Interspecific hybridization can generate functional novelty in cichlid fish
Interspecific hybridization can generate functional novelty in cichlid fish
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DOI：
10.1098/rspb.2019.1621
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发表时间：
2019-10-23
影响因子：
4.7
通讯作者：
Seehausen, O.
中科院分区：
文献类型：
--
作者：
Selz, O. M.;Seehausen, O.
种间杂交在进化中的作用仍在争论中。种间杂交被认为有助于生态新颖性的进化，因此当生态机会出现在亲本物种生态位之外时，新的生态位的入侵和适应性辐射。另一方面，两个生态分化物种之间的杂交可能在各自的生态位上表现得不如亲本物种，因为杂交种在两个生态位上的表现都是中等的。因此，杂交的进化结果可能依赖于背景，这取决于除了亲本物种之外的生态机会是否存在。令人惊讶的是，这些互补的预测可能从未在相同的动物实验中得到验证。为此，我们调查了不同生态物种之间的杂交在取食父母双方都不适应的食物时是否表现得不如亲本物种，以及如果相同的杂交物种在取食没有一个物种适应的食物时表现得比双亲更好。我们创造了两个非洲慈鱼物种之间的第一代杂交后代。在摄食效率实验中，我们测量了杂交种和亲本物种在食物类型上的表现，这些食物类型既代表了亲本物种的生态位，也代表了额外的“新”生态位，这些食物类型没有被亲本物种中的任何一个所使用，而是被非洲慈鱼辐射中的其他物种所使用。我们发现，与亲本物种相比，杂交种对“新”食物类型的摄食效率更高，但对亲本食物类型的摄食效率通常较低。这表明，杂交可以产生与生态相关的功能变异，允许获得亲本物种生态位以外的资源。因此，我们支持种间杂交进化影响的生态环境依赖性假说。
The role of interspecific hybridization in evolution is still being debated. Interspecific hybridization has been suggested to facilitate the evolution of ecological novelty, and hence the invasion of new niches and adaptive radiation when ecological opportunity is present beyond the parental species niches. On the other hand, hybrids between two ecologically divergent species may perform less well than parental species in their respective niches because hybrids would be intermediate in performance in both niches. The evolutionary consequences of hybridization may hence be context-dependent, depending on whether ecological opportunities, beyond those of the parental species, do or do not exist. Surprisingly, these complementary predictions may never have been tested in the same experiment in animals. To do so, we investigate if hybrids between ecologically distinct cichlid species perform less well than the parental species when feeding on food either parent is adapted to, and if the same hybrids perform better than their parents when feeding on food none of the species are adapted to. We generated two first-generation hybrid crosses between species of African cichlids. In feeding efficiency experiments we measured the performance of hybrids and parental species on food types representing both parental species niches and additional 'novel' niches, not used by either of the parental species but by other species in the African cichlid radiations. We found that hybrids can have higher feeding efficiencies on the 'novel' food types but typically have lower efficiencies on parental food types when compared to parental species. This suggests that hybridization can generate functional variation that can be of ecological relevance allowing the access to resources outside of either parental species niche. Hence, we provide support for the hypothesis of ecological context-dependency of the evolutionary impact of interspecific hybridization.