RNA sequencing analysis reveals that missense mutation in SOX10 is associated with iris color phenotype in quail.

To investigate the molecular mechanisms underlying the differences in iris color in quail, the transcriptome of iris tissue from black quail and Korean quail at day 10 of hatching was RNA sequenced in this study. The differentially expressed genes (DEGs) were screened, functionally annotated and enriched after the quality control and mapping of the raw data. RT-qPCR validation was performed using EIF2S3 as an internal reference gene. The screened SNPs were studied by bioinformatics analysis and iris color correlation analysis. The results showed that there were 425 upregulated genes and 364 downregulated genes in 789 DEGs. Gene Ontology (GO) enrichment analysis revealed that 139 DEGs were significantly enriched in 154 GO terms. The Kyoto Encyclopedia of Genes and Genomes enrichment results showed that the Notch signaling pathway, melanogenesis and tyrosine metabolism were associated with pigment synthesis (p < 0.05). The expression levels of the ASIP, MLPH, PMEL, TYR and SOX10 genes were significantly different in black quail iris and Korean quail iris, as verified by RT-qPCR. The SOX10 gene c.324G>C mutation, which caused the replacement of p.Glu108Asp, had a highly significant correlation with iris color in black quail and Korean quail, which may be one of the reasons for different in iris color between these two quail species.