Polymorphism of NCAPG gene and its association with growth traits in Nanjiang Yellow goat.

The growth of livestock is influenced by both genetic and environmental factors, with genes like Non-SMC Condensin I complex subunit G (NCAPG) playing key roles in regulating growth. Previous studies have suggested that NCAPG is associated with growth traits in species such as cattle, sheep, and chickens. In this study, we comprehensively assessed NCAPG polymorphisms and their association with body weight (BW), chest circumference (CC), body height (BH), and body length (BL) at six stages (from newborn to 30 months) in 469 Nanjiang Yellow goats, utilizing the Generalized Linear Mixed Models (GLMM). Pearson correlation analysis revealed the strongest correlation between BW and CC (R = 0.91), followed by BW and BL (R = 0.87), and BW and BH (R = 0.89). Additionally, 24 single nucleotide polymorphisms (SNPs) within the NCAPG gene were identified, which were relatively conserved across closely related species. A notable missense mutation (g.5705 A > G) in exon 6 resulted in an amino acid substitution (281 Ile > Met), which may alter the physicochemical properties and conformation of the NCAPG protein. The resulting impairment in condensin function delays chromosome segregation, prolongs metaphase in growth plate stem cells, and enhances proliferative signaling, ultimately leading to variations in body size. Correlation analysis revealed that 13 of these SNPs were concurrently associated with multiple growth traits, including BH, BL, and CC. These polymorphisms in the NCAPG gene represent potential candidates for marker-assisted selection (MAS) to improve body size in Nanjiang Yellow goats.