The genetic basis of floral mechanical isolation between two hummingbird‐pollinated Neotropical understorey herbs
The genetic basis of floral mechanical isolation between two hummingbird‐pollinated Neotropical understorey herbs
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DOI：
10.1111/mec.16165
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发表时间：
2021-09
影响因子：
4.9
通讯作者：
Kathleen M. Kay;Y. Surget-Groba
中科院分区：
文献类型：
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作者：
Kathleen M. Kay;Y. Surget-Groba
花部分化是植物谱系间生殖隔离的重要因素，为研究物种形成的遗传学，包括数量性状基因座（QTL）的数量、效应大小、作用方式和互作等提供了机会。此外，花代表功能相关性状的套件，但目前还不清楚花的表型整合在多大程度上是由一个共享的遗传结构，这可能会促进或限制花性状的相关进化。在这里，我们研究了花形态特征的遗传结构，这些花的差异生殖隔离的两种蜂鸟授粉的新热带区下层草本植物之间的进化开关，从法案到前额花粉放置。对于大多数性状，我们发现多个QTL的相对较小的影响遍布整个基因组。我们还发现不同花性状相关的QTL效应的大量共定位和对齐，这些性状共同作用以促进异交并减少异源花粉转移。我们的研究结果与适应性多效性或许多共适应基因的连锁一致，其中任何一种都可以促进对相关选择的反应，并有助于在低水平杂交时稳定不同的表型。此外，我们的研究结果表明，花的机械隔离可以与适应的无穷小模型相一致。
Floral divergence can contribute to reproductive isolation among plant lineages, and thus provides an opportunity to study the genetics of speciation, including the number, effect size, mode of action and interactions of quantitative trait loci (QTL). Moreover, flowers represent suites of functionally interrelated traits, but it is unclear to what extent the phenotypic integration of the flower is underlain by a shared genetic architecture, which could facilitate or constrain correlated evolution of floral traits. Here, we examine the genetic architecture of floral morphological traits involved in an evolutionary switch from bill to forehead pollen placement between two species of hummingbird‐pollinated Neotropical understorey herbs that are reproductively isolated by these floral differences. For the majority of traits, we find multiple QTL of relatively small effect spread throughout the genome. We also find substantial colocalization and alignment of effects of QTL underlying different floral traits that function together to promote outcrossing and reduce heterospecific pollen transfer. Our results are consistent with adaptive pleiotropy or linkage of many co‐adapted genes, either of which could have facilitated a response to correlated selection and helped to stabilize divergent phenotypes in the face of low levels of hybridization. Moreover, our results indicate that floral mechanical isolation can be consistent with an infinitesimal model of adaptation.