Gene Flow Results in High Genetic Similarity betweenSibiraea(Rosaceae) Species in the Qinghai-Tibetan Plateau.
Studying closely related species and divergent populations provides insight into the process of speciation. Previous studies showed that theSibiraeacomplex's evolutionary history on the Qinghai-Tibetan Plateau (QTP) was confusing and could not be distinguishable on the molecular level. In this study, the genetic structure and gene flow ofSibiraea laevigataandSibiraea angustataon the QTP was examined across 45 populations using 8 microsatellite loci. Microsatellites revealed high genetic diversity inSibiraeapopulations. Most of the variance was detected within populations (87.45%) rather than between species (4.39%). We found no significant correlations between genetic and geographical distances among populations. Bayesian cluster analysis grouped all individuals in the sympatric area ofSibiraeainto one cluster and other individuals ofS. angustatainto another. Divergence history analysis based on the approximate Bayesian computation method indicated that the populations ofS. angustataat the sympatric area derived from the admixture of the 2 species. The assignment test assigned all individuals to populations of their own species rather than its congeneric species. Consistently, intraspecies were detected rather than interspecies first-generation migrants. The bidirectional gene flow in long-term patterns between the 2 species was asymmetric, with more fromS. angustatatoS. laevigata. In conclusion, theSibiraeacomplex was distinguishable on the molecular level using microsatellite loci. We found that the high genetic similarity of the complex resulted from huge bidirectional gene flow, especially on the sympatric area where population admixtures occurred. This study sheds light on speciation with gene flow in the QTP.
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China; College of Life Science, Luoyang Normal UniversityLuoyang, China.
Peng-Cheng
PC
Fu
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, China.
Qing-Bo
QB
Gao
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, China.
Fa-Qi
FQ
Zhang
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, China.
Rui
R
Xing
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China; College of Life Science, University of Chinese Academy of SciencesBeijing, China.
Jiu-Li
JL
Wang
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of SciencesXining, China; College of Life Science, University of Chinese Academy of SciencesBeijing, China.
Hai-Rui
HR
Liu
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, China.
Shi-Long
SL
Chen
Qinghai-Tibetan Plateau; Sibiraea; gene flow; genetic divergence; microsatellite