【作者】 吴艳；

【导师】 刘小林； 侯水生；

【作者基本信息】 西北农林科技大学 ， 动物遗传育种与繁殖， 2005， 硕士

【摘要】 本研究利用微卫星标记技术,分析了北京鸭(Z1 和Z4)、樱桃谷鸭、奥白星鸭、绍鸭和番鸭(每个群体50 个个体)在20 个微卫星基因座的遗传多样性,探讨了各群体内的遗传变异和各群体间的遗传关系,计算了等位基因频率、群体杂合度(H)、有效等位基因数、多态信息含量、群体间的Nei 氏标准遗传距离(Ds)和DA遗传距离等,并利用Ds 和DA遗传距离分别构建了6 个鸭群体的系统聚类图。研究结果如下:　1.利用所选的20 个微卫星基因座对6 个鸭群体的300 个个体进行PCR 扩增,得到特异性的扩增产物。共检测到281 个等位基因,平均每个基因座14 个等位基因,最少为10 个;有效等位基因数目总共为104.43,有效等位基因数小于实际观察等位基因数,这是等位基因分布不均匀的结果。同时进行优势等位基因分析,结果表明:20 个微卫星基因座都有优势等位基因存在。　2.哈代-温伯格平衡检验结果表明:6 个群体在这20 个微卫星基因座上均处于遗传不平衡状态,究其原因有随机交配发生偏移、遗传漂变及选择等因素。其中选择所造成的影响最大,其次为随机交配发生的偏移以及遗传漂变。　3.根据统计结果可知:20 个微卫星基因座都为高度多态性基因座,平均多态信息含量在0.5968~0.8723 之间,6 个群体具有丰富的遗传多样性。6 个群体的基因杂合度变化范围在0.5886~0.8881 之间,杂合度较高。　4.遗传分化系数表明:AJ272581 座位的遗传分化系数(GST)估算值最大,为0.2185;其次为AJ272579、AJ515900(分别为0.1748、0.1047);最小的是AJ515895 座位,GST估计值为0.0205。说明这些基因座在不同群体间的遗传分化分别占总群杂合度的21.85%、17.78%、10.47%和2.05%。　5.用DISPAN软件分别计算了6个鸭群体之间的Nei氏标准遗传距离和DA遗传距离,并用该软件对其进行聚类,结果表明:由DA遗传距离用邻近结合法(NJ 法)聚类所得的结果与各群体之间的历史起源、地理位置、形态特征等基本吻合。用DA遗传距离将6个群体分为两类:Ⅰ类:北京鸭Z4、奥白星鸭、北京鸭Z1、樱桃谷鸭和绍兴鸭聚为一类。在这五个群体中北京鸭Z4 首先与奥白星鸭聚到一起,然后又与北京鸭Z1 相聚,再与樱桃谷鸭相聚,最后绍兴鸭又与它们在较近的距离聚在一起。Ⅱ类:番鸭聚为一类。　6.F-统计量分析表明:各微卫星基因座的杂合性基因多样性的比率(FST)的变化范围是从基因座AJ515895 的0.0205 到基因座AJ515896 的0.2558,平均值为0.0936;基更多还原

【Abstract】 The genetic diversity of 20 microsatellite loci was analyzed with the microsatellite marker technology in six duck populations. The six populations concluded: Peking duck (Z1 and Z4), Cherry Valley duck, Aobaixing duck, Shaoxing duck and Muscovy duck. The thesis discussed the genetic variation within population and among populations. Allele gene frequency, mean heterozygosisty, effective number of alleles, PIC, the Nei standard genetic distance and D_A genetic distance were calculated. Clustering dendrograms were obtained from Ds and D_A genetic distance. The results were as follows: 1. The 20 microsatellite loci were selected and the results of the PCR in 300 samples of the 6 duck populations were got in every locus. 281 alleles were tested in all the loci and the mean allelic number of per locus was 14, the least locus was 10. The efficient allelic number was 104.43. The efficient allelic number was less than the observed allelic number, this was the result of the alleles distributing unequally. And the dominant allele was analyzed, the results showed that the dominant allele was existed in all loci. 2. The Hardy-Weinberg equilibrium analysis revealed that remarkable genetic disequilibrium was showed at all the loci in 6 duck populations. The reasons may be that the excursion occurred in random mating, the random genetic drift and breeding was existed in 6 populations. In those, the breeding was the main reason. 3. The results showed that all of the 20 microsatellite loci had the high diversity, the mean polymorphic information content (PIC) value was between 0.5968~0.8723, which indicated that the 6 populations had abundant genetic diversity. The mean heterozygosisty was between 0.5886~0.8881, showed that the six populations had higher heterozygosisty. 4. The cofficient of gene differentiation was the largest in AJ272581, the value was 0.2185; then the AJ272579, AJ515900 (the value was 0.1748, 0.1047, respectively); the lowest one was AJ515895, its GST value was 0.0205. The result showed that the genetic differentiation among different populations was about 21.85%, 17.78%, 10.47% and 2.05% in the total population heterozygosisty. 5. The Nei,s standard genetic distance and DA genetic distance among the six duck populations were estimated with the DISPAN soft. The dendrograms were drawed with the upper two genetic distances. The reault showed that the dendrogram of DA genetic distance was similar with the origin, geography and character of the six duck populations. The six populations were clustered two groups. In the first group, Peking duck Z4 and Aobaixing duck clustered first, then the Peking duck Z1, Cherry Valley duck, at last, the Shaoxing duck was clustered with them. The Muscovy duck clustered another group. 6. The F-statistic analysis indicated that the FST of different locus varied from 0.0205 (in AJ515895) to 0.2558 (in AJ515896), and the average was 0.0936. The Nm was from 0.7273 (in AJ515896) to 11.9429, the mean was 2.4203. The result of cluster was consisitent with origin, geography, trait character of breed. It was proved that DS and DA genetic distance were appropriate to microsatellite when used to reconstruct phylogenetic tree. The information about population genetic relationship estimated by microsatellite may be useful as an initial guide in evaluating the value of genetic variation, and developing conservation strategies.更多还原