Body weight is an important trait for meat type sheep, and detecting major genes is critical for genetic improvement of this trait. This study was conducted to genome-wide association study (GWAS) of birth weight and detect possible candidate genes affecting this trait in sheep. A total of 132 Lori-Bakhatiari sheep (8 rams and 124 ewes) were selected using Case-Control method based on estimated breeding values (EBVs) for birth weight in Shooli Sheep Breeding Station in Shahrekord. The samples were genotyped using the Illumina Ovine SNP50 Bead Chip. The SNPs with GC scores < 0.6, genotype Call Rates < 95% and minor allele frequencies < 0.05 were removed from the analysis, whereas a total of 41323 SNPs and 130 sheep were remained for further analyses. In GWAS, the EBVs for birth weight were considered as the phenotypes. The Plink 1.90 beta was used for quality control and GWAS analysis. The effects of SNPs were estimated using the GCTA software. Seven significant SNPs affecting EBVs for birth weight were explored on chromosomes 1, 16, 19 and 22. A 56 kb region on the chromosome 1 contained the most significant SNPs (s54564.1 and s63115.1) which were tightly linked together. The six significant SNPs accounted for 1.2 % of total genetic variation. Four candidate genes, including RAB6B, Tf, KCNJ13 and GLGYF2 were identified on the chromosome 1. Three candidate genes including DNTT, OPALIN and TLL2 were also found on the chromosome 22. The results of this study could be used for marker assisted selection.
