Karyology of plant species endemic to Ullung Island (Korea) and selected relatives in peninsular Korea and Japan

Abstract

Chromosomal changes, including polyploidy and dysploidy, often accompany speciation of angiosperms in continental regions. In contrast, on geologically young oceanic islands, little change in chromosome number occurs during speciation of endemics. Absence of change in number of chromosomes does not necessarily mean lack of chromosomal rearrangements. To determine whether detailed karyotypic changes accompany speciation in island habitats, nine endemic species in Abelia, Acer, Campanula, Dystaenia, Hepatica, Rubus, Valeriana, Veronica and Viola of Ullung Island, a geologically young volcanic island off the coast of peninsular Korea in the Eastern Sea, have been compared with progenitors in mainland Korea and Japan. Results confirm that no changes in ploidy level or dysploidy have occurred during speciation of these endemic island taxa. Detailed karyotypic analysis indicates that most of the taxa have not undergone significant macromorphological chromosomal changes. In the bitypic genus Dystaenia (Umbelliferae), D. takesimana, endemic to Ullung Island, differs karyotypically from its progenitor, D. ibukiensis from Japan, in a number of chromosomal elements, some of which appear to be satellites and others of which may represent B chromosomes. This suggests that rDNA loci might have been lost or rearranged during speciation. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 138, 93–105.

Chromosome numbers in plant taxa endemic to the Balearic Islands

“…Both genera are apparently sisters in a ribosomal phylogeny of Apioideae drawn from ITS sequences (Downie et al, 2000). Accessory chromosomes have not been reported in any species of Apium so far analysed and have been rarely documented in Apiaceae (Moore, 1971; but see Weiss et al, 2002). Metaphase chromosomes of the Balearic subspecies are small (1.5-2.5 mm), showing mainly metacentric, submetacentric and some subtelocentric pairs.…”

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

“…As reported before (Weiss et al 2002;WeissSchneeweiss et al 2007), both are diploid, 2n = 14, with large R-type chromosomes (x = 7; Figures 16, 17). Hepatica comprises 11 taxa worldwide and reaches its highest diversity in northeastern Asia with five species and one variety.…”

“…nipponica Nakai was recorded (Kurita 1961), and four tetraploids were reported: H. henryi Steward, H. transsilvanica Fuss, H. nobilis var. pubescens (M. Hiroe) Kitam., and H. yamatutai Nakai (Weiss et al 2002;Weiss-Schneeweiss et al 2007). …”

Diferenciación cromosómica en tres especies de Leptostemonum (Solanum, Solanaceae) endémicos de islas oceánicas.

“…It is said that several factors may be working together to limit chromosomal changes during speciation in oceanic islands (Carr, 1998;Stuessy & Ono, 1998;Weiss et al, 2002). Low levels of genetic variation within island species may lower the probability of chromosomal alterations.…”