National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India.
International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bangalore, India.
Evolution. 2021 May;75(5):1201-1217. doi: 10.1111/evo.14179. Epub 2021 Feb 2.
Phenotypic variation is widespread in natural populations, and can significantly alter population ecology and evolution. Phenotypic variation often reflects underlying genetic variation, but also manifests via non-heritable mechanisms. For instance, translation errors result in about 10% of cellular proteins carrying altered sequences. Thus, proteome diversification arising from translation errors can potentially generate phenotypic variability, in turn increasing variability in the fate of cells or of populations. However, the link between protein diversity and phenotypic variability remains unverified. We manipulated mistranslation levels in Escherichia coli, and measured phenotypic variability between single cells (individual-level variation), as well as replicate populations (population-level variation). Monitoring growth and survival, we find that mistranslation indeed increases variation across E. coli cells, but does not consistently increase variability in growth parameters across replicate populations. Interestingly, although any deviation from the wild-type (WT) level of mistranslation reduces fitness in an optimal environment, the increased variation is associated with a survival benefit under stress. Hence, we suggest that mistranslation-induced phenotypic variation can impact growth and survival and has the potential to alter evolutionary trajectories.
表型变异在自然种群中广泛存在，可显著改变种群生态和进化。表型变异通常反映潜在的遗传变异，但也通过非遗传性机制表现出来。例如，翻译错误导致约 10%的细胞蛋白携带改变的序列。因此，翻译错误引起的蛋白质组多样化可能潜在地产生表型可变性，进而增加细胞或种群命运的可变性。然而，蛋白质多样性与表型可变性之间的联系仍未得到验证。我们在大肠杆菌中操纵错译水平，并测量单细胞之间的表型可变性（个体水平的变异），以及复制种群（种群水平的变异）。监测生长和存活，我们发现错译确实增加了大肠杆菌细胞之间的变异性，但并不总是增加复制种群中生长参数的变异性。有趣的是，尽管任何偏离野生型（WT）错译水平的水平都会降低在最佳环境中的适应性，但增加的变异性与应激下的生存益处相关。因此，我们认为，错译诱导的表型可变性可能会影响生长和存活，并有可能改变进化轨迹。
