The Association between TYR Gene Polymorphism and Melanin Deposition in Wuding Black-boned Chicken

Purpose To study the relationship between the TYR gene polymorphism with the difference of TYR expression and melanin deposition in Wuding black-boned chicken and non-black-boned chicken.

Method Taking Wuding black-boned chicken and non-black-boned chicken as research objects, the TYR vitality, total melanin content and plasma colorimetry (OD value) in the plasma of two strains of 300 chickens at the age of 300 days was measured. Then, direct sequencing was used to analyze the polymorphic sites (SNPs) of the TYR gene exons in Wuding chickens and to detect the differences in TYR gene expression in various tissues.

Result Compared with Wuding non-black-boned chicken, Wuding black-boned chicken had higher plasma indexes. Two SNP sites (C2744T and C2866T) were found in the TYR exon region, which were in line with the Hardy-Weinberg equilibrium and showed moderate polymorphism. Compared with other genotypes, CC genotype of TYR locus C2744T showed higher TYR vitality and total melanin than other genotypes, but lower luminance value. In terms of gene expression level, TYR gene expression level in various tissues of Wuding black-boned chicken was significantly higher than that of non-black-boned chicken (P<0.01).

Conclusion CC genotype at C2744T of TYR gene can be used as genetic marker for chicken breeding of Wuding black-boned chicken, and other indicators can be used as auxiliary reference.