Nielsen Kaare M, Townsend Jeffrey P
Department of Pharmacy, Faculty of Medicine, University of Tromsø, N9037 Tromsø, Norway.
Nat Biotechnol. 2004 Sep;22(9):1110-4. doi: 10.1038/nbt1006.
Monitoring efforts have failed to identify horizontal gene transfer (HGT) events occurring from transgenic plants into bacterial communities in soil or intestinal environments. The lack of such observations is frequently cited in biosafety literature and by regulatory risk assessment. Our analysis of the sensitivity of current monitoring efforts shows that studies to date have examined potential HGT events occurring in less than 2 g of sample material, when combined. Moreover, a population genetic model predicts that rare bacterial transformants acquiring transgenes require years of growth to out-compete wild-type bacteria. Time of sampling is there-fore crucial to the useful implementation of monitoring. A population genetic approach is advocated for elucidating the necessary sample sizes and times of sampling for monitoring HGT into large bacterial populations. Major changes in current monitoring approaches are needed, including explicit consideration of the population size of exposed bacteria, the bacterial generation time, the strength of selection acting on the transgene-carrying bacteria, and the sample size necessary to verify or falsify the HGT hypotheses tested.
监测工作未能识别出转基因植物向土壤或肠道环境中的细菌群落发生水平基因转移（HGT）的事件。生物安全文献以及监管风险评估中经常提及缺乏此类观察结果。我们对当前监测工作敏感性的分析表明，迄今为止的研究在合并样本时，所检测的潜在HGT事件发生在少于2克的样本材料中。此外，一个群体遗传模型预测，获得转基因的罕见细菌转化体需要数年时间生长才能胜过野生型细菌。因此，采样时间对于监测的有效实施至关重要。提倡采用群体遗传方法来阐明监测向大量细菌群体的HGT所需的样本量和采样时间。需要对当前监测方法进行重大改变，包括明确考虑暴露细菌的群体大小、细菌世代时间、作用于携带转基因细菌的选择强度，以及验证或证伪所测试的HGT假设所需的样本量。
