A resurrection experiment finds evidence of both reduced genetic diversity and potential adaptive evolution in the agricultural weed Ipomoea purpurea

Despite the negative economic and ecological impact of weeds, relatively little is known about the evolutionary mechanisms that influence their persistence in agricultural fields. Here, we use a resurrection approach to examine the potential for genotypic and phenotypic evolution in Ipomoea purpurea, an agricultural weed that is resistant to glyphosate, the most widely used herbicide in current-day agriculture. We found striking reductions in allelic diversity between cohorts sampled nine years apart (2003 vs. 2012), suggesting that populations of this species sampled from agricultural fields have experienced genetic bottleneck events that have led to lower neutral genetic diversity. Heterozygosity excess tests indicate that these bottlenecks may have occurred prior to 2003. A greenhouse assay of individuals sampled from the field as seed found that populations of this species, on average, exhibited modest increases in herbicide resistance over time. However, populations differed signif...尽管杂草会对农业生产造成负面的经济与生态影响，但学界对影响其在农田中存续的进化机制仍知之甚少。本研究采用复活采样法（resurrection approach），针对抗当前农业生产中应用最广泛的除草剂草甘膦（glyphosate）的农田杂草圆叶牵牛（Ipomoea purpurea）开展研究，以探究其基因型与表型进化的潜力。我们发现，间隔9年采集的两批样本（2003年与2012年）之间，等位基因多样性出现了显著下降，这表明该物种的农田种群曾经历遗传瓶颈事件，进而导致中性遗传多样性水平降低。杂合子过量检验（heterozygosity excess tests）结果显示，此类遗传瓶颈可能发生于2003年之前。对田间采集的种子个体开展的温室实验显示，该物种的种群平均而言随时间推移除草剂抗性出现小幅提升。不过不同种群之间存在显著……