Pedigree reconstruction based on genotype data in chickens

A reliable pedigree serves as the backbone of genetic evolution in domesticated animals, providing guidance for daily management and breeding strategies. However, in commercial chicken breeding, pedigree errors and omissions are common. The large-scale application of genomic selection provides an opportunity to reconstruct chicken pedigrees using SNP markers. Here, to reconstruct pedigrees in chickens, we detected high-quality SNPs from 2866 parent-offspring pairs and calculated their genomic relationship and identity by descent (IBD). The results showed that the IBD values for parent-offspring pairs ranged from 0.48 to 0.58, clearly distinguishing them from nonparent-offspring pairs and demonstrating robustness in parentage assignment. In contrast, the genomic relatedness coefficients varied from 0.32 to 0.65. The accuracy of pedigree reconstruction significantly improved as the SNP number and minor allele frequency (MAF) increased. When the number of SNPs exceeded 200, better inference power was exhibited with IBD than with genomic relatedness. Upon reaching an effective SNP quantity of 350, despite a MAF of 0.01, the accuracy of the pedigrees inferred reached a remarkable level of 99%. Furthermore, with a doubled SNP quantity of 700 and a MAF of 0.05, the accuracy increased to a perfect 100%. This study demonstrated the feasibility of accurately constructing pedigrees in chickens using low-density SNP markers and emphasized the importance of considering the number and MAFs of these markers to achieve optimal outcomes. The adoption of the IBD as a suitable metric for pedigree inference is promising for improving the efficiency and accuracy of genetic breeding programs. These findings are paramount for the development of cost-effective yet accurate parentage verification systems.