Yang Yunzhou, Wang Huiying, Liu Yi, Zhai Shaojia, Liu Haodong, He Daqian
Institute of Animal Husbandry & Veterinary Science, Shanghai Academy of Agricultural Sciences, Shanghai, 201106, PR China.
Institute of Animal Husbandry & Veterinary Science, Shanghai Academy of Agricultural Sciences, Shanghai, 201106, PR China; College of Animal Science and Technology, Yunnan Agricultural University, Kunming, 650500, PR China.
Poult Sci. 2024 Dec;103(12):104324. doi: 10.1016/j.psj.2024.104324. Epub 2024 Sep 11.
Two basic plumage color patterns are observed in adult geese: solid grey (G) or colorless white (W). However, a Chinese indigenous breed, the Wugangtong goose (WGT), continues to be subject to selective breeding efforts as it displays segregation of plumage colors, including G, W, and a novel color pattern designated Wb (G with white breast circles). The underlying genetic mechanisms responsible for the Wb phenotype are yet to be determined. The current study employed the population differentiation index (F) to analyze 90 geese exhibiting diverse plumage colors, identifying the fifth intron of EDNRB2 as a particularly noteworthy region with the highest F values. Sanger sequencing of the region surrounding the EDNRB2 gene identified a 14-bp insertion within exon 3 as the causal mutation. The heterozygosity of this 14-bp insertion and wild-type alleles was completely associated with the Wb phenotype, thereby substantiating the codominant nature of the G and W phenotypes. An inter-species corroborated this finding cross between the graylag (no 14-bp insertion) and the swan goose (homozygous for the 14-bp insertion) breeds, as hybrids from this cross exhibited the Wb phenotype. Transcriptomes from white breast patches and gray dorsal skins of 4 Wb geese were compared. A significant downregulation of genes involved in melanin synthesis and melanocyte development was observed, including EDRNB2 and MLANA. The downregulation of MLANA indicated that the mutated EDNRB2 resulted in melanocyte loss in specific body regions, as MLANA is a marker gene for melanocytes. The findings were corroborated by melanin staining using the Mansson-Fontana method, which revealed no melanin particles deposited in the white breast patches. In summary, the gray plumage color was codominant to the white color in WGT geese, and plumage color variations were controlled by EDNRB2. The findings of our study offer valuable and practical guidance for the purification of plumage colors among WGT, whether through traditional phenotype selection or molecular breeding methods.
纯灰色（G）或无色白色（W）。然而，中国本土品种武冈铜鹅（WGT）仍在进行选择性育种，因为它表现出羽毛颜色的分离，包括G、W和一种新的颜色模式Wb（带有白色胸环的灰色）。导致Wb表型的潜在遗传机制尚未确定。当前的研究使用群体分化指数（F）分析了90只表现出不同羽毛颜色的鹅，确定EDNRB2基因的第五内含子是F值最高的特别值得关注的区域。对EDNRB2基因周围区域进行桑格测序，确定外显子3内的一个14bp插入为因果突变。这种14bp插入与野生型等位基因的杂合性与Wb表型完全相关，从而证实了G和W表型的共显性性质。灰雁（无14bp插入）和鸿雁（14bp插入纯合）品种之间的种间杂交证实了这一发现，因为该杂交的后代表现出Wb表型。比较了4只Wb鹅白色胸部斑块和灰色背部皮肤的转录组。观察到参与黑色素合成和黑素细胞发育的基因显著下调，包括EDNRB2和MLANA。MLANA的下调表明突变的EDNRB2导致特定身体区域的黑素细胞丢失，因为MLANA是黑素细胞的标记基因。使用曼森 - 丰塔纳方法进行的黑色素染色证实了这一发现，该方法显示白色胸部斑块中没有黑色素颗粒沉积。总之，在WGT鹅中，灰色羽毛颜色与白色共显性，羽毛颜色变异由EDNRB2控制。我们的研究结果为通过传统表型选择或分子育种方法纯化WGT羽毛颜色提供了有价值的实用指导。
