【作者】 张礼生；

【导师】 张青文；

【作者基本信息】 中国农业大学 ， 农业昆虫与害虫防治， 2004， 博士

【摘要】 染色体是生物遗传物质的载体，其结构特征具有相对恒定性，对染色体进行分析研究可揭示生物间染色体结构差异，反映生物的遗传多样性及系统演化路线。对染色体进行研究的细胞遗传学是遗传学与细胞学相互交叉与结合的产物，是旨在阐明生物有机体遗传与变异细胞学基础的科学。对昆虫染色体的研究，可以丰富昆虫遗传学的理论内涵与知识体系，揭示昆虫的种类演替、种间进化、种内进化的客观规律，为昆虫分类系统建立、近缘种区分乃至种下分类提供新方法和技术，并指导害虫的遗传防治，也为探明昆虫抗药性形成的机理提供了新的途径。 棉铃虫和烟青虫是我国重要的农业害虫，其种间杂交可育。为揭示二者的细胞遗传学规律，本论文研究了二者核型特征、有丝分裂与减数分裂期间染色体行为、联会复合体、染色体变异等细胞遗传学特征，总结比较其差异，并比较了棉铃虫与烟青虫杂交子代的染色体特征，为分子遗传学深入研究奠定基础，也为发展对其高效防治新途径提供参考。 1、采用HSG显带和常规C显带法，对棉铃虫和烟青虫进行有丝分裂中期与减数分裂粗线期核型分析显示，棉铃虫与烟青虫单倍体数目为n=31条，部分染色体为弥散型着丝粒类型。棉铃虫染色体长从1.64μm到5.99μm，按Lima-De-Faria标准，其单倍体中含7条中型染色体和24条小型染色体。烟青虫染色体长从1.27μm到5.01μm，整体较棉铃虫为短，方差分析显示二者差异极显著，按Lima-De-Faria标准，烟青虫单倍体中含5条中型染色体和26条小型染色体。相比而言，棉铃虫有80％的分裂相染色体为31条，而烟青虫仅有50％为31条，说明烟青虫染色体多态性更为显著，而棉铃虫相对稳定。 2、分析棉铃虫与烟青虫卵的有丝分裂、性母细胞的减数分裂过程，二者染色体行为未见明显差异。 3、棉铃虫、烟青虫的联会复合体的侧生组分和中央组分的形态构造清晰可见；联会复合体核型分析显示，棉铃虫与烟青虫的单倍体中联会复合体数目均为31条，且棉铃虫与烟青虫联会复合体长度间差异不显著。二者粗线期染色体长与联会复合体长极显著相关，利用联会复合体代替减数分裂粗线期进行核型分析是可行的。 4、棉铃虫、烟青虫的性染色体在C-带、G-带等染色制片中不能被准确鉴别，但可在雌虫联会复合体中发现异型染色体即性染色体，其中较长者为W染色体，较短者为Z染色体，验证了鳞翅目蛾类昆虫性染色体为ZZ/ZW型的规律，为棉铃虫、烟青虫性染色体是ZZ／ZW型提供了细胞学证据。 5、棉铃虫与烟青虫杂交子代的染色体分析，其核型为单倍体n=31，与亲本无差异。染色体长度变化在2.4lμm到4.73μm之间，与亲本相比较，其变化幅度明显不如亲本变幅大。杂交子代联会复合体长度依然不如亲本变化幅度大。此外，杂交子代无论是雌性还是雄性，其联会复合体中均未发现异型染色体，其性染色体不能被准确识别，这一点明显与亲本有差异，显示杂交子代染色体已发生显著的变化。更多还原

【Abstract】 Chromosome is the carrier of biotic genetic material, and its structure has the feature of relative constancy. So, through the study of chromosome, we can get the disclosure of the structural differences among organisms, and the reflection of the hereditary diversity and the systematic evolution route of the creatures. Cytogenetics, which focus on the research of chromosome, is the product of the reciprocal chiasmata and combination of genetics and cytology, it aims to demonstrate basic science of organic heredity and variation cytology. The study of insect chromosome can enrich the theory meaning and knowledge system of insect genetics, and reveal the natural rules of species succession, interspecific evolution, and intraspecific evolution of insect. Meanwhile, the study can also offer new method and technique to establish insect taxonomical system, specification of kindred, and subspecies identification. Moreover, it can be made the use of the genetic management of pests, and offer the new way to explore the mechanism of pest resistance to chemicals.Helicoverpa armigera (Hiibner) and H. assulta (Guenee) are critical agricultural pests in China, Their interspecific hybrid can reproduce. In order to reveal the genetic rules between the two pests, we took a study of the chromosome of H. armigera and H. assulta, which contained the contents as following: the karyotype feature, the behaviors of the chromosome during the period of mitosis and meiosis, synaptonemal complex, chromosome variance, and F1 generalization comparison.1 With the method of HSG-banding and normal C-binding technique, we made an analysis of the karyotypes for H. armigera and H. assulta during the period of mitosis metaphage and meiosis pachytene. The result showed that the numbers of haploid of H. armigera and H. assulta were all 31, part of chromosomes were of the kind of holocentromere. The chromosome length of H. armigera ranged from 1.64un to 5.99um. With Lima-De-Faria as the standard, there were 7 middle-sized and 24 small-sized chromosomes among all its haploid. The chromosome length of H, assulta ranged from 1.27 um to 5.01 Mm. The chromosome length of H, assulta was shorter than that of H, armigera, and there was very significant difference between the two pests from the result of variance analysis, there were 5 middle-sized and 26 small-sized chromosomes among all its haploid.Comparatively speaking, 80% numbers of the chromosomes of H, armigera in split phase were 31, whereas, there are only 50% were 31 in the case of H. assulta. Consequently, it demonstrated that the chromosome polymorphisms of//, assulta turn out to be much more obvious, and the chromosome of//. armigera was relatively stable.2 Through the analysis of the mitosis of egg and the meiosis of auxocyte, it appeared no significant difference of chromosome behavior in these procedures.3 For H. armigera and H. assulta, we got a clear show of the shape and construction of synaptonemal complex’s lateral element and central element; The analysis of synaptonemal complex karyotype showed that, in the body of H. armigera and H. assulta, the number of synaptonemalcomplex among haploids were all 31, and it also turned out that the lengths of synaptonemal complex of H. armigera and H. assulta showed no significant difference according to variance analysis. The correlation analysis of the lengths in pachytene and the synaptonemal complex of the two pests showed that the two had an obvious linear dependence. So, the method that tries to take the place of meiosis pachytene by synaptonemal complex is feasible.4 The chromosomes of H. armigera and H. assulta can not be detected correctly during staining flaking of C-band and G-band. Whereas, we can find heterotypic chromosome -sex chromosome in female synatonemal complex when doing the analysis of synatonemal complex. With the further analysis, we determined that the longer one is chromosome W, and the shorter one is chromosome Z. According to all the work we have done above, it fairly verified the law that the sex更多还原