Paralichthys olivaceus is the kind of cold-water benthic marine fish. In the early stages of development, the symmetrical juveniles transform into an asymmetrical body shape through metamorphosis for adapting benthic life. After that, one side of the fish body is attached to the ground, and the eyes turn to the opposite side which is called ocular side. The body color also appears asymmetry. The skin on the ocular side is dark brown, and the skin on the blind side is white without pigmentation. Pseudo-albinism and hypermelanosis have been considered distinct body color disorders in flatfish. Pseudo-albinism and hypermelanosis in Paralichthys olivaceus are due to abnormal or uneven pigment distribution, due to the interaction of hereditary and environmental factors, rather than a single-nucleotide mutation of a specific gene. Here, we report three single-nucleotide polymorphisms (SNPs) responsible for both pseudo-albinism and hypermelanosis, which are located on two body color-related genes involved in melanogenesis-related pathways. c.2440C>A (P. V605I) and c.2271-96T>C are located on the Inositol 1,4,5-trisphosphate receptor type 2-like (ITPR2) (Gene ID: 109624047), they are located in exon 16 and the non-coding region, respectively, and c.2406C>A (P.H798N) is located in exon 13 of the adenylate cyclase type 6-like (AC6) gene(Gene ID: 109630770). ITPR2 and AC6 expression, which both participate in the thyroid hormone synthesis pathway associated with pseudo-albinism and hypermelanosis in P. olivaceus, were also investigated using qRT-PCR. In hypermelanotic fish, there were relatively higher levels of expression in ITPR2 and AC6 mRNA of hyper-pigmented skin of blind side than that of non-pigmented skin on the blind side and pigmented skin on the ocular side, while in pseudo-albino fish, expression level of ITPR2 and AC6 mRNA in pigmented skin of ocular side was significantly higher than that in non-pigmented skin both ocular and blind side. The results indicated that the expression of the two genes in abnormal parts of body color is positively correlated with pigmentation, suggesting that the influence of abnormal expression of two genes on the pigmentation in abnormal parts of body color deserves further study.

淡水Paralichthys olivaceus是一种冷水底栖海鱼。在发展的早期，对称的幼体通过变态转变为不对称的身体形状，以适应底栖生物的生活。之后，鱼体的一侧附着在地面上，眼睛转向另一侧，称为眼侧。车身颜色也显示为不对称。眼侧的皮肤为深棕色，而盲侧的皮肤为白色，无色素沉着。伪白化病和黑色素沉着症被认为是比目鱼独特的体色异常。伪白化病和hypermelanosis在牙鲆这是由于色素分布异常或不均匀，由于遗传和环境因素的相互作用，而不是特定基因的单核苷酸突变引起的。在这里，我们报告负责伪白化病和黑色素过多症的三个单核苷酸多态性（SNPs），它们位于参与黑素生成相关途径的两个与身体颜色相关的基因上。c.2440C> A（P. V605I）和c.2271-96T> C位于肌醇1,4,5-三磷酸受体2型（ITPR2）（基因ID：109624047）上，它们位于外显子上c.2406C> A（P.H798N）分别位于16和非编码区，并位于6样腺苷酸环化酶（AC6）基因（基因编号：109630770）。ITPR2和AC6表达，其中两个参与与在伪白化病和相关联hypermelanosis甲状腺激素合成途径牙鲆，使用qRT-PCR的还研究。在黑色素沉着鱼中，与没有色素沉着的皮肤和眼睛有色素的皮肤相比，在色素沉着侧的色素沉着皮肤的ITPR2和AC6 mRNA的表达水平相对较高，而在伪白化鱼中，ITPR2和AC6的表达水平眼侧和盲侧的有色皮肤的mRNA显着高于无色素的皮肤。结果表明，这两个基因在人体颜色异常部位的表达与色素沉着呈正相关，这表明两个基因的异常表达对人体颜色异常部位的色素沉着的影响值得进一步研究。