Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, València, Spain.
J Evol Biol. 2010 Nov;23(11):2453-60. doi: 10.1111/j.1420-9101.2010.02107.x. Epub 2010 Sep 9.
Mutational robustness has important evolutionary implications, yet the mechanisms leading to its emergence remain poorly understood. One possibility is selection acting on a correlated trait, as for instance thermostability (plastogenetic congruence). Here, we examine the correlation between mutational robustness and thermostability in experimental populations of the RNA bacteriophage Qβ. Thermostable viruses evolved after only six serial passages in the presence of heat shocks, and genome sequencing suggested that thermostability can be conferred by several alternative mutations. To test whether thermostable viruses have increased mutational robustness, we performed additional passages in the presence of nitrous acid. Whereas in control lines this treatment produced the expected reduction in growth rate caused by the accumulation of deleterious mutations, thermostable viruses showed no such reduction, indicating that they are more resistant to mutagenesis. Our results suggest that selection for thermostability can lead to the emergence of mutational robustness driven by plastogenetic congruence. As temperature is a widespread selective pressure in nature, the mechanism described here may be relevant to the evolution of mutational robustness.
突变稳健性具有重要的进化意义，但导致其出现的机制仍知之甚少。一种可能性是选择作用于相关性状，例如热稳定性（表型协同进化）。在这里，我们研究了 RNA 噬菌体 Qβ的实验种群中突变稳健性和热稳定性之间的相关性。在存在热冲击的情况下，仅经过六次连续传代就进化出了耐热病毒，基因组测序表明耐热性可以通过几种替代突变来赋予。为了测试耐热病毒是否具有更高的突变稳健性，我们在亚硝酸存在的情况下进行了额外的传代。在对照系中，这种处理会因有害突变的积累而导致预期的生长速率降低，但耐热病毒没有出现这种降低，表明它们对诱变更具抵抗力。我们的结果表明，耐热性的选择可以导致由表型协同进化驱动的突变稳健性的出现。由于温度是自然界中广泛存在的选择压力，因此这里描述的机制可能与突变稳健性的进化有关。
