Maintenance of species boundaries in three sympatric Ligularia(Senecioneae,Asteraceae)species  

作　　者：Ningning Zhang Yongpeng Ma Ryan A.Folk Jiaojun Yu Yuezhi Pan Xun Gong 

机构地区：[1]Key Laboratory for Plant Diversity and Biogeography of East Asia,Kunming Institute of Botany,the Chinese Academy of Sciences,Kunming 650201,China [2]University of the Chinese Academy of Sciences,Beijing 100049,China [3]Florida Museum of Natural History,University of Florida,Gainesville,FL 32611,USA

出　　处：《Journal of Integrative Plant Biology》2018年第10期986-999,共14页植物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.31470336 to X.G.and 31600178 to J.Y.)

摘　　要：The key process in speciation concerns the formation and maintenance of reproductive isolating barriers between diverging lineages. Although species boundaries are frequently investigated between two species across many taxa, reproductive isolating barriers among multiple species （：〉2） that would represent the most common phenomenon in nature, remain to be clarified. Here, we use double digest restriction-site associated DNA （ddRAD） sequencing to examine patterns of hybridization at a sympatric site where three Ligularia species grow together and verify whether those patterns contribute to the maintenance of boundaries among species. The results based on the RAD SNP datasets indicated hybridization Ligularia cyathiceps x L. duciformis and L. duciformis x L. yunnanensis were both restricted toFls plus a few first-generation backcrosses and no gene introgression were identified, giving rise to strong reproductive isolation among hybridizing species. More- over, hybrid swarm simulation, using HYBRIDLAB, indicated the RAD SNP datasets had sufficient discriminatory power for accurate hybrid detection. We conclude that parental species show strong reproductive isolation and they still maintain species boundaries, which may be the key mechanism to maintain species diversity of Ligualria in the eastern Qinghai-Tibetan Plateau and adjacent areas. Moreover, this study highlights the effectiveness of RAD sequencing in hybridization studies.The key process in speciation concerns the formation and maintenance of reproductive isolating barriers between diverging lineages. Although species boundaries are frequently investigated between two species across many taxa, reproductive isolating barriers among multiple species （：〉2） that would represent the most common phenomenon in nature, remain to be clarified. Here, we use double digest restriction-site associated DNA （ddRAD） sequencing to examine patterns of hybridization at a sympatric site where three Ligularia species grow together and verify whether those patterns contribute to the maintenance of boundaries among species. The results based on the RAD SNP datasets indicated hybridization Ligularia cyathiceps x L. duciformis and L. duciformis x L. yunnanensis were both restricted toFls plus a few first-generation backcrosses and no gene introgression were identified, giving rise to strong reproductive isolation among hybridizing species. More- over, hybrid swarm simulation, using HYBRIDLAB, indicated the RAD SNP datasets had sufficient discriminatory power for accurate hybrid detection. We conclude that parental species show strong reproductive isolation and they still maintain species boundaries, which may be the key mechanism to maintain species diversity of Ligualria in the eastern Qinghai-Tibetan Plateau and adjacent areas. Moreover, this study highlights the effectiveness of RAD sequencing in hybridization studies.

关 键 词：Maintenance of species boundaries in three sympatric Ligularia SENECIONEAE Asteraceae)species 

分 类 号：Q943[生物学—植物学]