Tight species cohesion among sympatric insular wild gingers (Asarum spp. Aristolochiaceae) on continental islands: Highly differentiated floral characteristics versus undifferentiated genotypes

PLoS One

Yoshiyuki Maeda¹  Hiroaki Setoguchi²  Junshi Matsuda²  Junichi Nagasawa³ 

[1] Faculty of Science, Kagoshima University, Kagoshima, Japan;Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Sakyo-ku, Kyoto, Japan;Kyoto Botanical Garden, Shimokamo Hangi-cho, Sakyo-ku, Kyoto, Japan

关键词: Islands;    Population genetics;    Genetic loci;    Inbreeding;    Phylogenetic analysis;    Species diversity;    Flowers;    Phylogeography;   

DOI  :  10.1371/journal.pone.0173489

学科分类：医学（综合）

来源: Public Library of Science

【 摘 要 】

The Amami Island group of the Ryukyu Archipelago, Japan, harbors extensive species diversity of Asarum in a small landmass. The fine-scale population genetic structure and diversity of nine insular endemic Asarum species were examined using nuclear DNA microsatellite loci and ITS sequences. High population genetic diversity (HS = 0.45–0.79) was estimated based on the microsatellites, implying outcrossing of Asarum species within populations accompanied by inbreeding. Bayesian clustering analyses revealed that species were divided into three robust genetic clusters and that the species within each cluster had a homogeneous genetic structure, indicating incomplete lineage sorting. This conclusion was supported by an ITS phylogeny. The degree of genetic differentiation among species was very low both within and between clusters (FST = 0.096–0.193, and 0.096–0.266, respectively). Although species can be crossed artificially to produce fertile hybrids, our results indicate that there is very little evidence of hybridization or introgression occurring among species in the wild, even within stands composed of multiple sympatric species. The highly differentiated floral morphology of the studied species is likely to impose reproductive isolation between them and maintain their integrity in the wild. A lack of genetic differentiation between sympatric species suggests that speciation within this group occurred rapidly and recently.

【 授权许可】

CC BY