Chromosomal stasis in diploids contrasts with genome restructuring in auto‐ and allopolyploid taxa ofHepatica(Ranunculaceae)

Abstract

Summary• Polyploidization and chromosomal rearrangements are recognized as major forces in plant evolution. Their role is investigated in the disjunctly distributed northern hemisphere Hepatica (Ranunculaceae).• Chromosome numbers, karyotype morphology, banding patterns, 5S and 35S rDNA localization in all known species were investigated and interpreted in a phylogenetic context established from nuclear internal transcribed spacer (ITS) and plastid matK sequences.• All species had a chromosome base number of x = 7. The karyotype was symmetric and showed little variation among diploids with one locus each of 5S and 35S rDNA, except for interpopulational variation concerning 35S rDNA loci number and localization in H. asiatica. Tetraploids exhibited chromosomal changes, including asymmetry and/or loss of rDNA loci. Nuclear and plastid sequences resulted in incongruent topologies because of the positions of some tetraploid taxa. The diversification of Hepatica occurred not earlier than the Pliocene.• Genome restructuring, especially involving 35S rDNA, within a few million yr or less characterizes evolution of both auto-and allopolyploids and of the diploid species H. asiatica, which is the presumptive ancestor of two other diploid species.

Morphological characterization under different ecological habitats and physical mapping of 5S and 45S rDNA in Lilium distichum with fluorescence in situ hybridization

“…Size bars = 10 μm. consist of tandem repeats, which proved to be efficient markers for in situ hybridization because they have the ability to conserve the DNA sequences present in high copy numbers, permitting the application of cloned heterologous probes (Lim et al 2005;Weiss-Schneeweiss et al 2007;Hwang et al 2015). Present FISH results showed considerable variations in the size, number, and position of 45S rDNA and 5S loci in L. distichum that cater effective molecular markers to identify karyotype structure variations associated with plant evolution and speciation (Hwang et al 2011).…”

Chromosome numbers of 28 taxa in 10 genera of the Ranunculaceae (buttercup family) from the Korean peninsula

“…In Korea, about 104 species of 20 genera in the buttercup family have been recognized, which makes the family the third largest Eudicot family in Korea (Park 2007;Kim et al 2008). For its ornamental and medicinal value, the family is economically very important in Asia (Tamura 1993;Cai et al 2010 (Bae 2000;Cai et al 2009).…”

“…(buttercup family), one of early lineages in flowering plants, is characterized by hypogynous flowers with numerous stamens, and approximately 2500 species of 59 genera occur mainly in temperate and cold temperate regions of the northern hemisphere, with the greatest species diversity in Asia (Tamura 1993;Takhtajan 1997;Wang et al 2001;Simpson 2006;Park 2007). Traditionally, the family has been divided into several tribes with or without subfamilies based on morphological, anatomical, and cytological characters.…”

“…Megaleranthis Ohwi is a monotypic, endemic genus to Korea, and two species of Hepatica Mill. occur restrictedly in the Korean peninsula: H. insularis Nakai in southern parts of the peninsula and H. maxima (Nakai) Nakai on Island Ulleng-do in the East Sea (Oh et al 2005;Park 2007).…”

“…For its ornamental and medicinal value, the family is economically very important in Asia (Tamura 1993;Cai et al 2010 (Bae 2000;Cai et al 2009). In addition, about 20 species are endemic to Korea (Oh et al 2005;Park 2007). Megaleranthis Ohwi is a monotypic, endemic genus to Korea, and two species of Hepatica Mill.…”