Expression analysis and single-nucleotide polymorphisms of MLPH and PMEL17 genes associated with melanin deposition in Xuefeng black-bone chickens

Melanin deposition related genes such as MLPH and PMEL17 play an important role in black-bone chicken. This study was aimed to identify and associate SNPs in the MLPH and PMEL17 genes with melanin content of pectoral muscle (MCPM) in Xuefeng black-bone chicken. A total of 120 Xuefeng black-bone chickens at 120-day-old were randomly selected to measure blackness of pectoral muscle (BPM), according to the degree of BPM selected 22 high blackness (HB) and 22 low blackness (LB) chickens to determine the MCPM, and extract DNA and mRNA. The results indicated that the MCPM in the HB group was higher than in the LB group (P < 0.01), and the L value in the HB group was lower than in the LB group (P < 0.01). And we measured the mRNA expression levels of MLPH and PMEL17 genes in pectoral muscle by quantitative real-time PCR. The results revealed that the mRNA expression levels of MLPH gene (P < 0.05) and PMEL17 gene (P < 0.01) in the HB group was higher than in the LB group, and the mRNA relative expression level of MLPH and PMEL17 genes with MCPM was positive correlation (P < 0.01). And the sequencing results found that a total of 17 SNPs were found in MLPH gene, the C-1411T was associated with MCPM (P < 0.05), there was no difference in MCPM among other locus (P > 0.05). And there were 10 SNPs in PMEL17 gene, the G-1843C, C-2812T, and G-2794A were associated with MCPM (P < 0.05), there was no difference in the MCPM among other locus (P > 0.05). These SNPs could be molecular markers for breeding selection of blackness traits.