Genome-Wide Association Study Identifies Candidate Genes for Body Size Traits in Wanyue Black Pigs

This study aimed to elucidate the genetic basis of body-size-related traits in Wanyue Black pigs, including body length, chest circumference, forearm circumference, and hip circumference. Phenotypic data were collected from 139 four-month-old female pigs, and genotyping was performed using a 50K SNP array. After stringent quality control and genotype imputation, approximately 4,697,453 high-quality autosomal variants were retained for subsequent genome-wide association study (GWAS), transcriptome-wide association study (TWAS), and phenome-wide association study (PheWAS). The GWAS identified four genome-wide significant loci, including rs343276492 and rs321308815. TWAS results revealed that the expression level of PTH2R was significantly associated with pituitary-related traits. In addition, selection signal analysis identified multiple genomic regions related to growth, development, and environmental adaptability, which were significantly enriched in pathways such as circadian rhythm regulation and the MAPK signaling pathway. These pathways play critical roles in growth regulation and adaptive evolution in Wanyue Black pigs. Collectively, this study provides valuable candidate genes and potential molecular markers for the genetic improvement and breeding of Wanyue Black pigs.