A Recessive oca2 Mutation Underlies Albinism in Xiphophorus fish.

Oculocutaneous albinism (OCA) is a group of genetic disorders characterized by impaired melanin production, leading to reduced pigmentation in the skin, hair, and eyes. Xiphophorus , a genus of small freshwater fish, has been a pivotal model organism in pigmentation disorder research, providing key findings in the genetic pathways governing physiological and pathological pigment cell biology. Leveraging the well-established research framework provided by Xiphophorus , we have identified a spontaneously occurring albinism phenotype in swordtail fish Xiphophorus hellerii . Genetic mapping of albino fish showed that albinism is associated with a recessive mutation in the oca2 gene. This discovery provides a novel opportunity to explore functions of oca2 gene in pigment cell differentiation, pigment synthesis, melanosome assembly and transportation function and amelanotic melanoma development.