[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea sn...[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea snakes.[Methods]All COI and cytb gene sequences on GenBank were searched and downloaded.After the comparison with Mega software,clustering trees of MrBayes system were established.[Results]Interspecies distances were greater than intraspecies distances for the two genes.The topological structures of their molecular hierarchical clustering trees were clear,and the support rates were high.[Conclusions]Therefore,it is concluded that not the DNA barcode of each species must be gene COI.Cytb is more suitable in terms of the mitochondrial gene of sea snakes.展开更多
为评估种质资源状况被世界自然保护联盟(International Union for Conservation of Nature, IUCN)评定为易危物种的褐石斑鱼(Epinephelus bruneus)野生种群的遗传多样性和遗传分化水平,采用PCR方法测定褐石斑鱼西太平洋海区的中国海南岛...为评估种质资源状况被世界自然保护联盟(International Union for Conservation of Nature, IUCN)评定为易危物种的褐石斑鱼(Epinephelus bruneus)野生种群的遗传多样性和遗传分化水平,采用PCR方法测定褐石斑鱼西太平洋海区的中国海南岛(HN)、福建厦门(XM)和韩国济州岛(HG)3个地理群体的线粒体细胞色素b(Cytb)基因的部分序列,并对其基因序列遗传变异、谱系结构和群体扩张历史特征进行分析。结果显示,褐石斑鱼3个地理种群(88个个体)共检测出18个多态位点,共有7种单倍型;各地理群体遗传多样性水平较低,而且单倍型在群体间分布不均,韩国群体遗传多样性最高,中国海南和厦门群体遗传多样性较低。地理距离最远的韩国群体和中国海南群体遗传分化最高(F_(ST)=0.177 5),地理距离最近的中国海南群体和厦门群体的遗传分化最低(F_(ST)=0.013 4)。Mantel检验结果显示,3个褐石斑鱼群体间遗传距离和地理距离间存在显著相关,距离隔离(Isolation by Distance, IBD)是褐石斑鱼群体遗传分化的主要因素。褐石斑鱼群体遗传变异主要来源于群体内,群体间存在中度遗传分化(F_(ST)=0.097 1)。褐石斑鱼Cytb基因单倍型网络图表现为简单星形结构,符合群体扩张的历史特征。Tajima′s D和Fu′s Fs中性检验结果也证实西太平洋海区褐石斑鱼群体存在扩张的历史特征。本研究结果表明,西太平洋海区的褐石斑鱼总体遗传多样性水平较低,野生种质资源极易受到渔业捕捞和气候变化的影响而衰退,在全球气候变化的背景下,急需加强其种质资源的保护工作。展开更多
Mitochondrial cytochrome b (Cytb), one of the few proteins encoded by the mitochondrial DNA, plays an important role in transferring electrons. As a mitochondrial gene, it has been widely used for phylogenetic analysi...Mitochondrial cytochrome b (Cytb), one of the few proteins encoded by the mitochondrial DNA, plays an important role in transferring electrons. As a mitochondrial gene, it has been widely used for phylogenetic analysis. Previously, a 949-bp fragment of the coding gene and mRNA editing were characterized from Prorocentrum donghaiense, which might prove useful for resolving P. donghaiense from closely related species. However, the full-length coding region has not been characterized. In this study, we used rapid amplification of cDNA ends (RACE) to obtain full-length, 1 124 bp cDNA. Cytb transcript contained a standard initiation codon ATG, but did not have a recognizable stop codon. Homology comparison showed that the P. donghaiense Cytb had a high sequence identity to Cytb sequences from other dinoflagellate species. Phylogenetic