Similar Morphologies but Different Origins: Hybrid Status of Two More Semi-creeping Taxa of Melastoma.
Similar Morphologies but Different Origins: Hybrid Status of Two More Semi-creeping Taxa of Melastoma.
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相似的形态但不同的起源：两种半匍匐的野牡丹类群的杂交状态
DOI：
10.3389/fpls.2017.00673
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发表时间：
2017
影响因子：
5.6
通讯作者：
Zhou R
中科院分区：
文献类型：
--
作者：
Zou P;Ng WL;Wu W;Dai S;Ning Z;Wang S;Liu Y;Fan Q;Zhou R
仅仅根据形态来推断杂交类群的起源是很困难的，因为形态上相似的杂种可以由同一亲本物种的不同种群之间的杂交产生，或者通过不同亲本物种的杂交产生。在本研究中，我们通过对这些类群及其假定亲本物种中的叶绿体基因间间隔区、核核糖体内转录间隔区和两个低拷贝核基因（tpi 和 cam）进行测序，研究了野牡丹中两个半匍匐类群的起源，它们在形态上与天然杂交种 M. intermedium 相似。我们的序列分析为两种半匍匐类群的杂交状态提供了令人信服的证据：一种起源于 M. dodecandrum 和 M. malabathricum 之间的杂交，另一种起源于 M. dodecandrum 和 M. Normale 之间的杂交。因此，这些杂交种的起源明显不同于 M. intermedium，并且这三个杂交种的形态相似性很可能是由于它们起源于同一匍匐物种 M. dodecandrum 与三种情况下不同直立物种之间的杂交。我们还观察到从 M. normale 到 M. dodecandrum 的基因渗入率较低，它们之间的遗传交换可能会将适应性特征转移给 M. dodecandrum。这两种杂交品种很少出现，可能是由于一种情况下亲本物种之间的小范围重叠，而另一种情况下亲本物种之间的开花期不同。
Inferring the origins of hybrid taxa based on morphology alone is difficult because morphologically similar hybrids can arise from hybridization between different populations of the same parental species or be produced by hybridization of different parental species. In this study, we investigated the origins of two semi-creeping taxa in Melastoma, which are morphologically similar to a natural hybrid, M. intermedium, by sequencing a chloroplast intergenic spacer, nuclear ribosomal internal transcribed spacer and two low-copy nuclear genes (tpi and cam) in these taxa and their putative parental species. Our sequence analysis provides compelling evidence for the hybrid status of the two semi-creeping taxa: one originating from hybridization between M. dodecandrum and M. malabathricum, and the other between M. dodecandrum and M. normale. The origins of these hybrids are therefore clearly different from M. intermedium, and morphological similarity for the three hybrids is most likely due to their origins from hybridization between the same creeping species M. dodecandrum and a different erect species in each of the three cases. We also observed low rate of introgression from M. normale to M. dodecandrum, and genetic exchange between them may transfer adaptive traits to M. dodecandrum. Rare occurrence of these two hybrids may be due to small range overlaps between parental species in one case, and different flowering periods between parental species in the other.