Department of Evolution and Systematics, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Institute of Botany, Bratislava, Slovakia.
Department of Botany, Charles University, Prague, Czech Republic.
Syst Biol. 2023 Jun 17;72(3):491-504. doi: 10.1093/sysbio/syac071.
Hybridization is a key mechanism involved in lineage diversification and speciation, especially in ecosystems that experienced repeated environmental oscillations. Recently radiated plant groups, which have evolved in mountain ecosystems impacted by historical climate change provide an excellent model system for studying the impact of gene flow on speciation. We combined organellar (whole-plastome) and nuclear genomic data (RAD-seq) with a cytogenetic approach (rDNA FISH) to investigate the effects of hybridization and introgression on evolution and speciation in the genus Soldanella (snowbells, Primulaceae). Pervasive introgression has already occurred among ancestral lineages of snowbells and has persisted throughout the entire evolutionary history of the genus, regardless of the ecology, cytotype, or distribution range size of the affected species. The highest extent of introgression has been detected in the Carpathian species, which is also reflected in their extensive karyotype variation. Introgression occurred even between species with dysploid and euploid cytotypes, which were considered to be reproductively isolated. The magnitude of introgression detected in snowbells is unprecedented in other mountain genera of the European Alpine System investigated hitherto. Our study stresses the prominent evolutionary role of hybridization in facilitating speciation and diversification on the one hand, but also enriching previously isolated genetic pools. [chloroplast capture; diversification; dysploidy; European Alpine system; introgression; nuclear-cytoplasmic discordance; ribosomal DNA.].
杂交是谱系多样化和物种形成的关键机制，特别是在经历了反复环境波动的生态系统中。最近辐射的植物群体，在受历史气候变化影响的山地生态系统中进化，为研究基因流对物种形成的影响提供了一个极好的模型系统。我们结合细胞器（全质体）和核基因组数据（RAD-seq）以及细胞遗传学方法（rDNA FISH），研究了杂交和渐渗对 Soldanella 属（雪花莲，报春花科）进化和物种形成的影响。在雪花莲的祖先谱系中已经发生了普遍的渐渗，并且在该属的整个进化历史中一直持续存在，无论受影响物种的生态、细胞型或分布范围大小如何。在喀尔巴阡山脉物种中检测到的渐渗程度最高，这也反映在它们广泛的染色体变异中。甚至在具有非整倍体和整倍体细胞型的物种之间也发生了渐渗，这些物种被认为是生殖隔离的。在迄今研究的欧洲阿尔卑斯山系统的其他山地属中，雪花莲中检测到的渐渗程度是前所未有的。我们的研究一方面强调了杂交在促进物种形成和多样化方面的突出进化作用，但另一方面也丰富了以前隔离的遗传库。[叶绿体捕获；多样化；非整倍性；欧洲阿尔卑斯系统；渐渗；核质不和谐；核糖体 DNA。]
