The Polymorphism of Agouti Signaling Protein Gene(Agouti) and the Expression of Agouti and Microphthalmia-associated Transcription Factor Gene MITF in Different Coat Color Skin Tissues of Tibetan Sheep (Ovis aries)
Abstract：In order to study the molecular mechanism that determines the formation of the coat color in different coat color of Tibetan sheep(Ovis aries) skin tissues, agouti signaling protein gene(Agouti) as the main candidate gene about coat color, Agouti gene's polymorphisms were detected firstly, then associated coat color with the exon 2, exon 4 function mutations and the gene copy number variation(CNV) of Agouti, as well as the Real-time fluorescent quantitative PCR was adopted to detect mRNA's relative expression quantity of Agouti gene and microphthalmia-associated transcription factor gene(MITF), so as to analyze the discrepancy of relative expression quantity of the same gene in different skin tissue with different coat color and then had a correlation analysis of mRNA expression quantity of the two genes in the same parts of the same individual. The results showed that there was no correlation between Agouti gene exon's SNP polymorphism and coat color, so did the CNV of Agouti gene and coat color. Brown was significantly higher than that of other color skin tissue in mRNA expression of Agouti gene (P<0.05), mRNA expression quantity of MITF gene in black skin tissue had a great difference to other color skin tissue (P<0.05). Through correlation analysis, there was no significant correlation for mRNA's relative expression value of both genes in the same color of skin tissue of the same individual. The results presumed that the polymorphism of Agouti gene may have no evident correlation to the coat color of Tibetan sheep. the mRNA expression of MITF gene of the skin tissue around the eye socket plays a certain role in the formation of the black coat color of Tibetan sheep. mRNA expression of Agouti and MITF genes may have to do with the black brown hair; mRNA expression of Agouti and MITF genes has no evident correlation to the white hair, respectively.
