HIGH EXPRESSION OF HMOX1 IN BLUE-SHELLED CHICKENS IS ASSOCIATED WITH A TG HAPLOTYPE

ABSTRACTHMOX1 is an important gene in biosynthesis of the eggshell pigment of blue eggs. Previous studies found that HMOX1 is highly expressed in the shell gland of hens laying blue eggs (BlueH) compared with hens laying brown eggs (BrownH); however, the reasons for the differential expression are unclear. In this study five single nucleotide polymorphism (SNP) in HMOX1 were genotyped in 111 BlueH and 115 BrownH. The association of haplotypes of these SNP with the blue egg phenotype was tested. Haplotype-specific expression of HMOX1 was detected in the shell gland. The interaction of sequence variants and transcription factors was analyzed using electrophoretic mobility shift assay (EMSA). A TG haplotype covering upstream 1.4 kb region of HMOX1 was significantly associated with blue eggs (p