Low genetic diversity and local adaptive divergence of Dracaena cambodiana (Liliaceae) populations associated with historical population bottlenecks and natural selection: An endangered long-lived tree endemic to Hainan Island, China
文献类型： 外文期刊
作者： Zheng, D. -J. 1 ; Xie, L. -S. 1 ; Zhu, J. -H. 2 ; Zhang, Z. -L. 1 ;
作者机构： 1.Hainan Acad Agr Sci, Key Lab Crop Genet & Breeding Hainan Prov, Haikou 571100, Peoples R China
2.Chinese Acad Trop Agr Sci, Inst Trop Biosci & Biotechnol, Haikou, Peoples R China
关键词： Dracaena cambodiana;Genetic diversity;Historical population bottleneck;Local adaptive divergence;Natural selection;Population differentiation
期刊名称：PLANT BIOLOGY （ 影响因子：3.081； 五年影响因子：2.972 ）
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收录情况： SCI
摘要： Historical population bottlenecks and natural selection have important effects on the current genetic diversity and structure of long-lived trees. Dracaena cambodiana is an endangered, long-lived tree endemic to Hainan Island, China. Our field investigations showed that only 10 populations remain on Hainan Island and that almost all have been seriously isolated and grow in distinct habitats. A considerable amount of genetic variation at the species level, but little variation at the population level, and a high level of genetic differentiation among the populations with limited gene flow in D. cambodiana were detected using inter-simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) analyses. No significant correlation was found between genetic diversity and actual population size, as the genetic diversities were similar regardless of population size. The Mantel test revealed that there was no correlation between genetic and geographic distances among the 10 populations. The UPGMA, PCoA and Bayesian analyses showed that local adaptive divergence has occurred among the D. cambodiana populations, which was further supported by habitat-private fragments. We suggest that the current genetic diversity and population differentiation of D. cambodiana resulted from historical population bottlenecks and natural selection followed by historical isolation. However, the lack of natural regeneration of D. cambodiana indicates that former local adaptations with low genetic diversity may have been genetically weak and are unable to adapt to the current ecological environments.
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