| Project/Area Number |
05640779
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
系統・分類
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| Research Institution | Hirosaki University, Facalty of Science |
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Principal Investigator |
MATSUOKA Norimasa Hirosaki University Facuty of Seience, Associate Professor, 理学部, 助教授 (10125461)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | echinoderm / sea-urchin / starfish / evolution / allozyme variation / electrophoresis / genetic distance / molecalor phylogenetic tree / 分子系統学 / 電気泳動法 / アイソザイム変異 |
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| Research Abstract |
1.The family Asteriidae of the order Forcipulatida from Japanese waters includes the five common starfish species belonging to the five different genera. They are Asterias amurensis, Aphelasterias Japonica, Distolasterias nipon, Coscinasterias acutispina and Plazaster borealis. The phylogenetic relationship of these five members were investigated by electrophoretic analyzes of 15 different eazymes. From the allozyme variation observed in 31 genetic loci, the Nei's genetic distances between species were calculated and the molecular phylogenetic tree for the five species was constructed. the phylogenetic tree indicated the following : (1)The five species are phylogenetically divided into three clusters : (i)A.amurensis and P.borealis ; (ii)A.japonica and D.nipon ; and (iii) C.acutispina. (2)A.amurensis and P.borealis are the most closely related to each other and more recent species which evolved later. (3)A.japonica is more closely related to D.nipon than to other species. (4)C.acutispi
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na is the most distant species of the five members. These electrophoretic results were discussed through the detailed comparison with molecular and non-molecular data, and the differentiation process of five species was speculated.
2.Genetic variation and differentiation in two conspecific local populations of the two echinoderms, Strongylocentrotus nudus (Echinoidea) and Asterina pectinifera (Asteroidea) from northern Japan were studied by enzyme electrophoresis. A.pectinifera showed much higher genetic variability than other shallow water echinoderms, and it may be due to the large population size. The genetic distances between two populations were 0.006 for S.nudus and 0.041 for A.pectinifera, and the allele frequencies at three genetic loci were significantly different between populations. These results suggest that the genetic differentiation has been accomplished in some degree between two local populations of each species. We discussed the relation between the divergence time of two populations estimated from genetic distance and the paleogeographical history of the Tsugaru Strait. Less
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