Federal Scientific Centre of the East Asia Terrestrial Biodiversity, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok, Russia.
Institute of General and Experimental Biology, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Russia.
Genetica. 2021 Apr;149(2):89-101. doi: 10.1007/s10709-021-00115-9. Epub 2021 Mar 12.
The genetic diversity and phylogenetic relationships of Oxytropis caespitosa, O. grandiflora, O. eriocarpa, O. mixotriche, O. nitens, O. peschkovae and O. triphylla, section Xerobia subgenus Oxytropis, in one of the main speciation centres of the genus Oxytropis (Baikal Siberia and adjacent territories of Northeastern Mongolia) were studied based on sequence analysis of the psbA-trnH, trnL-trnF and trnS-trnG intergenic spacers of cpDNA, as well as the ITS nrDNA. Most populations are characterized by a high level of chloroplast genetic diversity (h varied from 0.327 to 1.000 and π from 0.0001 to 0.0090) due to the ancient origin for some species and to hybridization and polyploidy for others. 67 haplotypes were identified, of which six were shared. Phylogenetic relationships among species could not be satisfactorily resolved. Only the haplotypes of O. triphylla formed a group with rather high support. Probably, O. caespitosa, O. grandiflora, O. mixotriche and O. nitens constitute a single genetic complex. As regards the ITS nrDNA polymorphism, we detected only two ribotypes (RX1, RX2). Both were found in O. caespitosa, O. eriocarpa, O. mixotriche and O. peschkovae, while RX1 was present in O. nitens and O. triphylla, RX2 in O. grandiflora. The absence of diagnostic species-specific variants for the markers studied, together with the sharing of cpDNA haplotypes and nrDNA ribotypes between species, and the resulting polytomies on the phylogenetic trees, confirm the hypothesis on the hybrid origin of some of them. Obviously, the reproductive barriers within the sect. Xerobia are weak. However, morphological differences between the species of the sect. Xerobia are clearly pronounced, even when they grow in sympatry.
在贝加尔湖西伯利亚和毗邻的蒙古国东北部地区这一主要的紫堇属（Oxytropis）物种形成中心之一，对紫堇属 Xerobia 亚属的 Oxytropis caespitosa、O. grandiflora、O. eriocarpa、O. mixotriche、O. nitens、O. peschkovae 和 O. triphylla 进行了 cpDNA 的 psbA-trnH、trnL-trnF 和 trnS-trnG 基因间隔区以及 ITS nrDNA 序列分析，以研究其遗传多样性和系统发育关系。大多数种群的叶绿体遗传多样性水平较高（h 值从 0.327 到 1.000，π值从 0.0001 到 0.0090），这是由于一些物种的古老起源以及其他物种的杂交和多倍体化所致。鉴定出 67 种单倍型，其中 6 种是共有单倍型。物种间的系统发育关系无法得到令人满意的解决。只有 O. triphylla 的单倍型形成了一个具有相当高支持率的群体。可能 O. caespitosa、O. grandiflora、O. mixotriche 和 O. nitens 构成了一个单一的遗传复合体。至于 ITS nrDNA 多态性，我们只检测到两种核糖体类型（RX1、RX2）。这两种核糖体类型都存在于 O. caespitosa、O. eriocarpa、O. mixotriche 和 O. peschkovae 中，而 RX1 存在于 O. nitens 和 O. triphylla 中，RX2 存在于 O. grandiflora 中。在所研究的标记物中没有发现具有诊断意义的种特异性变异，同时 cpDNA 单倍型和 nrDNA 核糖体类型在物种间共享，以及系统发育树上的多分支，证实了它们中的一些是杂交起源的假说。显然，Xerobia 亚属内的生殖隔离是薄弱的。然而，Xerobia 亚属的物种之间的形态差异非常明显，即使它们在同域生长时也是如此。
