Zou Peishan, Ng Wei Lun, Wu Wei, Dai Seping, Ning Zulin, Wang Shuqiong, Liu Ying, Fan Qiang, Zhou Renchao
State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China.
Guangzhou Institute of Forestry and Landscape ArchitectureGuangzhou, China.
Front Plant Sci. 2017 Apr 26;8:673. doi: 10.3389/fpls.2017.00673. eCollection 2017.
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 , which are morphologically similar to a natural hybrid, , by sequencing a chloroplast intergenic spacer, nuclear ribosomal internal transcribed spacer and two low-copy nuclear genes ( and ) 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 and , and the other between and . The origins of these hybrids are therefore clearly different from , and morphological similarity for the three hybrids is most likely due to their origins from hybridization between the same creeping species and a different erect species in each of the three cases. We also observed low rate of introgression from to , and genetic exchange between them may transfer adaptive traits to . 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.
仅基于形态学来推断杂交类群的起源是困难的，因为形态相似的杂种可能源自同一亲本物种不同种群之间的杂交，或者由不同亲本物种杂交产生。在本研究中，我们通过对这些类群及其假定亲本物种的叶绿体基因间隔区、核糖体核糖体内转录间隔区以及两个低拷贝核基因（和）进行测序，研究了中的两个半匍匐类群的起源，这两个类群在形态上与一个天然杂种相似。我们的序列分析为这两个半匍匐类群的杂种状态提供了有力证据：一个起源于和之间的杂交，另一个起源于和之间的杂交。因此，这些杂种的起源明显不同于，这三个杂种的形态相似性很可能是由于它们均起源于同一个匍匐物种与不同直立物种在三种情况下各自的杂交。我们还观察到从到的渐渗率较低，它们之间的基因交换可能会将适应性性状转移到。这两个杂种罕见的出现可能是由于一种情况下亲本物种之间的范围重叠较小，以及另一种情况下亲本物种之间的花期不同。
