J Syst Evol

• Research Articles •    

Genome-wide RAD sequencing data suggest predominant role of vicariance in Sino-Japanese disjunction of the monotypic genus Conandron (Gesneriaceae)

Shao‐Jun Ling1,2†, Xiao‐Lan Yao1,2†, Juli Caujapé‐Castells3, Jordi López‐Pujol4,5, Ke Tan1,2*, and Ming‐Xun Ren1,2*   

  1. 1 Ministry of Education Key Laboratory for Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants, Hainan University, Haikou 570228, China
    2 Center for Terrestrial Biodiversity of South China Sea, Hainan University, Haikou 570228, China
    3 The Jardín Botánico Canario “Viera y Clavijo”—UA CSIC (Cabildo de Gran Canaria), 35017 Las Palmas de Gran Canaria, Spain
    4 Botanic Institute of Barcelona (IBB), CSIC—Ajuntament de Barcelona, Barcelona 08038, Spain
    5 Escuela de Ciencias Ambientales, Universidad Espíritu Santo (UEES), Samborondón 091650, Ecuador

    These authors contributed equally to this study.
  • Received:2022-09-13 Accepted:2022-11-24 Online:2022-12-16


Disjunct distribution is a key issue in biogeography and ecology, but it is often difficult to determine the relative roles of dispersal vs. vicariance in disjunctions. We studied the phylogeographic pattern of the monotypic Conandron ramondioides (Gesneriaceae), which shows Sino-Japanese disjunctions, with ddRAD sequencing based on a comprehensive sampling of 11 populations from mainland China, Taiwan Island, and Japan. We found a very high degree of genetic differentiation among these three regions, with very limited gene flow and a clear Isolation by Distance pattern. Mainland China and Japan clades diverged first from a widespread ancestral population in the middle Miocene, followed by a later divergence between mainland China and Taiwan Island clades in the early Pliocene. Three current groups have survived in various glacial refugia during the Last Glacial Maximum, and experienced contraction and/or bottlenecks since their divergence during Quaternary glacial cycles, with strong niche divergence between mainland China + Japan and Taiwan Island ranges. Thus, we verified a predominant role of vicariance in the current disjunction of the monotypic genus Conandron. The sharp phylogenetic separation, ecological niche divergence among these three groups, and the great number of private alleles in all populations sampled indicated a considerable time of independent evolution, and suggests the need for a taxonomic survey to detect potentially overlooked taxa.

Key words: demography, ecological niche differences, isolation by distance, phylogeography, relict plant, species distribution model