Histopathological Characteristics and Multi-Omics Analysis of Ocular Pigmentation Defects in Albino Percocypris pingi

Percocypris pingi was listed in the China Vertebrate Red List in 2015, and albino P. pingi exhibits remarkable ocular phenotypes due to melanin synthesis defects, including the deficiency of melanin granules in the iris and retinal pigment epithelium (RPE). However, the regulatory mechanism of pigment loss in the eyes of albino P. pingi has not yet been clarified. This study systematically revealed the potential mechanisms underlying the obstruction of ocular melanin synthesis in albino P. pingi through histopathological analysis, transcriptomics, and proteomics techniques. The results showed that the synergistic effects of abnormal H⁺ transport mediated by SLC45A2, excessive activation of retinol metabolism, and cytoskeletal transport disorders led to the inhibition of tyrosinase activity and retention of pigment granules, ultimately causing melanin deficiency in the eyes. This study first elucidates the molecular network of ocular albinism in fish from a multi-omics perspective, providing a new perspective for the mechanistic research of pigmentation disorders in vertebrates.