Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia.
Genes (Basel). 2019 Jul 31;10(8):579. doi: 10.3390/genes10080579.
Many species occur across environmental gradients and it is expected that these species will exhibit some signals of adaptation as heterogeneous environments and localized gene flow may facilitate local adaptation. While riparian zones can cross climate gradients, many of which are being impacted by climate change, they also create microclimates for the vegetation, reducing environmental heterogeneity. Species with differing distributions in these environments provide an opportunity to investigate the importance of genetic connectivity in influencing signals of adaptation over relatively short geographical distance. Association analysis with genomic data was used to compare signals of selection to climate variables in two species that have differing distributions along a river traversing a climate gradient. Results demonstrate links between connectivity, standing genetic variation, and the development of signals of selection. In the restricted species, the combination of high gene flow in the middle and lower catchment and occurrence in a microclimate created along riverbanks likely mitigated the development of selection to most climatic variables. In contrast the more widely distributed species with low gene flow showed a stronger signal of selection. Together these results strengthen our knowledge of the drivers and scale of adaptation and reinforce the importance of connectivity across a landscape to maintain adaptive potential of plant species.
许多物种存在于环境梯度中，预计这些物种将表现出一些适应的信号，因为异质的环境和局部基因流可能促进局部适应。虽然河岸带可以跨越气候梯度，其中许多梯度正在受到气候变化的影响，但它们也为植被创造了小气候，减少了环境的异质性。在这些环境中分布不同的物种为研究遗传连通性在相对短距离的地理距离上影响适应信号的重要性提供了机会。利用基因组数据进行关联分析，比较了两种沿穿越气候梯度的河流分布不同的物种的选择信号与气候变量之间的关系。结果表明，连通性、遗传变异和选择信号的发展之间存在联系。在受限制的物种中，中低流域高基因流和沿河岸形成的小气候的结合可能减轻了对大多数气候变量的选择发展。相比之下，分布范围更广、基因流较低的物种表现出更强的选择信号。这些结果共同加强了我们对适应的驱动因素和规模的认识，并强调了在景观范围内保持植物物种适应潜力的连通性的重要性。