analysis placed Cytb from P. donghaiense in the clade of dinoflagellates and it clustered together strongly with that from P. minimum. Based on the full-length sequence, we inferred 32 editing events at different positions, accounting for 2.93% of the Cytb gene. 34.4% (11) of the changes were A to G, 25% (8) were T to C, and 25% (8) were C to U, with smaller proportions of G to C and G to A edits (9.4% (3) and 6.2% (2), respectively). The expression level of the Cytb transcript was quantified by real-time PCR with a TaqMan probe at different times during the whole growth phase. The average Cytb transcript was present at 39.27±7.46 copies of cDNA per cell during the whole growth cycle, and the expression of Cytb was relatively stable over the different phases. These results deepen our understanding of the structure and characteristics of Cytb in P. donghaiense, and confirmed that Cytb in P. donghaiense is a candidate reference gene for studying the expression of other genes.展开更多
为准确掌握柔鱼的种群遗传结构,拟通过线粒体DNA的COI和Cytb基因序列分析方法对柔鱼不同产卵季节群体的遗传多样性和遗传结构进行研究。经PCR扩增与测序分别获得600 bp COI与481 bp Cytb基因序列。基于COI基因序列分析得到的单倍型数、...为准确掌握柔鱼的种群遗传结构,拟通过线粒体DNA的COI和Cytb基因序列分析方法对柔鱼不同产卵季节群体的遗传多样性和遗传结构进行研究。经PCR扩增与测序分别获得600 bp COI与481 bp Cytb基因序列。基于COI基因序列分析得到的单倍型数、单倍型多样性指数、核苷酸多样性指数及平均核苷酸差异数分别为24、(0.729±0.033)、(0.005 70±0.003 25)和3.421。基于Cytb基因序列分析得到的单倍型数、单倍型多样性指数、核苷酸多样性指数及平均核苷酸差异数分别为28、(0.852±0.016)、(0.006 45±0.003 73)和3.101。分析认为,北太平洋柔鱼2个产卵季节群体均具有较高的单倍型多样性指数和较低的核苷酸多样性指数。单倍型邻接树、两两群体间的Fst值以及AMOVA分析结果均表明,北太平洋柔鱼2个产卵季节群体间的遗传差异不显著,不存在显著的群体遗传结构。初步认为,该海域因缺乏地理上的障碍,加之北太平洋海流的作用以及柔鱼个体较强的游泳能力,使得群体之间具有较强的基因流。展开更多
基金Supported by Hainan Provincial Natural Science Foundation of China,High-level Talent Project(321RC587),Classification of sea snakes in the South Sea China based on molecular Systematics,morphology and climate modelSpecial Scientific Research Trial Production Project of Sanya City(2016KS05),Identification of sea snake species and construction of DNA barcoding based on molecular systematics.
文摘[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea snakes.[Methods]All COI and cytb gene sequences on GenBank were searched and downloaded.After the comparison with Mega software,clustering trees of MrBayes system were established.[Results]Interspecies distances were greater than intraspecies distances for the two genes.The topological structures of their molecular hierarchical clustering trees were clear,and the support rates were high.[Conclusions]Therefore,it is concluded that not the DNA barcode of each species must be gene COI.Cytb is more suitable in terms of the mitochondrial gene of sea snakes.
