Xu Qiao, Luo Yabiao, Chao Zhe, Zhang Jibin, Liu Xiaolei, Tu Danqin, Guo Qin, Sun Ruiping, Wang Feng, Fang Meiying
Jiangxi Provincial Key Laboratory of Poultry Genetic Improvement, Institute of Biological Technology, Nanchang Normal University, Nanchang 330032, China.
National Engineering Laboratory for Animal Breeding, MOA Key Laboratory of Animal Genetics and Breeding, Beijing Key Laboratory for Animal Genetic Improvement, State Key Laboratory of Animal Biotech Breeding, Frontiers Science Center for Molecular Design Breeding, Department of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Animals (Basel). 2024 Dec 3;14(23):3493. doi: 10.3390/ani14233493.
Despite identifying genes regulating the coat colour in Western pig breeds, the genetic basis of the coat colour in Chinese indigenous pigs is still not understood due to the diversity of indigenous breeds and their genetic differences from exotic pigs. In this study, 215 Wuzhishan pigs with three coat colour patterns (white, black, and black-back/white-belly) were used to conduct a genome-wide association analysis. We found that genes responsible for the coat colour in the Wuzhishan breed are located on chromosome 8. Ninety-seven genome-wide significant SNPs are related to the animal's coat colour. Using a haplotype-sharing analysis, we narrowed the potential candidate region to a 10.1 Mb interval encompassing only one gene, , which participates in the regulation of melanogenesis. Two additional candidate genes, and , are located within 1 Mb of the genome-wide significant SNPs. Gene ontology analysis and literature mining suggest that these candidate genes are associated with the animal's coat colour. mRNA expression results revealed that and had significantly higher expressions in black pigs than in white pigs and higher expressions in black skin than in white skin from the same black-back/white-belly pigs. These results suggest that and are potential candidate genes regulating the coat colour in Wuzhishan pigs. Interestingly, mutations of (a gene duplication and a G to A substitution at the splicing site in intron 17) were detected in white Wuzhishan pigs but not in black-back/white-belly or black pigs, suggesting a close genetic relationship between white Wuzhishan pigs and Western white pig breeds. In summary, these results indicate that the expression of and may cause the coat colour variation by influencing the deposition of melanin, while the mutation of causes the white coat colour. Our results may provide a theoretical basis for the breeding of white coat colour Wuzhishan pigs, and shed light on the complex genetic background of coat colour variations in indigenous Chinese pig breeds.
尽管已鉴定出调控西方猪种毛色的基因，但由于中国本土猪种的多样性及其与外来猪种的遗传差异，本土猪种毛色的遗传基础仍不清楚。在本研究中，选用215头具有三种毛色模式（白色、黑色和黑背/白腹）的五指山猪进行全基因组关联分析。我们发现，五指山猪种中负责毛色的基因位于8号染色体上。97个全基因组显著单核苷酸多态性（SNP）与动物毛色相关。通过单倍型共享分析，我们将潜在候选区域缩小到一个1,010,000碱基对（Mb）的区间，该区间仅包含一个基因，其参与黑色素生成的调控。另外两个候选基因位于全基因组显著SNP的1 Mb范围内。基因本体分析和文献挖掘表明，这些候选基因与动物毛色相关。mRNA表达结果显示，在黑猪中，该基因的表达显著高于白猪，在同一黑背/白腹猪的黑色皮肤中，其表达高于白色皮肤。这些结果表明，该基因是调控五指山猪毛色的潜在候选基因。有趣的是，在白色五指山猪中检测到该基因的突变（内含子17中一个基因重复和一个剪接位点处的G到A替换），而在黑背/白腹或黑色猪中未检测到，这表明白色五指山猪与西方白猪品种之间存在密切的遗传关系。总之，这些结果表明，该基因的表达可能通过影响黑色素的沉积导致毛色变异，而该基因的突变导致白色毛色。我们的结果可能为白色五指山猪的育种提供理论基础，并为中国本土猪种毛色变异的复杂遗传背景提供线索。
