Detecting east–west genetic differentiation in Castanopsis (Fagaceae) on the main islands of Japan and north–south on the Ryukyu Islands, based on chloroplast haplotypes

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• 作者：Kyoko Aoki ; Saneyoshi Ueno ; Takashi Kamijo…
• 关键词：Broadleaved evergreen forests ; Castanopsis ; Chloroplast ; Glacial refugia ; Microsatellite ; Phylogeography
• 刊名：Plant Systematics and Evolution
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：302
• 期：8
• 页码：1093-1107
• 全文大小：1,224 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Sciences
  Plant Ecology
  Plant Anatomy and Development
  Plant Systematics/Taxonomy/ Biogeography
  
• 出版者：Springer Wien
• ISSN：1615-6110
• 卷排序：302

文摘

Castanopsis (Fagaceae) is a plant genus that includes dominant tree species in the broadleaved evergreen forests of Japan. In this study, we investigated the genetic diversity and genetic structure of 76 natural populations of C. sieboldii and C. cuspidata, using variations in chloroplast DNA (cpDNA) sequences and chloroplast microsatellites (cpSSR) to elucidate the phylogeographic patterns reflected by seed flow. Most chloroplast haplotypes were shared between the two species on the main islands, although biparentally inherited microsatellite (nSSR) analyses showed a species-specific pattern in the previous study. The current patterns of haplotype sharing of cpDNA suggest the retention of an ancestral polymorphism that existed in Castanopsis before the two species split or historical introgression in the refugia during the glacial periods. Haplotype network was defined by three groups: Taiwan, southern parts of the Ryukyu Islands, and the central parts of the Ryukyu Islands to the main islands. The observed north–south genetic differentiation in cpDNA on the Ryukyu Islands was not detected by previous nSSR analyses. These results suggest that the lower levels of seed-mediated gene flow between the islands resulted in clear genetic differentiation of cpDNA on the Ryukyu Islands. Moreover, the cpSSR analysis indicated east–west genetic differentiation on the main islands, a pattern found in previous nSSR analyses of Castanopsis and several plant and animal species inhabiting Castanopsis forests in Japan, suggesting the existence of eastern refugia in the last glacial period. Our cpSSR investigation and their higher intraspecific variation provide a useful phylogeographic tool for these species.