Stearns Frank W, Fenster Charles B
Department of Biology Biology-Psychology Building University of Maryland College Park MD USA.
Ecol Evol. 2016 Oct 24;6(23):8366-8374. doi: 10.1002/ece3.2558. eCollection 2016 Dec.
Mutations are the ultimate source of all genetic variations. New mutations are expected to affect quantitative traits differently depending on the extent to which traits contribute to fitness and the environment in which they are tested. The dogma is that the preponderance of mutations affecting fitness will be skewed toward deleterious while their effects on nonfitness traits will be bidirectionally distributed. There are mixed views on the role of stress in modulating these effects. We quantify mutation effects by inducing mutations in (Columbia accession) using the chemical ethylmethane sulfonate. We measured the effects of new mutations relative to a premutation founder for fitness components under both natural (field) and artificial (growth room) conditions. Additionally, we measured three other quantitative traits, not expected to contribute directly to fitness, under artificial conditions. We found that induced mutations were equally as likely to increase as decrease a trait when that trait was not closely related to fitness (traits that were neither survivorship nor reproduction). We also found that new mutations were more likely to decrease fitness or fitness-related traits under more stressful field conditions than under relatively benign artificial conditions. In the benign condition, the effect of new mutations on fitness components was similar to traits not as closely related to fitness. These results highlight the importance of measuring the effects of new mutations on fitness and other traits under a range of conditions.
突变是所有遗传变异的最终来源。新的突变预计会对数量性状产生不同的影响，这取决于性状对适合度的贡献程度以及测试它们的环境。教条认为，影响适合度的突变大多会偏向有害，而它们对非适合度性状的影响将呈双向分布。关于压力在调节这些影响中的作用存在不同观点。我们通过使用化学物质甲基磺酸乙酯在（哥伦比亚种质）中诱导突变来量化突变效应。我们在自然（田间）和人工（生长室）条件下测量了相对于突变前奠基者的新突变对适合度成分的影响。此外，我们在人工条件下测量了其他三个预计不会直接影响适合度的数量性状。我们发现，当性状与适合度关系不密切时（既不是生存也不是繁殖的性状），诱导突变增加或减少性状的可能性相同。我们还发现，与相对温和的人工条件相比，在压力更大的田间条件下，新突变更有可能降低适合度或与适合度相关的性状。在温和条件下，新突变对适合度成分的影响与与适合度关系不那么密切的性状相似。这些结果突出了在一系列条件下测量新突变对适合度和其他性状影响的重要性。
