Genome-Wide Association Studies For Growth And Carcass Traits In Russian Sheep

Abstract Breeding fast-growing sheep with good carcass traits is beneficial for lamb producers. However, genomic selection for relevant traits is still lagging in Russian sheep industry. In this regard, detection of the QTLs and candidate genes specific for local sheep is of great scientific and practical interest in Russia. In our research, we aimed to perform GWAS for growth and carcass traits in the QTL-mapping sheep population obtained from crossing slow- and fast-growing breeds. Backcrosses from (Katahdin× Romanov) × Romanov mapping population were genotyped with Ovine Infinium HD SNP BeadChip (Illumina, USA). Quality control in PLINK v.1.9 resulted in 459,868 SNPs which were used for GWAS. Threshold p-value for Bonferroni genome-wide significance was estimated as p = 1.09х10–7. The Manhattan plots were visualized in R package qqman. The measurements included body weight (BW), chest depth (CD), chest width (CW), and width at the iliac tubercle (WT) were recorded at the age of 6, 42 and 180 days. Significant SNPs including oar3_OAR7_44462236 (p = 8.40E-07), oar3_OAR7_44496608 (p = 8.40E-07) and oar3_OAR7_44975375 (p = 8.60E-07) were associated with WT at age of 180 days (13.31±0.23 cm). In addition, genomic regions located on chromosome 7 (44462236 – 44975375) and chromosome 2 (148067154 – 148077728) contained SNPs associated with CD at age of 180 days (21.42±0.39 cm) as well as with WT at age of 180 days. One SNPs (oar3_OAR4_4568047) on chromosome 4 and four SNPs on chromosome 7 (oar3_OAR7_44462236, oar3_OAR7_44496608, oar3_OAR7_44975375, and oar3_OAR7_45012432) were associated with BW at age of 180 days (22.61± 0.89 cm). The genes identified by GWAS were annotated. There were candidates responsible for bone metabolism, prenatal growth, skeletal muscle growth, related to meat quality and involved in carbohydrate and lipid metabolism. The reported study was funded by RFBR, project No. 17-29-08015.