Karyotype evolution supports the molecular phylogeny in the genus Ranunculus (Ranunculaceae)
Karyotype evolution supports the molecular phylogeny in the genus Ranunculus (Ranunculaceae)
复制标题
DOI：
10.1016/j.ppees.2015.11.001
复制
发表时间：
2016-02-01
影响因子：
3.6
通讯作者：
Hoerandl, Elvira
中科院分区：
文献类型：
--
作者：
Baltisberger, Matthias;Hoerandl, Elvira
染色体的形态特征可以根据着丝粒的位置来重建核型进化。不同的核型往往反映了物种形成的事件，因为它们可以建立物种之间的交叉障碍。因此，核型的进化往往与被子植物属内的分支分裂和分化相一致。在这里，我们研究了大世界性属毛茛和相关属的核型进化，以检验核型与主要分支一致的假设。我们调查了36个物种的有丝分裂的核型，另外87个物种的文献记录进行了评估，并通过将核型映射到已发表的分子系统发育树上来重建祖先状态。共有10种核型可以作为特征状态进行区分，8种基于基数x=8，2种基于基数x=7。毛茛属内的祖先类型具有4条中部着丝粒染色体和4条亚中部着丝粒/亚端部着丝粒染色体的特征，并在毛茛属的5个主要基部分支中占优势。subg. Auricomus）和四个相关属（Coptidium、Halerpestes、Kumlienia和Trautvetteria）。另外四种核型是毛茛属内两个主要分支的祖先和优势种。subg.毛茛），而另外三个只发生在毛茛属植物的顶生枝上。在相关属中，无花果属和角头亚目也显示出衍生的核型。因此，核型形态学支持基于分子和形态学数据的属和亚属分类。核型进化通常驱动具有不对称臂的染色体数目增加，并且从x = 8减少到x=7。同域物种种间同倍体杂交和杂交实验的综述表明，具有相同核型的物种的可杂交性增强，具有不同核型的物种之间的杂交障碍较强。我们的结论是核型进化是毛茛属内的物种形成和分支分化的主要驱动力。(C)2015作者由爱思唯尔有限公司出版。代表瑞士联邦地理植物研究所，鲁贝尔基金会。
Karyotype evolution can be reconstructed by the characterization of chromosome morphology, based on the position of centromeres. Different karyotypes often reflect speciation events within phylogenies as they can establish crossing barriers between species. Hence, evolution of karyotypes often is congruent with splits and differentiation of clades within phylogenies of angiosperm genera. Here we study karyotype evolution in the big cosmopolitan genus Ranunculus and in related genera to test the hypothesis that karyotypes are congruent with major clades. We investigated karyotypes on mitoses of 36 species, evaluated literature records for additional 87 species, and reconstructed ancestral states by mapping karyotypes onto a published molecular phylogenetic tree. Altogether ten karyotypes can be discriminated as character states, eight based on the base number x=8, and two on the base number x=7. The ancestral type within Ranunculus is characterized by four metacentric and four submetacentric/subtelocentric chromosomes, and dominates in five major basal clades of Ranunculus (R. subg. Auricomus) and in four of the related genera (Coptidium, Halerpestes, Kumlienia, and Trautvetteria). Another four karyotypes are ancestral and predominant in two major clades within Ranunculus (R. subg. Ranunculus), while three further ones occur only on terminal branches of the buttercup phylogeny. Among related genera, Ficaria and Ceratocephala also show derived karyotypes. Karyotype morphology thus supports generic and infra generic classifications based on molecular and morphological data. Karyotype evolution drives in general to increasing number of chromosomes with asymmetric arms, and to a reduction from x = 8 to x=7 chromosomes. A review of interspecific homoploid hybridization in sympatric species, and of crossing experiments suggests enhanced crossability of species with the same karyotype and strong crossing barriers between those with different karyotypes. We conclude that karyotype evolution is a major driver of speciation and differentiation of clades within Ranunculus. (C) 2015 The Authors. Published by Elsevier GmbH. on behalf of Geobotanisches Institut ETH, Stiftung Ruebel.