文摘为评估种质资源状况被世界自然保护联盟(International Union for Conservation of Nature, IUCN)评定为易危物种的褐石斑鱼(Epinephelus bruneus)野生种群的遗传多样性和遗传分化水平,采用PCR方法测定褐石斑鱼西太平洋海区的中国海南岛(HN)、福建厦门(XM)和韩国济州岛(HG)3个地理群体的线粒体细胞色素b(Cytb)基因的部分序列,并对其基因序列遗传变异、谱系结构和群体扩张历史特征进行分析。结果显示,褐石斑鱼3个地理种群(88个个体)共检测出18个多态位点,共有7种单倍型;各地理群体遗传多样性水平较低,而且单倍型在群体间分布不均,韩国群体遗传多样性最高,中国海南和厦门群体遗传多样性较低。地理距离最远的韩国群体和中国海南群体遗传分化最高(F_(ST)=0.177 5),地理距离最近的中国海南群体和厦门群体的遗传分化最低(F_(ST)=0.013 4)。Mantel检验结果显示,3个褐石斑鱼群体间遗传距离和地理距离间存在显著相关,距离隔离(Isolation by Distance, IBD)是褐石斑鱼群体遗传分化的主要因素。褐石斑鱼群体遗传变异主要来源于群体内,群体间存在中度遗传分化(F_(ST)=0.097 1)。褐石斑鱼Cytb基因单倍型网络图表现为简单星形结构,符合群体扩张的历史特征。Tajima′s D和Fu′s Fs中性检验结果也证实西太平洋海区褐石斑鱼群体存在扩张的历史特征。本研究结果表明,西太平洋海区的褐石斑鱼总体遗传多样性水平较低,野生种质资源极易受到渔业捕捞和气候变化的影响而衰退,在全球气候变化的背景下,急需加强其种质资源的保护工作。
基金Supported by the National Natural Science Foundation of China (Nos.40406028, 40706044)
文摘Mitochondrial cytochrome b (Cytb), one of the few proteins encoded by the mitochondrial DNA, plays an important role in transferring electrons. As a mitochondrial gene, it has been widely used for phylogenetic analysis. Previously, a 949-bp fragment of the coding gene and mRNA editing were characterized from Prorocentrum donghaiense, which might prove useful for resolving P. donghaiense from closely related species. However, the full-length coding region has not been characterized. In this study, we used rapid amplification of cDNA ends (RACE) to obtain full-length, 1 124 bp cDNA. Cytb transcript contained a standard initiation codon ATG, but did not have a recognizable stop codon. Homology comparison showed that the P. donghaiense Cytb had a high sequence identity to Cytb sequences from other dinoflagellate species. Phylogenetic analysis placed Cytb from P. donghaiense in the clade of dinoflagellates and it clustered together strongly with that from P. minimum. Based on the full-length sequence, we inferred 32 editing events at different positions, accounting for 2.93% of the Cytb gene. 34.4% (11) of the changes were A to G, 25% (8) were T to C, and 25% (8) were C to U, with smaller proportions of G to C and G to A edits (9.4% (3) and 6.2% (2), respectively). The expression level of the Cytb transcript was quantified by real-time PCR with a TaqMan probe at different times during the whole growth phase. The average Cytb transcript was present at 39.27±7.46 copies of cDNA per cell during the whole growth cycle, and the expression of Cytb was relatively stable over the different phases. These results deepen our understanding of the structure and characteristics of Cytb in P. donghaiense, and confirmed that Cytb in P. donghaiense is a candidate reference gene for studying the expression of other genes.
文摘为准确掌握柔鱼的种群遗传结构,拟通过线粒体DNA的COI和Cytb基因序列分析方法对柔鱼不同产卵季节群体的遗传多样性和遗传结构进行研究。经PCR扩增与测序分别获得600 bp COI与481 bp Cytb基因序列。基于COI基因序列分析得到的单倍型数、单倍型多样性指数、核苷酸多样性指数及平均核苷酸差异数分别为24、(0.729±0.033)、(0.005 70±0.003 25)和3.421。基于Cytb基因序列分析得到的单倍型数、单倍型多样性指数、核苷酸多样性指数及平均核苷酸差异数分别为28、(0.852±0.016)、(0.006 45±0.003 73)和3.101。分析认为,北太平洋柔鱼2个产卵季节群体均具有较高的单倍型多样性指数和较低的核苷酸多样性指数。单倍型邻接树、两两群体间的Fst值以及AMOVA分析结果均表明,北太平洋柔鱼2个产卵季节群体间的遗传差异不显著,不存在显著的群体遗传结构。初步认为,该海域因缺乏地理上的障碍,加之北太平洋海流的作用以及柔鱼个体较强的游泳能力,使得群体之间具有较强的基因流。
