VARIABLE PROGRESS TOWARD ECOLOGICAL SPECIATION IN PARAPATRY: STICKLEBACK ACROSS EIGHT LAKE-STREAM TRANSITIONS
VARIABLE PROGRESS TOWARD ECOLOGICAL SPECIATION IN PARAPATRY: STICKLEBACK ACROSS EIGHT LAKE-STREAM TRANSITIONS
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DOI：
10.1111/j.1558-5646.2009.00665.x
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发表时间：
2009-07-01
期刊：
影响因子：
3.3
通讯作者：
Hendry, Andrew P.
中科院分区：
文献类型：
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作者：
Berner, Daniel;Grandchamp, Anne-Catherine;Hendry, Andrew P.
在最初的高基因流面前，不同生境之间的分歧选择有时会驱动适应性分歧和生殖隔离的进化。沿着这条生态物种形成途径的“进展”可以从最小的分歧到完全的物种形成。我们研究这种变化的threespine棘鱼，独立地跨越8个湖流栖息地过渡演变。通过量化刺鱼的饮食，我们表明，湖流过渡通常与湖沼底栖生态交错带相吻合。通过测量基于遗传的表型，我们表明，这些生态交错区往往产生适应性分歧觅食形态。通过分析中性遗传标记（微卫星），我们发现，适应性分歧往往与存在两个群体保持至少部分生殖隔离parapatry。基于聚结的模拟进一步表明，这些人群已经分化的基因流在几千代，虽然我们不能排除阶段的异域分歧的可能性。最后，我们发现显着的变化之间的八个湖流过渡的进展，生态物种。这种变化使我们能够假设，进展一般是由强大的分歧选择和有限的分散在栖息地过渡。因此，我们的研究提出了一个案例，在一个parapatric环境中的生态物种形成，同时也突出了结果的变化。
Divergent selection between contrasting habitats can sometimes drive adaptive divergence and the evolution of reproductive isolation in the face of initially high gene flow. "Progress" along this ecological speciation pathway can range from minimal divergence to full speciation. We examine this variation for threespine stickleback fish that evolved independently across eight lake-stream habitat transitions. By quantifying stickleback diets, we show that lake-stream transitions usually coincide with limnetic-benthic ecotones. By measuring genetically based phenotypes, we show that these ecotones often generate adaptive divergence in foraging morphology. By analyzing neutral genetic markers (microsatellites), we show that adaptive divergence is often associated with the presence of two populations maintaining at least partial reproductive isolation in parapatry. Coalescent-based simulations further suggest that these populations have diverged with gene flow within a few thousand generations, although we cannot rule out the possibility of phases of allopatric divergence. Finally, we find striking variation among the eight lake-stream transitions in progress toward ecological speciation. This variation allows us to hypothesize that progress is generally promoted by strong divergent selection and limited dispersal across the habitat transitions. Our study thus makes a case for ecological speciation in a parapatric context, while also highlighting variation in the outcome.