Genome-Wide Association Study of Muscle Glycogen in Jingxing Yellow Chicken

Glucose metabolism plays an important role in many normal and pathological physiological processes in the body. The breakdown and synthesis of muscle glycogen provides ATP for muscle activities. A genome-wide association study for muscle glycogen was performed in 474 Jingxing yellow chickens to identify significant single nucleotide polymorphisms (SNPs) and insertions and deletions (INDELs) involved in muscle glycogen metabolism. A total of nine SNPs (p < 1/699341) and three INDELs (p < 1/755733) reached a significant level of potential association. The following results were obtained through a series of analyses, including additive effects and gene function annotation. Two significant SNPs were found in introns 12 and 13 of copine 4 (CPNE4) on chromosome 2. The wild-type and mutant individuals had significant differences in glycogen metabolism at two loci (p < 0.01 for both). Individuals carrying two mutations had increased muscle glycogen content. According to the gene annotation of chromosome 11, there is a significant INDEL in intron 6 of naked cuticle homolog 1 (NKD1). After the INDEL mutation, the glycogen content increased significantly. There was a significant difference between wild-type and mutant individuals (p < 0.01). These mutations likely affecting two genes (CPNE4 and NKD1) may affect glycogen storage in a pleiotropic manner. Gene annotation indicates that CPNE4 and NKD1 may affect the process of glucose metabolism. Our findings contribute to understanding the genetic regulation of muscle glycogen metabolism and provide theoretical support.