| 摘要: |
| 采用微卫星DNA技术对中国对虾人工选育快速生长基础群体和4个连续世代共计100个个体进行了遗传分析。对8个基因位点进行了扩增,共得到71个等位基因。每个位点的等位基因数从6到16不等,其大小在159—600bp之间, PIC(PolymorphismInformationContent)值为0.6628—0.9051,基因型数为17—67。5个世代群体的平均杂合度分别为0.7188、0.5687、0.6188、0.6438、0.66937。从F-检验的数据来看,配对比较Fst值表明5个世代群体间的遗传分化程度较弱。Fis值的计算结果表明,有5个群体位点杂合度处于过剩状态,但对整个群体而言,5个世代群体均表现为一定程度的杂合子缺失。通过计算每个位点的等位基因数(na)、有效等位基因数(αe)、基因型数目(G)、最高频率等位基因的频率(F),以及基于基因型的P值,比较了5个群体的遗传变化。另外,5个世代群体间的相似性系数以及彼此间的遗传距离,体现出人工选育群体间的遗传分化程度较低,说明5个世代群体间的遗传分化程度较低,还有较大的选育潜力,可以继续保持遗传响应。 |
| 关键词: 中国对虾 微卫星 遗传变异 选择育种 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目,30271038号;山东省自然科学基金资助项目,Y2002D02号;国家重点基础研究发展规划“973”课题资助项目,1999012009号;国家“863”项目资助,2003AA603021号 |
|
| GENETIC DIVERSITY ANALYSIS ON SELECTED POPULATIONS OF SHRIMP FENNEROPENAEUS CHINENSIS BY MICROSATELLITE |
|
ZHANG Tian-Shi, WANG Qing-Yin, LIU Ping, LI Jian, KONG Jie
|
|
Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071
|
| Abstract: |
| Selective breeding on growth character of shrimp Fenneropenaeus chinensis has been conducted since 1997, and six successively bred stocks were produced between 1997 and 2002 at breeding base of the Yellow Sea Fisheries Research Institute, Qingdao, China. Samples of FP, CP3, CP4, CP5 and CP6, were randomly collected throughout the indicated pond area. Tail muscle tissue from shrimp mostly adults and sub-adults was collected. Samples were stored frozen (-20°C) until transported to Yellow Sea Fisheries Research Institute where they were kept at -80°C until genetic analysis was performed.
Total DNA was extracted from tail muscle. DNA quality controls were performed using agarose gel electrophoresis and only samples with good DNA quality were used for microsatellite analysis. Eight microsatellite primers were designed according to small-size fractionated genomic libraries of F. chinensis. Optimal results were obtained by optimizing quantity of reagents and reaction conditions. Under the optimal conditions, PCR was performed for analyzing the genetic diversity of different selected populations. All samples were run next to a known sequence in order to determine the size. To avoid inaccuracy in scoring due to differences in gels, a control DNA sample was included in each set of samples for each gel.
Eight microsatellites were used to analyse the genetic diversity of different selected populations of shrimp F. chinensis All eight microsatellite loci were polymorphic. A total of 71 alleles were found over all the loci. The number of alleles per locus ranged from 6 to 16, with allele size ranging from 159bp to 600bp. PIC ( Polymorphism Information Content ) per locus ranged from 0.6628 to 0.9051. The number of genotypes per locus ranged from 17 to 67. The average heterozygosity of the founder, 3rd, 4th, 5th and 6th generation were 0.7188, 0.5687, 0.6188, 0.6438 and 0.66937, respectively. Pair-wise Fst values among five populations were also low (Fst<0.05) suggesting low genetic differentiation between each two populations. Furthermore, five cases of observed heterozygosity excess (Fis<0) were observed in all populations. As far as the total population was concerned, the results based on the ‘null allele’ data set showed that observed heterozygosity deficiency occurred at all of the loci tested. Genetic differences among the five populations were also detected based on the number of alleles per locus (na), the effective number of alleles (αe), number of genotypes of per locus (G), frequency of the most common allele (F) , and perform chisquare (X2) tests to est imate the probability (P) of significant deviation from Hardy-Weinberg Equilibrium (HWE). In addition, Neics genetic distance (Nei, 1972, 1978) genetic distance among five populations ( FP, CP3, CP4, CP5 and CP6) were calculated. Fst values and pairwise Fst values showed that the genetic structure has changed within populations due to artificial selection and genetic differentiation index indicated there was not obvious differentiation among the five populations. In summary, data showed that genetic differentiation among the five selected generations was weaker, and there is potentiality for further selection. |
| Key words: Fenneropenaeus chinensis, Microsatellites, Genetic diversity, Selective breeding |
