Simple SummaryThepleomorphic adenoma gene 1(PLAG1) gene has attracted a lot of attention as a gene related to myogenesis. ThePLAG1gene is a key gene for growth traits in sheep, cattle, pigs, and chickens. However, it has also become the focus of research to determine whether it is the dominant gene affecting growth traits in goats. To address this problem, a bioinformatics analysis, mRNA expression (n = 6), and identification of copy number variants (CNVs) (n = 224) ofPLAG1were conducted in Shaanbei white cashmere (SBWC) goats. The findings indicated that the gene had a large number of conserved motifs, the expression level of the gene was higher in fetal goats than in adult goats, and all CNV loci were found to be associated with goat growth traits (p< 0.05), making them effective molecular marker loci for goat breeding.AbstractThepleomorphic adenoma gene 1(PLAG1) gene, as the major gene responsible for growth, plays a vital role in myogenesis. Meanwhile, the relationship between copy number variation (CNV) of this gene and growth traits in goats remains unclear. Therefore, this study investigated four aspects: bioinformatics analysis, mRNA expression (n = 6), CNV detection (n = 224), and association analysis. The findings indicated that the gene had a large number of conserved motifs, and the gene expression level was higher in fetal goats than in adult goats. Three CNV loci were selected from the database, among which CNV1 was located in the bidirectional promoter region and was associated with goat growth traits. CNV analysis showed that CNV2 and CNV3 of thePLAG1gene were associated with growth traits such as body weight, heart girth, height at hip cross, and hip width (p< 0.05), with CNV1 loss genotype being the superior genotype, and CNV2 and CNV3 median and gain genotypes of being superior genotypes. This finding further confirms that thePLAG1gene is the dominant gene for growth traits, which will serve as theoretical guidance for goat breeding.