Analysis of SNP markers for chicken blue-shelled gene using PCR-SSCP

Abstract

AbstractThe oocyan (O) gene determines blue shell pigmentation of domesticated chicken. The O locus is closely linked to ALEV1 on chromosome 1 with a genetic distance of 2.3 cM. Blue eggshells contain a protoporphyrin, biliverdin and zinc biliverdin chelating complex, which belongs to the porphyrin metabolic pathway. A bio-informatic approach was first used to BLAST for the genes of the enzymes in the porphyrin pathway; no gene was detected to specify the O locus. Due to a limited number of simple sequence repeat (SSR) markers around the O locus, polymerase chain reaction–single-strand conformational polymorphism (PCR-SSCP) was then employed to search for candidate single nucleotide polymorphism (SNP) markers. The sequence bearing a marker was found to consist of two transversions at Chr1:61754089T→A and Chr1:61754175A→T, respectively. Population screening showed that 81% of homozygous blue-shelled layers (OO) were classified as AA genotype at the SNP loci, while 89% of heterozygous blue-shelled layers (Oo) were AB genotype and 93% of tinted layers (oo) were BB genotype. The results indicated that there is a close association between O locus and SNP locus, suggesting that the marker locus could be used as a molecular marker in breeding for blue-shelled chickens.