【作者】 欧密； 茅华华； 陈昆慈； 徐红艳；

【Author】 OUMI;MAO Huahua;CHEN Kunci;XU Hongyan;Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences;

【机构】 农业部热带亚热带水产资源利用与养殖重点实验室中国水产科学研究院珠江水产研究所；

【摘要】 为了阐明乌鳢和斑鳢杂交子代乌斑鳢(乌鳢♀×斑鳢♂)杂种优势形成的分子机制,本研究运用荧光定量PCR技术检测了乌、斑鳢自交子代及其杂交子代早期胚胎发育过程中DNA甲基转移酶基因Dnmt3a的m RNA表达谱;并利用甲基化敏感扩增多态性(MSAP)技术分析了三种鱼早期胚胎过程中基因组DNA的甲基化水平变化。结果显示:三种鱼的Dnmt3a基因m RNA从受精后12小时(12 hpf)胚胎开始表达,其表达水平并随着胚胎的发育而升高;MSAP分析发现孵化出膜仔鱼DNA甲基化水平随着其发育的进行而升高,在孵化1天(24 hpf)、2天(48 hpf)和3天(72 hpf)的仔鱼中,乌鳢仔鱼的DNA甲基化水平分别为0.2571、0.3066、0.3023,斑鳢仔鱼为0.2575、0.2986、0.3045,乌斑鳢仔鱼为0.2542、0.2843、0.2805,杂交仔鱼的DNA甲基化程度显著低于自交仔鱼。另外,本研究通过比较分析三种鱼早期胚胎发育过程中Dnmt3a的表达谱及基因组甲基化水平的变化,初步确定了Dnmt3a表达水平、鱼类早期发育基因组DNA甲基化水平与乌斑鳢杂种优势形成的关系。研究结果为进一步探讨Dnmt3a基因对鱼类早期发育过程中DNA甲基化的调控作用以及甲基化对鱼类杂种优势形成的作用奠定了前期基础。更多还原

【Abstract】 To demonstrate the mechanisms behind the transgressive heterosis of Channa argus♀×Channa maculate♂(WB) hybrids, the m RNA expression level of Dnmt3 a in different developmental stages of C. argus(WW), C. maculate(BB) and WB hybrids were analyzed through real-time q PCR. Likewise, the DNA methylation level in fries were evaluated by the technique of methylation-sensitive amplified polymorphism(MSAP). The results showed that the Dnmt3 a m RNA expression was initiated in embryos at 12 hpf and increased with the developing of embryos from inbred and hybrid groups. Similarly, through the MSAP analysis, it was found that the DNA methylation level of fry from all three groups were gradually elevated as fry develop(24 hpf, 48 hpf and 72 hpf): in the WW fry, the DNA methylation level was assessed as 0.2571, 0.3066, 0.3023, respectively; in the BB fry, it was 0.2575, 0.2986, 0.3045, respectively; in the WB fry, it was 0.2656, 0.2843, 0.2805. At all the stages tested in this study, the DNA methylation levels of hybrid fry was apparently lower than those of inbred fry. Additionally, through comparative analysis on the dnmt3 a m RNA expression profiles and the DNA methylation status among three group fry, the potential modulation of dnmt3 a gene on DNA methylation of fish embryo was evaluated, and the correlation between the DNA methylation and transgressive heterosis was assessed. The findings of present provide a basis for further investigations on the functions of dnmt3 a gene in DNA methylation during embryogenesis, as well as the modulation of DNA methylation on the formation of transgressive heterosis in fish hybrid fry.更多还原