Associations of ORMDL1 gene copy number variations with growth traits in four Chinese sheep breeds

Copy number variations (CNVs) are gains and losses of genomic sequence of more than 50 bp between two individuals of a species. Also, CNV is considered to be one of the main elements affecting the phenotypic diversity and evolutionary adaptation of animals. ORMDL sphingolipid biosynthesis regulator 1 (ORMDL1) is a protein-coding gene associated with diseases and development. In our study, the polymorphism of ORMDL1 gene copy numbers in four Chinese sheep breeds (abbreviated CK, HU, STH, and LTH) was detected. In addition, we analyzed the transcriptional expression level of ORMDL1 gene in different tissues of sheep and examined the association of ORMDL1 CNV with growth traits. The statistical analysis revealed that ORMDL1 CNV was remarkably correlated with body height, heart girth, and circumference of cannon bone in HU sheep ( $$ ), and there are significant effects on body weight, body height, body length, chest depth, and height of hip cross in STH sheep ( $$ ). In conclusion, our results provide a basis for the relationship between CNV of ORMDL1 gene and sheep growth traits, suggesting that ORMDL1 CNV may be considered a promising marker for the molecular breeding of Chinese sheep.