Genome-wide analysis confirms the independent origin of the Japanese and Korean Adonis amurensis (Ranunculaceae)

Abstract Adonis is a genus popularly known as ornamental plants called fukujusō , belonging to the Ranunculaceae, and distributed from Europe to West and Central Asia to East Asia. In Japan, four species are recognized, including diploid and tetraploid lineages. In the past decades, some genetic studies have raised questions about lineage boundaries, between Japan and Korea. In this study, we used genome-wide sequencing of a large sampling dataset of Japanese and Korean Adonis species to address phylogenetic relationships between species. We also compared samples according to their distribution, morphological traits, and chromosome numbers. As a result, we identified six phylogenetic lineages that can be distinguished as species, four of these distributed in Japan. Based on the molecular and morphological data, we suggest that specimens from Japan and Korea previously identified as A. amurensis belong to different lineages and should be treated as distinct species. We point out differences between those lineages and suggest a new combination of the name Adonis puberula to describe the Hokkaido (Japan) specimens. We obtained evidence suggesting that Japanese A. multiflora is a sister to A. shikokuensis , including both Japanese and Korean samples with morphological differences that can be explored in future studies. Finally, A. ramosa ( fukujusō ), the Japan endemic tetraploid species, showed great genetic and morphological variation, as previously reported by other studies.