool cover, amount of skin wrinkles and belly wool were evaluated through genome-wide association studies (GWAS), Pearson correlation and ANOVA.Results: The GWAS identified four genome-wide significant genetic markers (p-value <1.19e-06) and five chromosome-wide significant markers (p-value <1.13e-05) on chromosomes 1, 2, 4, 15, and 19. Significant markers were associated with genes notable for relevant wool biological functions, including the gene ABCC8 which codes for SUR1, an ATP-sensitive potassium channel known to affect hair growth and 60S ribosomal protein L17-like, previously found to be expressed during follicle formation. The strongest Pearson correlation coefficients were identified between clean fleece wt. 365 adj. and grease fleece wt. 365 adj. (r = 0.83) and between clean fleece wt. 365 adj. and staple length 365 adj. (r = 0.53). Additionally, clean fleece wt. 365 adj. was correlated with final body weight (r = 0.35) and scrotal circumference (r = 0.16). Staple length 365 adj. (p-value = 5e-04), average fiber diameter (p-value = .0053) and clean fleece wt. 365 adj. (p-value = .014) were significantly associated with belly wool score.Discussion: The results of this study provide important insight into the relationships between wool quality characteristics and report specific markers that Rambouillet sheep producers may use to help inform selection and breeding decisions for improved wool quality.

Genomic Characterization of Quality Wool Traits in Spanish Merino Sheep

“…The results of the present work show that the wool of the pure Spanish Merino continues to be among the finest, despite the fact that for decades, wool quality has not been used as a criterion for selection, with the fiber diameter equaling or surpassing that of other breeds previously studied, such as Akkraman [ 20 ], Chinese Merino [ 21 , 22 , 23 , 24 ], Crossed Merino [ 25 ], or Rambouillet [ 26 ]. However, the diameter of the fibers currently observed in Spanish Merino appears to be significantly coarser compared to those typically found in breeds highly selected for producing fine wool, such as Uruguayan sheep, which boast a remarkable fineness, with fibers measuring around 16.6 microns [ 27 ], or the Australian Merino, with an average fiber diameter below 16.5 microns [ 28 ].…”

Angular limb deformity associated with TSPAN18, NRG3 and NOVA2 in Rambouillet rams

“…Rams were sampled from NDSU in 2019 (n = 44), 2020 (n = 60), 2021 (n = 55), and from UWY in 2019 (n = 74), 2020 (n = 43) and 2021 (n = 66). The genotype data of 313 of these rams have been analyzed in previously published work 56 . DNA was isolated from blood at the University of Idaho using the phenol–chloroform method 57 and tissue samples were provided to AgResearch for DNA extraction.…”