Melichárková Andrea, Šlenker Marek, Zozomová-Lihová Judita, Skokanová Katarína, Šingliarová Barbora, Kačmárová Tatiana, Caboňová Michaela, Kempa Matúš, Šrámková Gabriela, Mandáková Terezie, Lysák Martin A, Svitok Marek, Mártonfiová Lenka, Marhold Karol
Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovakia.
Department of Botany, Faculty of Science, Charles University, Prague, Czechia.
Front Plant Sci. 2020 Dec 18;11:588856. doi: 10.3389/fpls.2020.588856. eCollection 2020.
Recurrent polyploid formation and weak reproductive barriers between independent polyploid lineages generate intricate species complexes with high diversity and reticulate evolutionary history. Uncovering the evolutionary processes that formed their present-day cytotypic and genetic structure is a challenging task. We studied the species complex of , composed of diploid endemics in the European Mediterranean and diploid-polyploid lineages more widely distributed across Europe, focusing on the poorly understood variation in Central Europe. To elucidate the evolution of Central European populations we analyzed ploidy level and genome size variation, genetic patterns inferred from microsatellite markers and target enrichment of low-copy nuclear genes (Hyb-Seq), and environmental niche differentiation. We observed almost continuous variation in chromosome numbers and genome size in s.str., which is caused by the co-occurrence of euploid and dysploid cytotypes, along with aneuploids, and is likely accompanied by inter-cytotype mating. We inferred that the polyploid cytotypes of s.str. are both of single and multiple, spatially and temporally recurrent origins. The tetraploid evolved at least twice in different regions by autopolyploidy from diploid . The extensive genome size and genetic variation of reflects differentiation induced by the geographic isolation of disjunct populations, establishment of triploids of different origins, and hybridization with sympatric . . Geographically structured genetic lineages identified in the species under study, which are also ecologically divergent, are interpreted as descendants from different source populations in multiple glacial refugia. The postglacial range expansion was accompanied by substantial genetic admixture between the lineages of . s.str., which is reflected by diffuse borders in their contact zones. In conclusion, we identified an interplay of diverse processes that have driven the evolution of the species studied, including allopatric and ecological divergence, hybridization, multiple polyploid origins, and genetic reshuffling caused by Pleistocene climate-induced range dynamics.
反复出现的多倍体形成以及独立多倍体系之间较弱的生殖隔离产生了具有高度多样性和网状进化历史的复杂物种复合体。揭示形成其现今细胞型和遗传结构的进化过程是一项具有挑战性的任务。我们研究了[物种名称]的物种复合体，其由欧洲地中海地区的二倍体特有种以及在欧洲分布更广的二倍体 - 多倍体系组成，重点关注中欧地区了解较少的变异情况。为了阐明中欧种群的进化，我们分析了倍性水平和基因组大小变异、从微卫星标记推断的遗传模式以及低拷贝核基因的靶向富集（Hyb - Seq），还有环境生态位分化。我们观察到狭义[物种名称]的染色体数目和基因组大小几乎连续变化，这是由整倍体和非整倍体细胞型以及非整倍体的共同出现所导致的，并且可能伴随着细胞型间的交配。我们推断狭义[物种名称]的多倍体细胞型具有单一和多个、在空间和时间上反复出现的起源。四倍体[物种名称]至少在不同区域通过二倍体[物种名称]的自体多倍体化进化了两次。[物种名称]广泛的基因组大小和遗传变异反映了间断种群的地理隔离、不同起源的三倍体的形成以及与同域[物种名称]的杂交所导致的分化。在该研究物种中鉴定出的地理结构遗传谱系，它们在生态上也存在差异，被解释为多个冰川避难所中不同源种群的后代。冰期后的范围扩张伴随着狭义[物种名称]谱系之间大量的基因混合，这在它们的接触区域表现为模糊的边界。总之，我们确定了多种过程的相互作用，这些过程推动了所研究物种的进化，包括异域和生态分化、杂交、多个多倍体起源以及更新世气候引起的范围动态所导致的基因重排。
