The intensely studied white gene is widely used as a genetic marker in Drosophila melanogaster. Here, we cloned and characterized the white gene in an important pest of the fruit industry, Bactrocera dorsalis, to understand its functional role in pigmentation. We obtained BdWhite knockout strains, based on the wild‐type strain, using the CRISPR/Cas9 genome editing system, and found that mutants lost pigmentation in the compound eye and their black head spots. We then examined differences in the expression levels of genes associated with melanin pigmentation between mutants and the wild‐type strain using quantitative reverse transcription PCR. We found that transcription levels of the Bd‐yellow1 were lower in the head of mutants than in the wild‐type strain, and there were no significant differences in expression of the other six genes between mutants and the wild type. Since yellow is critical for melanin biosynthesis (Heinze et al., Scientific Reports. 2017;7:4582), the lower levels of expression of Bd‐yellow1 in mutants led to reduced dark pigmentation in head spots. Our results provide the first evidence, to our knowledge, that white may play a functional role in cuticle pigmentation by affecting the expression of yellow.

中文翻译：

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CRISPR / Cas9介导的眼睛色素沉着基因白色的敲除导致东方实蝇Bactrocera dorsalis头斑颜色的改变。

经过深入研究的白色基因被广泛用作果蝇的遗传标记。在这里，我们在水果行业的一种重要害虫Bactrocera dorsalis中克隆并鉴定了白色基因，以了解其在色素沉着中的功能。我们使用CRISPR / Cas9基因组编辑系统获得了基于野生型菌株的BdWhite基因敲除菌株，发现突变体在复眼和黑头斑中失去了色素沉着。然后，我们使用定量逆转录PCR检测了突变体与野生型菌株之间与黑色素色素沉着相关的基因表达水平的差异。我们发现Bd-yellow1的转录水平突变体的头部比野生型菌株低，并且突变体和野生型之间其他六个基因的表达没有显着差异。由于黄色对于黑色素的生物合成至关重要（Heinze等人，Scientific Reports .2017 ; 7：4582），因此Bd-yellow1在突变体中的较低表达水平导致头斑暗色素沉着减少。据我们所知，我们的结果提供了第一个证据，表明白色可能通过影响黄色的表达而在角质层色素沉着中起作用。