Sex-specific DNA markers are powerful tools for genetic sex identification and sex control breeding of fish. Spotted halibut () is a kind of marine flatfish with important nutritional and economic value, which exhibits significant sex-related growth dimorphism that the female individuals grow faster than the male individuals. However, there is no rapid, effective and universal sex-specific DNA marker used for genetic sex identification and sex control breeding in spotted halibut up to date. In the present study, whole genome resequencing was performed on 17 male and 17 female spotted halibut individuals to identify sex-specific markers. A total of 325.36 Gb and 328.99 Gb data were obtained from females and males, respectively. After reads mapping, sequencing depth and coverage analysis, 359 potential female-specific DNA sequences were identified. Then, after two rounds of verification, two female-specific 66 bp and 68 bp insertions were identified as female-specific markers which can accurately identify the genetic sex of spotted halibut through PCR amplification and 2% agarose gel electrophoresis. Subsequently, these two female-specific DNA markers and the PCR method were further validated using 117 spotted halibut individuals from another breeding population to confirm their genetic sex, which was in accordance with their phenotypic sex determined by histological section of the gonads. This may be the first two rapid, accurate and effective female-specific DNA markers used for genetic sex identification in spotted halibut. The identification of these two female-specific DNA markers will not only provide important genetic evidence to elucidate the sex determination mechanism of spotted halibut, but also help to advance the process of sex control breeding in spotted halibut.

中文翻译：

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斑鲽两个雌性特异性 DNA 标记的鉴定

性别特异性 DNA 标记是鱼类遗传性别鉴定和性别控制育种的有力工具。斑点大比目鱼是一种具有重要营养和经济价值的海洋比目鱼，表现出显着的性别相关生长二态性，雌性个体生长速度快于雄性个体。然而，目前尚无快速、有效、通用的性别特异性DNA标记用于斑点大比目鱼的遗传性别鉴定和性别控制育种。在本研究中，对 17 只雄性和 17 只雌性斑点大比目鱼个体进行了全基因组重测序，以确定性别特异性标记。从女性和男性中分别获得了总计 325.36 Gb 和 328.99 Gb 的数据。经过读段作图、测序深度和覆盖度分析后，鉴定出了 359 个潜在的女性特异性 DNA 序列。然后，经过两轮验证，确定了两个雌性特异的66 bp和68 bp插入片段作为雌性特异性标记，通过PCR扩增和2%琼脂糖凝胶电泳可以准确鉴定斑比目鱼的遗传性别。随后，使用来自另一个繁殖群体的 117 只斑点大比目鱼个体进一步验证了这两个雌性特异性 DNA 标记和 PCR 方法，以确认其遗传性别，这与通过性腺组织学切片确定的表型性别一致。这可能是第一个用于斑点大比目鱼遗传性别鉴定的快速、准确和有效的雌性特异性 DNA 标记。这两个雌性特异性DNA标记的鉴定不仅将为阐明斑比目鱼性别决定机制提供重要的遗传证据，也有助于推进斑比目鱼性别控制育种进程。