Ministry of Education Key Laboratory for biodiversity science and Ecological Engineering, Department of Ecology and Evolutionary Biology, Fudan University, Shanghai, 200433, China.
Sci Rep. 2017 Sep 5;7(1):10436. doi: 10.1038/s41598-017-10596-4.
It is essential to assess environmental impact of transgene flow from genetically engineered crops to their wild or weedy relatives before commercialization. Measuring comparative trials of fitness in the transgene-flow-resulted hybrids plays the key role in the assessment, where the segregated isogenic hybrid lineages/subpopulations with or without a transgene of the same genomic background are involved. Here, we report substantial genomic differentiation between transgene-present and -absent lineages (F-F) divided by a glyphosate-resistance transgene from a crop-wild/weed hybrid population in rice. We further confirmed that such differentiation is attributed to increased frequencies of crop-parent alleles in transgenic hybrid lineages at multiple loci across the genome, as estimated by SSR (simple sequence repeat) markers. Such preferential transmission of parental alleles was also found in equally divided crop-wild/weed hybrid lineages with or without a particular neutral SSR identifier. We conclude that selecting either a transgene or neutral marker as an identifier to create hybrid lineages will result in different genomic background of the lineages due to non-random transmission of parental alleles. Non-random allele transmission may misrepresent the outcomes of fitness effects. We therefore propose seeking other means to evaluate fitness effects of transgenes for assessing environmental impact caused by crop-to-wild/weed gene flow.
在商业化之前，评估转基因作物向其野生或杂草亲缘种的基因流的环境影响至关重要。在评估中，测量转基因流导致的杂种中适应性的比较试验起着关键作用，其中涉及具有或不具有相同基因组背景的转基因的分离同基因杂种谱系/亚群。在这里，我们报告了在水稻作物-野生/杂草杂种群体中，由草甘膦抗性转基因划分的转基因存在和不存在谱系（F-F）之间存在大量的基因组分化。我们进一步证实，这种分化归因于在多个基因组位点上，转基因为转基因杂种谱系中的作物亲本等位基因的频率增加，这是通过 SSR（简单重复序列）标记估计的。在具有或不具有特定中性 SSR 标识符的等分作物-野生/杂草杂种谱系中，也发现了这种亲本等位基因的优先传递。我们得出结论，选择转基因或中性标记作为标识符来创建杂种谱系，由于亲本等位基因的非随机传递，将导致谱系的不同基因组背景。非随机等位基因传递可能会错误表示适应性效应的结果。因此，我们建议寻求其他方法来评估转基因的适应性效应，以评估由作物向野生/杂草基因流引起的环境影响。
