摘要
采用同工酶电泳、RAPD引物PCR扩增和线粒体DNA细胞色素b基因全序列3种方法,对鄱阳湖3种斑纹泥鳅的遗传结构进行分析。同工酶电泳显示3种斑纹泥鳅在LDH、MDH和EST这3种同工酶之间存在群体和组织差异;RAPD试验结果显示6条RAPD引物在18尾鄱阳湖泥鳅个体中共扩增出了169条不同分子量的RAPD标记,其中多态性带101条,多态性带的比例为59.56%,平均每个引物产生9.39条带和5.61条多态性带,不同斑纹泥鳅的遗传多样性指数显示3种斑纹泥鳅的遗传水平处于较高水平。以特异性引物进行PCR扩增,获得了1140bp的细胞色素b基因全序列。结果显示,3种不同斑纹泥鳅中检测出了1个共有单倍型和3个特有单倍型。与共有单倍型相比,大花斑泥鳅特有单倍型有91个变异位点,而小花斑泥鳅与无花斑泥鳅特有单倍型的变异位点为20和24个。基于单倍型构建的NJ树和MP树,显示大花斑泥鳅的特有单倍型EU145023处于独立的分支上,这反映出鄱阳湖地区不同斑纹的泥鳅之间在线粒体DNACytb基因中出现了一定距离的分化。
Loaches is one group of small freshwater fish dwelling in slow to moderately swift water, widely distributes in rivers and lakes. Poyang Lake, the biggest fresh water lake in China, has a rich biodiversity in fishes. The loaches of the Poyang Lake can be divided into three kinds based on skin spot： the big-spot loaches, the small-spot loaches and the non-spot loaches. Preliminary research indicated that the biological character of its skin spot was stable, which belongs to quantitative traits loci （QTL）. In this study, with the expectation, to provide the evidence of theory in well-bred loach selection, isozyme electrophoresis, RAPD and mtDNA Cyt b gene sequencing were applied to investigate the genetic diversity of the three different kinds of loaches. Using discontinued polyacrylamide gel electrophoresis to analysis the isozymes, results showed that there were some genetic differences among the three kinds loaches based on LDH, MDH and EST isozymes. These differences were not only among different tissues, e.g. LDH4 only existed in gonad tissue just as m-MDH-A in muscle tissue and EST-2 in liver tissue, but also among the three kind loaches, e.g. m-MDH-B only existed in muscle tissue of the big-spot loach but not in other two kinds loaches, cLDH was only existed in the liver tissue of the small-spot and non-spot loached not find in the big-spot loach. RAPD technique, as an important tool for genetic study, was widely used in identification of species. 6 random primers, with more stable and reproducible characteristics, were selected from 35 random primers in RAPD to evaluate the genetic diversity. 169 distinguishable DNA fragments were amplified in all, varying in length from 200 to 1800 bp, 101 of them （59.56%） were polymorphic. Each primer could amplify DNA fragments varied from 8 to 11, 9.39 fragments per primer, including 5.61 polymorphic fragments. The shannon’s index was 0.3750 in the big-spot loaches, 0.2706 in small-spot and 0.2656 in nonespot loaches. So the genetic similarity index by the result of RAPD in the three kind loach were very high from the nuclear DNA. The Cyt b gene, 1140bp sequences, was obtained by PCR amplification in the three kind loaches. Four haplotypes were identified from 28 samples with 113 variation site, one was the mutual haplotype and others were endemic haplotypes. The endemic haplotype which presented only in big-spot loach had 91 variation sites compared to the mutual haplotype, but the endemic haplotype in small-spot and non-spot loach only had 20 and 24 variation sites. With Myxocyprinus asiaticus as outgroup, the phylogenetic trees were analyzed using the neighbor joining （NJ） method and the maximum parsimony （MP） in MEGA 4.0. The result showed that the haplotype of the big-spot loach were clustered into another branch with high confidence level, it also indicated that there were a certain genetic differences among the three kinds loached based on mitochondrial cytochrome b gene sequences. The genetic diversity of the three kind loaches in Poyang Lake, based on the results of isozymes, nuclear DNA （RAPD analysis） and mtDNA （Cyt b gene analysis）, was abundant. Results also indicated that the loach in Poyang Lake might have population heterozygosis.
出处
《水生生物学报》
CAS
CSCD
北大核心
2010年第5期966-972,共7页
Acta Hydrobiologica Sinica
基金
国家重点基础研究发展计划"973"项目(编号:2004CB117401)资助
关键词
泥鳅
遗传多样性
同工酶
RAPD
细胞色素B
Loach （Misgurnus anguillicaudatus）
Genetic diversity
Isozyme
RAPD
Cyt b
