多巴色素异构酶（dopachrome tautomerase，Dct）是酪氨酸酶家族的重要成员之一，在黑色素合成过程中具有重要作用。为了解多巴色素异构酶基因（）的“粉花”体色类型为研究对象，在对该基因进行克隆和表达分析的基础上，应用CRISPR/Cas9基因编辑技术研究了该基因对瓯江彩鲤黑斑体色的影响。结果发现，瓯江彩鲤存在2个Dct1与在“粉花”体色瓯江彩鲤的黑斑皮肤中的表达量显著高于白色皮肤，而Dct1和基因突变对瓯江彩鲤黑斑体色存在重要影响，与在鲤的黑斑体色形成中发挥着更大的作用。

Pigmentation is a widespread phenomenon in vertebrates that enables vertebrates to adapt to their environment. For example, it can improve concealment and prevent damage from ultraviolet light. Over 250 genes are known to influence the process of melanin synthesis or the formation of pigmentation patterns. Among them, the tyrosinase family genes encode the key enzyme that catalyzes melanogenesis. Dopachrome tautomerase () is a tyrosinase family member and plays a role in catalyzing 5,6-dihydroxyindole (DHI) to 5,6-dihydroxyindole-2- carboxylic acid (DHICA), which is an important substrate for melanin synthesis. However, the effect of on fish pigmentation patterns remains unclear. Common carp is an important aquatic species and there are many varieties of this fish. Oujiang color common carp () is one of these varieties and it has obvious black patches on its skin, which make them a useful material for investigating the function of the gene during pigmentation formation in common carp. In addition, multiple gene copies are common in the Cyprinidae due to additional genome duplication. The effects of copies on Oujaing color carp during melanogenesis remain unclear. The influence of on pigment pattern of black patches in the "WB" pattern of Oujiang color common carp was investigated by cloning genes and measuring their gene expression levels in black patches and white skin tissue using an RT-PCR analysis. CRISPR/Cas9 gene editing technology was used to construct highly mutated Dct mutated carps were observed. This study showed that two ) were detected in Oujiang color common carp. When their DNA sequences in the genome were compared, the results showed that both had CDS sequences that contained 1548 bp nucleotides and encoded 515 amino bases. The alignment results between showed that they had 95.55% nucleotide sequence similarity and 94.95% similarity of amino acid sequences. When they were compared to the Dct amino acid sequence in zebrafish, the results showed that shared similarities of 86.16% and 85.51% in their nucleotide sequences and 88.16% and 86.80% in their amino acid sequences, respectively. The gene expression results revealed that had different expression patterns in the black and white skin areas of the "WB" pattern Oujiang color common carp. expression was significantly higher in the black patch region than in the white skin region ( expression in the white skin areas was significantly higher than in the black patch areas ( mutated phenotype showed that, the black patch regions were smaller on the mutated fishes (mutated efficiency>50%) and there were more non-dendritic like melanocytes appeared. In conclusion, this study showed that may have similar functions during the synthesis of melanin because their amino acid sequences were almost identical. However, the RT-PCR results indicated that played a dominant role in melanogenesis due to its relatively higher expression in black patch tissue. The CRISPR/Cas9 gene editing technology results for enes influenced the pigment pattern of black patches and the morphology of melanocytes in oujiang color common carp. These results offer new insights into the functional effects of genes on pigmentation in common carp.

S917

国家自然科学基金项目（31772840）；广西科技重大专项（桂科AA17204095-7）.