Cai Ganxian, Xia Tianlan, Shao Tianqi, Darwish Hesham Y A, Xu Jiansheng, Deng Xuemei, Li Junying
Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, Beijing Key Laboratory for Animal Genetic Improvement & State Key Laboratory of Animal Biotech Breeding, China Agricultural University, Beijing 100193, China.
Department of Applied Biotechnology, Molecular Biology Researches & Studies Institute, Assiut University, Assiut 71526, Egypt.
Poult Sci. 2025 May 2;104(8):105252. doi: 10.1016/j.psj.2025.105252.
The White Leghorn chicken is a renowned high-yielding egg-laying breed, frequently utilized in hybrid breeding programs for the modification of egg production traits. However, the plumage color genes carried by White Leghorns, particularly the sex-linked barring feather gene, have rarely been exploited in breeding practices. Progeny resulting from crosses with White Leghorns predominantly exhibit white plumage due to the dominant white feather gene, which epistatically masks other feather colors. In this study, White Leghorns were reciprocally crossed with Dongxiang Black-Feathered Blue-Shelled Egg Chickens (DBBC), and the F1 generation exhibited white plumage in all individuals. In the F2 generation, feather color segregated into black, mottled, and barred patterns. Analysis revealed that the segregation of the barred plumage pattern followed a Z-linked inheritance model. In previously reported polymorphisms in the CDKN2A gene associated with barred feather patterns, we identified that only SNP4 was applicable for barring gene identification in this population. We also analyzed the correlation between the barring gene genotype and the color depth phenotype of barred feathers in adult roosters. The accuracy of identifying non-deeply barred roosters as homozygous for barring gene was 98.2 %. Population testing confirmed that the barring gene originated from the White Leghorn population. When barred hens derived from White Leghorns were crossed with black-feathered roosters, the accuracy of sex identification based on the barred feather phenotype in chicks was only 89.98 %. Two primary factors contributed to the reduced accuracy. First, two types of mottled feather phenotypes displayed epistatic effects over the barred phenotype, masking it in chicks. By excluding mottled chicks, the accuracy of sex identification increased to 93.99 %. Second, the barred feather pattern inherited from White Leghorns showed considerable variation in chicks, making identification difficult. By adopting the criterion of identifying the brightest white spot located along the midline of the chick's head, the accuracy of sex identification could be further improved. This study demonstrates that the sex-linked barring feather gene can be isolated from White Leghorn chickens and utilized for sex identification at hatch. In addition, White Leghorn chickens carry a wealth of other feather color genes that are masked by the dominant epistatic white feather gene. Crossing White Leghorn chickens with colored-feathered chickens can result in the segregation of novel feather colors, offering promising prospects for breeding applications.
白来航鸡是著名的高产蛋鸡品种，常用于杂交育种项目以改良产蛋性状。然而，白来航鸡携带的羽色基因，尤其是伴性横斑羽基因，在育种实践中很少被利用。与白来航鸡杂交产生的后代由于显性白羽基因的作用，大多表现为白色羽毛，该基因上位掩盖了其他羽色。在本研究中，白来航鸡与东乡黑羽绿壳蛋鸡（DBBC）进行正反交，F1代所有个体均表现为白色羽毛。在F2代中，羽色分离为黑色、斑驳色和横斑图案。分析表明，横斑羽图案的分离遵循Z连锁遗传模式。在先前报道的与横斑羽图案相关的CDKN2A基因多态性中，我们发现只有SNP4适用于该群体中横斑基因的鉴定。我们还分析了横斑基因基因型与成年公鸡横斑羽色深度表型之间的相关性。将非深横斑公鸡鉴定为横斑基因纯合子的准确率为98.2%。群体检测证实横斑基因源自白来航鸡群体。当源自白来航鸡的横斑母鸡与黑羽公鸡杂交时，基于雏鸡横斑羽表型进行性别鉴定的准确率仅为89.98%。准确率降低有两个主要因素。首先，两种斑驳羽表型对横斑表型具有上位效应，在雏鸡中掩盖了横斑表型。排除斑驳雏鸡后，性别鉴定准确率提高到93.99%。其次，从白来航鸡遗传而来的横斑羽图案在雏鸡中表现出相当大的变异性，使得鉴定困难。通过采用识别雏鸡头部中线最亮白点的标准，性别鉴定准确率可进一步提高。本研究表明，伴性横斑羽基因可从白来航鸡中分离出来并用于孵化时的性别鉴定。此外，白来航鸡携带许多其他被显性上位白羽基因掩盖的羽色基因。将白来航鸡与有色羽鸡杂交可导致新羽色的分离，为育种应用提供了广阔前景。
