Environmental effects on genetic variance are likely to constrain adaptation in novel environments
Environmental effects on genetic variance are likely to constrain adaptation in novel environments
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DOI：
10.1093/evlett/qrad065
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发表时间：
2024-01-18
影响因子：
5
通讯作者：
Bridle，Jon
中科院分区：
文献类型：
--
作者：
Walter，Greg M.;Monro，Keyne;Bridle，Jon
适应性可塑性使种群能够科普环境变化，但随着条件变得不熟悉，预计会失败。在新的条件下，种群可能会依赖快速适应来增加适应性并避免灭绝。当可塑性和选择都发生在包含丰富遗传变异的多变量表型方向时，适应应该是最快的。然而，从现场实验中对这一预测进行检验的情况很少。在这里，我们量化了多变量表型中的加性遗传方差如何在海拔梯度上变化，并测试可塑性和选择是否与遗传变异一致。我们这样做使用两个密切相关的，但生态上不同的，姐妹种西西里雏菊（千里光，菊科）适应高海拔和低海拔的山。埃特纳。使用定量遗传育种设计，我们产生，然后种植c。两个物种的19，000粒种子，跨越跨越每个物种的原生海拔的海拔梯度，然后量化死亡率和出苗幼苗的五个叶性状。我们发现，叶性状的遗传变异在海拔之间的变化比在物种之间的变化更大。在新的低海拔高海拔物种的叶性状之间的遗传方差分布的变化，这减少了选择和本地表型的方向的遗传方差的量。与此相反，低海拔物种主要表现在新的高海拔的遗传变异量的变化，遗传变异集中在本地表型的方向。对于这两个物种，叶性状可塑性海拔是在一个方向的多变量表型，包含了中等数量的遗传方差。总之，这些数据表明，在可塑性是适应性的，选择遗传变异的最初塑料反应可以促进适应。然而，大环境对遗传变异的影响可能会降低适应潜力的新环境。
Adaptive plasticity allows populations to cope with environmental variation but is expected to fail as conditions become unfamiliar. In novel conditions, populations may instead rely on rapid adaptation to increase fitness and avoid extinction. Adaptation should be fastest when both plasticity and selection occur in directions of the multivariate phenotype that contain abundant genetic variation. However, tests of this prediction from field experiments are rare. Here, we quantify how additive genetic variance in a multivariate phenotype changes across an elevational gradient, and test whether plasticity and selection align with genetic variation. We do so using two closely related, but ecologically distinct, sister species of Sicilian daisy (Senecio, Asteraceae) adapted to high and low elevations on Mt. Etna. Using a quantitative genetic breeding design, we generated and then reciprocally planted c. 19,000 seeds of both species, across an elevational gradient spanning each species’ native elevation, and then quantified mortality and five leaf traits of emergent seedlings. We found that genetic variance in leaf traits changed more across elevations than between species. The high-elevation species at novel lower elevations showed changes in the distribution of genetic variance among the leaf traits, which reduced the amount of genetic variance in the directions of selection and the native phenotype. By contrast, the low-elevation species mainly showed changes in the amount of genetic variance at the novel high elevation, and genetic variance was concentrated in the direction of the native phenotype. For both species, leaf trait plasticity across elevations was in a direction of the multivariate phenotype that contained a moderate amount of genetic variance. Together, these data suggest that where plasticity is adaptive, selection on genetic variance for an initially plastic response could promote adaptation. However, large environmental effects on genetic variance are likely to reduce adaptive potential in novel environments.