The coincidence of ecological opportunity with hybridization explains rapid adaptive radiation in Lake Mweru cichlid fishes
The coincidence of ecological opportunity with hybridization explains rapid adaptive radiation in Lake Mweru cichlid fishes
复制标题
DOI：
10.1038/s41467-019-13278-z
复制
发表时间：
2019-12-03
影响因子：
16.6
通讯作者：
Seehausen, Ole
中科院分区：
文献类型：
--
作者：
Meier, Joana, I;Stelkens, Rike B.;Seehausen, Ole
适应性辐射的过程被经典地假设为需要将谱系与其来源（无基因流）和相关物种（无竞争）隔离。或者，物种之间的杂交可能会产生有利于适应性辐射的遗传变异。在这里，我们研究了两个非洲大湖的单倍色慈鲷组合来检验这些假设。更大的生物隔离（更少的谱系）预示着班韦乌鲁湖的竞争限制更少，因此有更多的生态机会，而杂交的机会预示着姆韦鲁湖的遗传潜力增加。在班韦乌鲁湖，我们没有发现杂交的证据，也没有发现适应性辐射。我们表明，班韦乌鲁谱系也在姆韦鲁湖定居，在那里他们与刚果谱系杂交，然后经历了在生态和形态上惊人互补的多重适应性辐射。我们的数据表明，几个相关谱系的存在并不一定会阻止适应性辐射，尽管它限制了形态多样化的轨迹。相反，当杂交产生遗传变异时，它可能会促进适应性辐射，否则辐射可能会晚得多、进展得更慢或永远不会发生。
The process of adaptive radiation was classically hypothesized to require isolation of a lineage from its source (no gene flow) and from related species (no competition). Alternatively, hybridization between species may generate genetic variation that facilitates adaptive radiation. Here we study haplochromine cichlid assemblages in two African Great Lakes to test these hypotheses. Greater biotic isolation (fewer lineages) predicts fewer constraints by competition and hence more ecological opportunity in Lake Bangweulu, whereas opportunity for hybridization predicts increased genetic potential in Lake Mweru. In Lake Bangweulu, we find no evidence for hybridization but also no adaptive radiation. We show that the Bangweulu lineages also colonized Lake Mweru, where they hybridized with Congolese lineages and then underwent multiple adaptive radiations that are strikingly complementary in ecology and morphology. Our data suggest that the presence of several related lineages does not necessarily prevent adaptive radiation, although it constrains the trajectories of morphological diversification. It might instead facilitate adaptive radiation when hybridization generates genetic variation, without which radiation may start much later, progress more slowly or never occur.