Polymorphism in the 5ʹ regulatory region of CTNNB1 gene and association with age at first lay and egg production

1. The Wnt signalling pathway is centred on the fact that catenin beta-1(CTNNB1) participates in the regulation of ovarian follicle development. The aim of the following study was to identify polymorphisms in the 5' regulatory region of the chicken CTNNB1 gene and evaluate the association between SNPs and egg production traits.2. The study demonstrated that the 5' regulatory region of the CTNNB1 gene has 10 SNPs in the investigated Jining Bairi chickens. After Bonferroni correction for multiple testing, five SNPs (rs315692306, 2:g43385123, rs735854102, 2:g43385457 and rs737907370) were significantly correlated with egg laying traits.3. An association study of the haplotypes with egg laying traits revealed that both haplotypes in block 1 (consisting of rs735052881, rs740662190, rs315692306, and 2:43385123) and block 2 (consisting of rs735854102 and 2:g43385457) were associated with point of lay age and the number of eggs laid at 18-23 weeks. Prediction of transcription factor-binding sites showed that transcription factors changed after mutation in block 2. The luciferase assay revealed that the priming activity of the CA haplotype in block 2 was the highest.4. Taken together, the rs315692306, 2:g43385123, rs735854102, 2:g43385457 and rs737907370 in the 5' regulatory region of the CTNNB1 gene have significant impacts on egg production.