Significant variants and Manhattan plots for -log(10) <i>P</i>-values of variant effects for additive-genetic effects and for dominance effects for the traits tail length (TL), tail circumference (TC), body weight (BW), bedy length (BL), number of vertebrae (nVERT), fracture (FRC), axis deviation (AXISD), block vertebrae (BLCKV), wedged vertebrae (WDGV)

The aim of the present study was an in-depth genomic analysis for tail length (TL), tail characteristics, tail abnormalities and body measurements in the Merinoland sheep breed considering whole-genome sequence (WGS) data. Genomic analyses included the estimation of genetic parameters and dominance effects, genome-wide associations for the additive and dominance component, and the annotation of potential candidate genes. In this regard, we implemented a unified selection and mating experiment to create extreme lamb groups based on breeding values for TL. The 254 lambs from the selection and mating experiment were phenotyped at birth for TL, tail circumference (TC) and body length (BL) (all in cm), for body weight (BW), and X-rayed to count the number of vertebrae (nVERT) and to identify tail abnormalities for tail fractures (FRC), axis deviations (AXISD), block vertebrae (BLCKV) and wedged vertebrae (WDGV). Heritabilities from single-trait animal models using the variant-based relationship matrix were quite large for the morphological measurements TL (0.85), BL (0.93) and BW (0.85), moderate for TC (0.21) and nVERT (0.29), but close to zero for all tail abnormalities. Dominance variance for TL from the same model explained 14.95 % of the phenotypic variation, but was close to zero for the remaining traits. Breeding value correlations were negative between TL with BLCKV and WDGV, indicating a larger prevalence for tail abnormalities when breeding on short tails. Genome wide associations for additive-genetic and dominance effects for all variants were estimated with linear mixed models and generalized least squares applications. 726 significant variants were located in exons and introns of potential candidate genes with known functions on morphological trait developments, skeletal growth, and development of bone structures or vertebrae characteristics.