【作者】 王朝明；

【导师】 邹桂伟； 魏开建；

【作者基本信息】 华中农业大学 ， 水产养殖， 2005， 硕士

【摘要】 本研究以大口鲇、鲇为亲本进行杂交试验并获得正交F₁,并从蛋白质（含同工酶）和DNA水平对两种鲇及其杂种F₁进行了比较研究,探讨三者间的遗传关系及杂种优势等问题,寻找能区分三种鲇的遗传标记。主要研究结果如下: 1.与对照组相比,杂交组受精率稍低,而孵化率、出苗率没明显差异,表明大口鲇（♀）×鲇鱼（♂）的杂交组合不存在繁殖障碍或繁殖障碍较小;杂种F₁生长（体重、体长）与母本大口鲇相近,t检验差异不显著（P>0.05）,而与父本鲇差异显著（P<0.05）,显示出一定的杂种优势。 2.在蛋白质（同工酶）水平,杂种F₁的蛋白质表型是双亲所有区带的总和,无多态性;杂种F₁的同工酶表型复杂:或者继承亲本酶谱的部分酶带、丢失亲本的部分酶带,或者出现双亲皆无的酶带;同工酶具有组织特异性、物种特异性;EST和ADH同工酶存在明显的多态性,尤以EST明显。在肾脏和脾脏的基因座位EST-4和肝脏ADH的基因座位A₂与B₂¹¹⁷可作为区分大口鲇和其它两种鲇的生化遗传标记。 3.在DNA水平,筛选的22个随机引物共产生217条带,单一引物扩增出1-12条DNA带,大小在200—3500bp间。大口鲇、鲇及其杂种F₁群体内的遗传相似性指数分别是0.986、0.878、0.961,可见杂种F₁群体内遗传相似性指数介于亲本群体的遗传相似性指数之间。杂种F₁与大口鲇、鲇的遗传相似性指数为0.731、0.615,表明亲本与子代间的遗传属于非对等遗传;亲本间的相似性指数为0.423,说明两者基因组成有较大的相似性,从分子水平证实了该杂交具有较大的亲合性。3个群体内都存在一定的多态性,多态比例分别为6.36%、41.13%、15.13%。同时杂种F₁中还扩增出非亲本带。引物OPH-04、OPH-06、OPH-12、OPH-15、OPH-16、OPH-17、OPH-18、OPI-04、OPI-07、OPI-08、OPI-13、OPI-14和OPI-20可以建立有效的区分三种鲇的遗传标记。更多还原

【Abstract】 The article tested the cross experiment of Silurus meridionalis Chen and Silurus asotus Linnaeus, then investigated and compared Silurus meridionalis Chen, Silurus asotus Linnaeus and their hybrid F₁ at different levels （proteins and DNA） in order to search their genetic marker and discuss their genetic affinity and heterosis. The major research results of this study are as follows:1 .Compared to the controls, the results showed that the fertility rate is little lower, hatching rate and the stocked rate have no obvious difference which suggested there was no or little breeding handicap; Through paired t-test, the growth of the hybrid F₁ is similar to control Ⅰ and no significant difference exist between them ,but significant difference exist between the hybrid and the control Ⅱ, which suggested the hybrid F₁ was characterized by its faster growth rate.2. The results showed that the proteinic phenotypes of the hybrid F₁ expressed all of the parents’ bands which did not have any polymorphism, while the isozymic phenotypes is very complex which inherited part of the parents and lost another part, or appeared isozymic phenotypes which did not appear in parents. The specificities of species and tissues were expressed in isozymes. Three kinds of fish had obvious polymorphism in the electrophergram of EST and ADH, especially in the electrophergram of EST. The biochemical genetic markers （EST-4）that can distinguish Silurus meridionalis Chen from the other two kinds were detected in electrophergram of EST from the kidney and spleen, also biochemical genetic markers (A₂ and B₂¹¹⁷) can be found in electrophergram of ADH from liver.3. Of these primers, 22 primers produced well-amplified and reproducible band pattern. There were 1-12 bands ranging in size from about 200 to 3500bp in the Amplified products of a single primer. After excluding bands that were not clearly identifiable, atotal of 217 distinguishable fragments were compiled for phylogenetic relationship analysis. The inter-population similarity indexes was 0. 986, 0.878 and 0.961 respectively, which showed variation in the kinds of hybrids between its parents populations. The genetic similarity index of the amplified DNA bands between the hybrid Fi and Silurus meridionalis Chen was 0.731, and that of the amplified DNA bands between hybrid Fi and Silurus asotus Linnaeus was 0.615. The similarity index of the amplified DNA bands between Silurus meridionalis Chen and Silurus asotus Linnaeus was 0.423. There are polymorphic bands within populations, the ratio of polymorphic loci are 6. 36%, 41. 13%, 15. 13% respectively. Moreover, 5 specific bands were found only in the hybrid Fi, the non-parentage bands ratio of the hybrid was 0.023. The results not only provided the specific molecular markers of the hybrid Fj, but also demonstrated that the hybrid Fi inherited a little more genetic materials from their parents. The amplified DNA bands of primers OPH-04, OPH-06, OPH-12, OPH-15, OPH-16, OPH-17, OPH-18, OPI-04, OPI-07, OPI-08, OPI-13, OPI-14 and OPI-20 can distinguish Silurus meridionalis Chen from the other two kinds.更多还原