Laboratoire Jean Perrin, UMR 8237 Sorbonne Universités, UPMC Université Paris 06, Paris, France.
Micalis Institute, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Jouy-en-Josas, France.
Science. 2018 Mar 16;359(6381):1283-1286. doi: 10.1126/science.aan0797.
Mutations have been investigated for more than a century but remain difficult to observe directly in single cells, which limits the characterization of their dynamics and fitness effects. By combining microfluidics, time-lapse imaging, and a fluorescent tag of the mismatch repair system in , we visualized the emergence of mutations in single cells, revealing Poissonian dynamics. Concomitantly, we tracked the growth and life span of single cells, accumulating ~20,000 mutations genome-wide over hundreds of generations. This analysis revealed that 1% of mutations were lethal; nonlethal mutations displayed a heavy-tailed distribution of fitness effects and were dominated by quasi-neutral mutations with an average cost of 0.3%. Our approach has enabled the investigation of single-cell individuality in mutation rate, mutation fitness costs, and mutation interactions.
突变已经被研究了一个多世纪，但在单细胞中仍然难以直接观察，这限制了对它们动力学和适应度影响的描述。通过结合微流控技术、延时成像和错配修复系统的荧光标记，我们在单个细胞中可视化了突变的出现，揭示了泊松动力学。同时，我们跟踪了单个细胞的生长和寿命，在数百代中积累了大约 20000 个全基因组的突变。这项分析表明，1%的突变是致命的；非致死性突变表现出适应度效应的长尾分布，并且主要由具有平均成本为 0.3%的准中性突变主导。我们的方法使我们能够在突变率、突变适应度成本和突变相互作用方面研究单细胞的个体性。
