Revealing the genetic blueprint: A transcriptomic approach to deciphering blue iris color formation in Nili-Ravi...

Water buffalo are economically significant livestock worldwide, yet the genetic basis of the blue iris in Nili-Ravi buffalo remains elusive. We collected mixed iris-lens samples from two Murrah buffaloes (black iris) and two Nili-Ravi buffaloes (blue iris) and performed paired-end RNA-seq. After quality control, 64.53 Gb of high-quality data (Q30 ≥ 89.92 %) were obtained. Differential analysis (DESeq2,|log₂FoldChange| ≥ 2 and padj < 0.05) revealed 1,289 differentially expressed genes and 248 differentially expressed lncRNAs between blue and black irises. GO and KEGG enrichment highlighted melanogenesis, tyrosine metabolism, cysteine metabolism, and phototransduction pathways. Key differential genes related to eye development and melanin production-including the hub mRNAs KIT, MGST1, GNGT1, and TYRP1-were identified. Network analysis further showed that lncRNA MSTRG.14079.1 directly targets protein tyrosine phosphatase receptor T (PTPRT), and this interaction is significantly down-regulated in blue irises. Together, our study provides the first molecular network underlying the blue iris phenotype and establishes a theoretical basis for using this non-invasive marker to enhance breeding efficiency in buffalo.