Objective Adenomatosis polyposis coli down-regulated 1 (APCDD1) is a conserved single-pass transmembrane protein that negatively regulates WNT signaling and is closely associated with cell proliferation and differentiation. This study aims to investigate the association between APCDD1 gene polymorphisms and body measurement and reproductive traits in goats, providing a theoretical basis for goat breeding and variety selection.

Method Body measurement, reproductive trait data, and blood samples were collected from 349 Leizhou goats and 516 Chuanzhong black goats. Genomic DNA was extracted, and PCR amplification, sequencing, and genetic analysis techniques were employed to detect polymorphic loci within the APCDD1 gene.

Result Two mutation loci, g.42518141C>G and g.42517714G>C, were identified in the exon region of the APCDD1 gene. Both loci exhibited polymorphism in both goat breeds and were significantly associated with some body measurement traits and litter size. In Leizhou goats, individuals with the CC genotype at the g.42518141C>G locus showed significantly superior performance in withers height, body length, and hip width compared to those with the GG genotype (P<0.05). Additionally, individuals with the CC and CG genotypes had significantly higher litter sizes than those with the GG genotype (P<0.01). At the g.42517714G>C locus, CC-genotype individuals exhibited better performance in body height and thigh circumference(P<0.05), and individuals with the CC and CG genotypes had significantly higher litter sizes than those with the GG genotype (P<0.05). In Chuanzhong black goats, individuals with the CC and CG genotypes at the g.42518141C>G locus showed significantly superior performance in body height and chest circumference compared to those with the GG genotype (P<0.05), and had significantly higher litter sizes (P<0.05). However, at the g.42517714G>C locus, individuals with the GG genotype had significantly higher litter sizes than those with the CC genotype (P<0.05).

Conclusion Two key polymorphic loci g.42518141C>G and g.42517714G>C of the APCDD1 gene were identified in Leizhou goats and Chuanzhong black goats in this study, which were confirmed to be significantly associated with body measurement traits and litter size in a breed-specific manner.