共查询到20条相似文献,搜索用时 0 毫秒
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Klaczko LB 《Genetica》2006,126(1-2):43-55
Drosophila mediopunctata belongs to the tripunctata group, which is the second largest Neotropical group of Drosophila with 64 species described. Here I review the work done with this forest dwelling species, and some applications of the methods
developed using it as a model organism, to other species. Specifically I look at: the phylogenetic status of the tripunctata group and its relation with other groups in the Hirtodrosophila-immigrans radiation; D. mediopunctata’s chromosome inversion polymorphism (altitudinal cline of frequencies and evidences of selection); the morphological variation
of the wing and the development and applications of the ellipse method to describe the morphology of the wing; the variation
on the number of aristal branches; the genetic basis of the polychromatism present in D. mediopunctata and its association with chromosome inversions; the sex-ratio trait and its use in the demonstration of Fisher’s principle; and, finally, the finding of the transposable P-element in this species.
This paper is respectfully dedicated to Prof. Sergio Olavo Pinto da Costa whose help was decisive in the initial stages of
our work. 相似文献
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JU. I. Ljubi 《Biometrical journal. Biometrische Zeitschrift》1978,20(5):511-529
This paper is a survey of some results obtained in evolutionary genetics by algebraical methods. The main topics: 1. Some special classes of algebras which arising in population genetics (stochastic, baric, BERNSTEINian, genetic etc.). 2. The BERNSTEIN'S problem and the stationary genetic structure. 3. The convergence to an equilibrium, the rate of convergence. 4. The exact linearization of evolutionary equation. 5. The exact formulae for evolutionary spectrum and for solution of the evolutionary equation. 相似文献
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Sohei Kondo 《Genetics》1974,78(1):149-161
Recent knowledge of UV-resistance mechanisms in microorganisms is reviewed in perspective, with emphasis on E. coli. Dark-repair genes are classified into "excision" and "tolerance" (ability to produce a normal copy of DNA from damaged DNA). The phenotype of DNA repair is rather common among the microorganisms compared, and yet their molecular mechanisms are not universal. In contrast, DNA photoreactivation is the simplest and the most general among these three repair systems. It is proposed that DNA repair mechanisms evolved in the order: photoreactivation, excision repair, and tolerance repair. The UV protective capacity and light-inducible RNA photoreactivation possessed by some plant viruses are interpreted to be the result of solar UV selection during a rather recent era of evolution. 相似文献
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R. B. Church 《Genetics》1974,78(1):511-524
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Artyom Kopp 《Current biology : CB》2012,22(23):R1004-R1006
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Clifford Zeyl 《Current biology : CB》2010,20(15):R637-R639
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The molecular analysis of the genetic systems controlling the main stages of nodule bacteria (rhizobia) interaction with a legume host (signaling at early stages and symbiotic nitrogen fixation) has shown that the widespread recombination of genetic material in free-living ancestors of rhizobia was an important factor in the evolution of these systems. These recombinations could be conditioned by a high content of repeated DNA sequences and the IS elements in the rhizobial genome. A high recombination activity of rhizobia is manifested in the panmictic structure of their populations, which is associated with frequency-dependent selection favoring rare recombinants. This selection is realized through the competition of virulent strains for the nodule formation and can be controlled by the genes whose expression depends on population density (via the quorum sensing mechanism). A high degree of panmixia in rhizobial populations is associated with their ecotypic polymorphism, manifested as the coexistence of symbiotic and nonsymbiotic strains. This type of polymorphism is caused by individual selection during the periodic changes of ecological niches (soil–plant host) in the rhizobia life cycle. The rhizobia–plant interaction stimulates selection in bacterial populations, which results in the increased levels of their heterogeneity and panmixia. The combination of individual and frequency-dependent selection types resulted in the high rates of symbiosis evolution and polyphyletic origin of diverse rhizobial species. 相似文献