In mammals the colour of skin is due to production of eumelanins (brown-black pigments) and pheomelanins (yellow-brownish pigments) in a specific type cell, the melanocytes. In contrast, in fish, pigmentation patternare determine by three different types of cells, melanophores, xantophores and iridophores. However, in both cases the melanogenesis is controlled by a similar mechanism. The α-MSH which stimulate the synthesis of melanin, and the ASP which antogonize its effects. Flounder (Scophthalmus maximus L.) agouti gen was cloned from skin tissue by using RACE-PCR with degenerated oligos. High expression of agouti gene was found in white epidermis areas compared with the black ones. Furthermore, dermal-injection of capped agouti mRNA produced a striking skin lightening. Thus, suggesting a central role of agouti gene in pigmentation pattern control in fish
