2006 Fiscal Year Final Research Report Summary
Genetic conservation of rare coniferous natural forests in Japan
| Project/Area Number |
16380112
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林学・森林工学
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| Research Institution | Forestry and Forest Products Research Institute |
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Principal Investigator |
TSUMURA Yoshihiko Forestry and Forest Products Research Institute, Department of Forest Genetics, Laboratory Head, 森林遺伝研究領域, 室長 (20353774)
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| Co-Investigator(Kenkyū-buntansha) |
TANI Naoki Forestry and Forest Products Research Institute, Department of Forest Genetics, Senior Researcher, 森林遺伝研究領域, 主任研究員 (90343798)
MATSUMOTO Asako Forestry and Forest Products Research Institute, Department of Forest Genetics, Senior Researcher, 森林遺伝研究領域, 主任研究員 (90353862)
IHARA Tokuko Forestry and Forest Products Research Institute, Department of Forest Genetics, Senior Researcher, 森林遺伝研究領域, 主任研究員 (40353594)
TACHITA Hidenori Kyushu University, Department of Biology, Professor, 大学院理学研究院, 教授 (70216985)
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| Project Period (FY) |
2004 – 2006
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| Keywords | conifer / conservation / genome / population genetics / genetic structure / genetic diversity |
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| Research Abstract |
We investigated 25 natural populations of Chamaecyparis obtusa using 51 cleaved amplified polymorphic sequence (CAPS) markers, which were developed using information on sequence-tagged sites (STS) in Cryptomeria japonica. Most CAPS markers have codominant expression patterns, and are suitable for population studies because of their robustness and convenience. We estimated various genetic diversity parameters, including average heterozygosity (He) and allelic richness, and found that the more peripheral populations tended to have lower genetic diversity than central populations, in agreement with a previous theoretical study. The overall genetic differentiation between populations was low, but statistically significant (GST=0.039), and similar to the level reported in a previous allozyme study. We attempted to detect nonneutral loci associated with local adaptation to clarify the relationship between the fixation index (FST) and He-values for each locus, and found seven candidate nonneu
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tral loci. Phylogenetic tree analysis of the populations and Bayesian clustering analysis revealed a pattern of gradually increasing isolation of populations with increasing geographical distance. Three populations had a high degree of linkage disequilibrium, which we attribute to severe bottlenecks due to human disturbance or competition with other species during their migration from refugia after the most recent glaciation. We also discuss the importance of these natural populations of C.obtusa as a genetic resource.
We investigated 29 natural populations of Cryptomeria japonica using 148 cleaved amplified polymorphic sequence markers to elucidate their genetic structure and identify candidate adaptive genes of this species. In accordance with the inferred evolutionary history of the species during and after the last glacial episode, the genetic diversity was higher in western populations than in northern populations. The results of phylogenetic and genetic structure analyses suggest that populations of the two main varieties of the species have clearly diverged from each other, and that two of the examined loci are strongly associated with the differentiation between the two varieties. Using a coalescent simulation based on FST and He values, we detected five genes that had higher, and two that had lower, values than the respective 99 % confidence intervals (CIs) that are theoretically expected intervals under a neutral infinite-island model. We also detected 13 outlier loci using a coalescent simulation based on the assumption that the two varieties originated from the splitting of an ancestral population. Four of these loci were detected by both methods, two of which were detected in a genetic structure analysis as loci associated with differentiation, and are strong candidates for genes that have been subject to selection and, thus, contributed to the genetic differentiation between the two varieties of the species. Less
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Research Products
(6 results)
