PHENOTYPE-DEPENDENT NATIVE HABITAT PREFERENCE FACILITATES DIVERGENCE BETWEEN PARAPATRIC LAKE AND STREAM STICKLEBACK
PHENOTYPE-DEPENDENT NATIVE HABITAT PREFERENCE FACILITATES DIVERGENCE BETWEEN PARAPATRIC LAKE AND STREAM STICKLEBACK
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DOI：
10.1111/j.1558-5646.2009.00699.x
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发表时间：
2009-08-01
期刊：
影响因子：
3.3
通讯作者：
Lau, On Lee
中科院分区：
文献类型：
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作者：
Bolnick, Daniel I.;Snowberg, Lisa K.;Lau, On Lee
相邻种群之间的适应性分化反映了分化选择的多样性效应和基因流动的潜在不确定性效应之间的平衡。在大多数迁移-选择平衡模型中，基因流被认为反映了个体固有的分散能力，而不考虑个体的表型与可用栖息地之间的匹配。然而，栖息地的偏好可以减少不同栖息地之间的扩散，从而减轻迁移负荷，促进适应性分化。我们测试了栖息地的偏好是否有助于适应性的分歧，在一个经典的例子，迁移选择平衡：parapatric湖和流人口的三刺棘鱼（Gasterosteus aculeatus）。使用标记-移植-再捕获实验的形态不同的parapatric人口，我们发现，90%的湖泊和溪流刺鱼返回到它们的原生栖息地，减少76%的栖息地之间的迁移。此外，我们发现，扩散到一个非原生栖息地是表型依赖。从形态上看，移入湖中的溪流鱼比返回溪流的溪流鱼更像湖泊（而进入溪流的湖泊鱼则匡威）。强烈的原生栖息地偏好记录在这里增加了人口之间的适应性分歧的程度2 - 5倍，相对于随机运动的预期。这些结果说明了潜在的重要性，适应性栖息地的选择在驾驶parapatric分歧。
Adaptive divergence between adjoining populations reflects a balance between the diversifying effect of divergent selection and the potentially homogenizing effect of gene flow. In most models of migration-selection balance, gene flow is assumed to reflect individuals' inherent capacity to disperse, without regard to the match between individuals' phenotypes and the available habitats. However, habitat preferences can reduce dispersal between contrasting habitats, thereby alleviating migration load and facilitating adaptive divergence. We tested whether habitat preferences contribute to adaptive divergence in a classic example of migration-selection balance: parapatric lake and stream populations of three-spine stickleback (Gasterosteus aculeatus). Using a mark-transplant-recapture experiment on morphologically divergent parapatric populations, we showed that 90% of lake and stream stickleback returned to their native habitat, reducing migration between habitats by 76%. Furthermore, we found that dispersal into a nonnative habitat was phenotype dependent. Stream fish moving into the lake were morphologically more lake-like than those returning to the stream (and the converse for lake fish entering the stream). The strong native habitat preference documented here increases the extent of adaptive divergence between populations two- to fivefold relative to expectations with random movement. These results illustrate the potential importance of adaptive habitat choice in driving parapatric divergence.