1999 Fiscal Year Final Research Report Summary
Host-parasite coevolution in multilocus gene-for gene system
| Project/Area Number |
10640619
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生態
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
SASAKI Akira Kyushu Umiv., Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (90211937)
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| Co-Investigator(Kenkyū-buntansha) |
佐々木 顕 九州大学, 大学院・理学研究科, 助教授 (90211937)
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| Project Period (FY) |
1998 – 1999
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| Keywords | coevolution / gene-for-gene interaction / resistance / virulence / spatial structure / encapsulation / evolution of sex / parasite Red Queen |
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| Research Abstract |
We here examine mathematical model for the coevolution of parasite virulence and host resistance under multilocus gene-for-gene interaction. For sufficiently small costs of virulence and resistance, the degrees of parasite virulence and host resistance show coevolutionary cycles. Besides this coevolutionary cycle of a longer period, multilocus genotype frequencies show complex fluctuation in shorter periods. All the genotypes that have the same number of resistant/virulent alleles but at different loci coexist in both species, and their frequencies fluctuate with approximately equally displaced phases. If the cost of virulence is larger than a threshold, or the number of resistance loci is larger then a threshold, the coevolutionary outcome is the static polymorphism of singly (or doubly or more, depending on the cost of resistance) resistant genotypes in the host and avirulent monomorphism in the parasite, in which the host polymorphism can prevent the invasion of any virulent strain in the parasite. Thus though assuming empirically common type of asymmetrical GFG interactions, both host and parasite populations can maintain polymorphism in each locus and retain complex fluctuation. Implication to the Red Queen hypothesis for the evolution of sex is discussed.
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