Fitness effects of new mutations in Chlamydomonas reinhardtii across two stress gradients.
Fitness effects of new mutations in Chlamydomonas reinhardtii across two stress gradients.
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DOI：
10.1111/jeb.12807
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发表时间：
2016-03
影响因子：
2.1
通讯作者：
Colegrave N
中科院分区：
文献类型：
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作者：
Kraemer SA;Morgan AD;Ness RW;Keightley PD;Colegrave N
大多数影响适应性的自发突变可能是有害的，但作用于它们的选择强度可能受到环境压力的影响。这种压力依赖的选择可能会暴露隐藏的遗传变异，这反过来可能会增加压力种群的适应潜力。另一方面，这种变异可能代表遗传负荷，从而导致压力下的种群灭绝。然而，以前的研究确定了压力和突变对适应性的影响之间的联系，产生了不一致的结果。在这里，我们确定了健身的净变化，在29个基因型的绿色藻类莱茵衣藻，积累突变，在几乎没有选择约1000代跨越两个应力梯度，增加NaCl和减少磷酸盐。我们发现突变效应在极端压力条件下会被放大，但这种效应既取决于压力类型，也取决于遗传背景。突变的压力依赖适应性效应的检测取决于通过世代时间精确地缩放相对适应性度量，从而为先前研究之间的不一致提供了解释。
Most spontaneous mutations affecting fitness are likely to be deleterious, but the strength of selection acting on them might be impacted by environmental stress. Such stress‐dependent selection could expose hidden genetic variation, which in turn might increase the adaptive potential of stressed populations. On the other hand, this variation might represent a genetic load and thus lead to population extinction under stress. Previous studies to determine the link between stress and mutational effects on fitness, however, have produced inconsistent results. Here, we determined the net change in fitness in 29 genotypes of the green algae Chlamydomonas reinhardtii that accumulated mutations in the near absence of selection for approximately 1000 generations across two stress gradients, increasing NaCl and decreasing phosphate. We found mutational effects to be magnified under extremely stressful conditions, but such effects were specific both to the type of stress and to the genetic background. The detection of stress‐dependent fitness effects of mutations depended on accurately scaling relative fitness measures by generation times, thus offering an explanation for the inconsistencies among previous studies.