Estimates of heritability and candidate genes for primal cuts and dressing percentage in Santa Ines sheep

Primal cuts and dressing percentage are complex traits to record on a large scale, and information from molecular markers can improve the selection schemes for these traits. Thus, 490 Santa Ines lambs were genotyped for 50 K SNP chip to perform a genomic study for dressing percentage as well as shoulder, loin, rib, and leg yields. Variance components were estimated through a univariate animal model with a genomic relationship matrix. Weighted single-step association analyses were carried out to estimate the variance percentage explained by adjacent SNPs in genome windows (GW) of 1.0 Mbp. The estimates of heritability were 0.32 +/- 0.14 (carcass), 0.28 +/- 0.11 (loin), 0.41 +/- 0.13 (rib), 0.32 +/- 0.13 (shoulder), and 0.46 +/- 0.13 (leg). The number of GW explaining more than 1% of additive genetic variance (VA) and the total percentages of VA explained for dressing percentage, loin, rib, shoulder, and leg yields were, respectively, eight (12.5%), ten (19.2%), nine (20.1%), ten (18.8%), and seven (13.1%). Inside the GW, 355 protein-coding genes were found, 31 of them (FAIM, MRAS, PIK3CB, NHLH2, CASQ2, NAALADL2, ATPL1, GLIS3, TMOD1, CNTN1, LRRK2, HMGA2, MSRB3, ANKS1B, IR29A, LCORL, NCAPG, DTHD1, ARAP2, SYNE2, SPTB, KHDRBS3, CLVS1, NKAIN3, UBL3, SLC7A1, GSKIP, BDKRB2, SETD3, BCL11B and LRRK1) can be considered as candidate genes for carcass traits due their biological functions. Moreover, other sixteen genes take part in the neuroactive ligand-receptor interaction pathway, and this pathway was significant in functional annotation analysis of the genes mapped for primal cuts. These results revealed novel insights regarding the genetic control for primal cuts in sheep and are a novel source of information for future genomic studies related to carcass yield in livestock.