2006 Fiscal Year Final Research Report Summary
Population genetic studies on characteristics of molecular evolution in conifers
| Project/Area Number |
16370101
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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 |
Evolutionary biology
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| Research Institution | KYUSHU UNIVERCITY |
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Principal Investigator |
TACHDA Hidenori Kyushu University, Faculty of Sciences, Professor, 大学院理学研究院, 教授 (70216985)
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| Co-Investigator(Kenkyū-buntansha) |
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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| Project Period (FY) |
2004 – 2006
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| Keywords | conifer / genetic diversity / population genetics / adaptive variation / natural selection / Cupressacea / disease resistance genes / protochlorophyllide oxidoreductase |
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| Research Abstract |
In order to elucidate general characteristics of molecular evolution in conifer paying special attention to their adaptive evolution, we investigated population structure and candidate genes of adaptation including disease resistance genes in a few tree species belonging to a confer family, Cupressacea. We found the followings : 1) By studying polymorphisms in Cryptomeria japonica and divergences between it and one of its close relatives, Taxocium distichum, at 12 nuclear loci, three candidate genes of adaptive evolution were identified. 2) By using CAPS and microstellite markers, the population structure of C. japonica was analyzed and weak genetic differentiation between two varieties (Omote-Ura sugi) was found. 3) At two out often loci, two subspecies of T. distichum were found to be differentiated and shown to be increasing in their sizes. 4) Multiple copies of a putative NBS-LRR type R gene were found in C. japonica and T. distichum. In C. japonica, the ratio of nonsynonymous to synonymous nucleotide diversities was about 3 indicating action of strong selection in this gene family. 5) Two out of three chloroplast genes encoding light- independent protochlorophyllide oxidoreductase in a genus Thuja were suggested to be on their ways to become pseudogenes based on their sequence divergence, expression and effects on phenotypes. 6) The pattern of linkage disequilibrium in populations experiencing periodic fragmentation and admixture was quantified by a model analysis and shown to be very different from that in random mating populations.
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