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Variation in the ovocalyxin‐32 gene in commercial egg‐laying chickens and its relationship with egg production and egg quality traits
Author(s) -
Fulton J. E.,
Soller M.,
Lund A. R.,
Arango J.,
Lipkin E.
Publication year - 2012
Publication title -
animal genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 81
eISSN - 1365-2052
pISSN - 0268-9146
DOI - 10.1111/j.1365-2052.2012.02384.x
Subject(s) - eggshell , biology , genetics , gene , exon , yolk , snp , single nucleotide polymorphism , candidate gene , zoology , genotype , food science , ecology
Summary Avian eggshell quality is an important trait for commercial egg production, as the eggshell is the primary packaging material and antimicrobial barrier for the internal food resource. Strong eggshells are essential to ensure that eggs can reach their final destination without damage. Ovocalyxin‐32 ( OCX 32) is a matrix protein found within the outer layers of the eggshell and in the cuticle. Numerous reports in the literature have identified association between variants in the gene encoding this protein, OCX32 , and various eggshell quality traits. Thus, OCX32 is a candidate gene for selection for eggshell traits in commercial poultry populations. Sequencing of exons 2–6 of the OCX32 gene in eight elite brown and white eggshell commercial egg‐laying lines revealed 28 SNP s and one SNP /indel. Eighteen of these SNP s were predicted to alter the amino acid sequence of the protein. Clusters of SNP s in complete linkage disequilibrium were found in both exons 2 and 6. A total of 19 different versions or protein‐sequence haplotypes of the OCX 32 protein were inferred, revealing considerable variation within commercial lines. Genotypes for 13 of the SNP s were determined for 330–1819 individuals per line. Trait association studies revealed a significant effect of OCX 32 on shell color in white egg lines and line‐specific significant effects on albumen height, early egg weight, puncture score, and yolk weight. Three of the lines showed a significant change in OCX32 frequency over time, indicating selection pressure for certain variants of this gene during the breeding program.