1990 Fiscal Year Final Research Report Summary
A Study of Molecular Population Genetics on the Aspect of Edaptive evolution in Drosphila
| Project/Area Number |
01480004
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
遺伝学
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| Research Institution | Kyushu University |
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Principal Investigator |
HARADA Ko Kyushu Univ, Biology, Research Associate, 理学部, 助手 (40150396)
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| Co-Investigator(Kenkyū-buntansha) |
TAKANO Toshiyuki Kyushu Univ. Biology, Research Associate, 理学部, 助手 (90202150)
YAMAZAKI Tuneyuki Kyushu Univ. Biology, Associate Professor, 理学部, 助教授 (10108649)
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| Project Period (FY) |
1989 – 1990
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| Keywords | DNA polymorphism / molecular evolution / Drosophila / Transpasable element / Transposition rate / P element |
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| Research Abstract |
The generality of the neutral theory of molecular evolution (Kimura, 1968) has been accepted in the course of accumulation of molecular date of genes. Mukai and his colleagues have shown that most of the protein polymorphisms are selectively neutral. The purpose of this study is to investigate the genetic variation, that is the source of adaptive evolution, in molecular level and testify whether the neutral theory is operational for these experimental data.
Following things have become clear in this study. 1. We have shown that there is north to south cline in the additive genetic variance in viability. This is suggesting some of balancing selection is operating on these variations population. We studied restriction enzyme in southern polymorphism in four gene regions (Adh, Amy, Gpdh, Punch) in north (Amori) and south (Ogasawara) populations. There is no significant difference in restriction site polymorphisms, but significant difference was detected in the polymorphisms in insertions a
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nd deletions. Large amount of difference was observed in the southern population. This fact may suggest that excess additive genetic variance in the northern population is reflecting the cumulative effect of these variations. 2. The duplication or triplication of Gpdh gene is found to be polymorphic. It is pointed that gene duplication is important mechanism of gene evolution. These variation appeared to be maintained in the balance between mutational occurrence and purifying selection or by random genetic drift. Furthermore, we obtained an evidence that these genes evolved in concerted fashion by unequal crossing-over. 3. Transposable elements occupy about 10% of Drosophila genome and they often create complicated mutations. Transposition rate is one of the important parameter in evaluating the contribution of these mutations to adaptive evolution. Using mutation accumulation lines, we estimated transposition rates of several transposable elements. This the first reliable of such estimations. 4. We compared the distribution of several transposable elements in southern and northern populations. Some copia like elements shows difference in number between two populations. 5. We investigated the population structure concerning to P element activity and molecular structure. We obtained an evidence that in the course of invasion of P element, it causes large amount of genetic loads. There is variation in the length of P element. There is interpopulational difference in the distribution of complete size elements, but the frequency of KP like elements is increasing in all the populations investigated. Less
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