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1.
The sequences of mitochondrial cytochrome b gene of cyprinid subfamily Leuciscinae are analyzed. Phylogenetic trees generated with methods of neighbor-joining, maximum likelihood and maximum parsimony with Phenacogrammus as an outgroup indicate that Leuciscinae is not a monophyletic group but includes two discrete subgroups. The East Asian group of the subfamily Leuciscinae, including the genera Ctenopharyngodon, Elopichthys, Luciobrama, Mylopharyngodon, Ochetobius, and Squaliobarbus, is close to Aristichthys and Hypophthalmichthys, and they form a monophyletic group which is distant from the leuciscine genera in Europe, Siberia and North America, such as Phoxinus, Leuciscus, Abramis, Rutilus, Chondrostoma, Alburnus, Opsopoedus, Lythrurus, and Pimephales. Our study suggests that the diversified East Asian group of the subfamily Leuciscinae should have an independent origination.  相似文献   

2.
1140 bp of cytochrome b gene were amplified and sequenced from 14 species of primitive cyprinid fishes in East Asia. Aligned with other ten cytochrome b gene sequences of cyprinid fish from Europe and North America retrieved from Gene bank, we obtained a matrix of 24 DNA sequences. A cladogram was generated by the method of Maximum likelihood for the primitive cyprinid fishes. The result indicated that subfamily Leuciscinae and Danioninae do not form a monophyletic group. In the subfamily Danioninae, Opsariichthys biden and Zacco platypus are very primitive and form a natural group and located at the root. But the genera in subfamily Danioninae are included in different groups and have not direct relationship. Among them, Aphyocypris chinensis and Yaoshanicus arcus form a monophyletic group. Tanichthys albonubes and Gobiocypris rarus have a close relation to Gobioninae. The genus Danio is far from other genera in Danioninae. In our cladogram, the genera in Leuciscinae were divided into two groups that have no direct relationship. The genera in Leuciscinae distributed in Europe, Sibera and North America, including Leuciscus, Rutilus, Phoxinus, N. crysole, Opsopoeodus emilae, form a monophyletic group. And the Leuciscinae in southern China including Ctenopharyngodon idettus, Mylopharyngodon piceus, Squalibarbus and Ochetobius elongatus have a common origination.  相似文献   

3.
The family Cyprinidae is one of the largest fish families in the world, which is widely distributed in East Asian, with obvious difference in characteristic size among species. The phylogeneUc analysis of cyprinid taxa based on the functionally important genes can help to understand the speciation and functional divergence of the Cyprinidae. The c-myc gene is an important gene regulating individual growth. In the present study, the sequence variations of the cyprinid c-myc gene and their phylogenetic significance were analyzed. The 41 complete sequences of the c-myc gene were obtained from cyprinids and outgroups through PCR amplification and clone. The coding DNA sequences of the c-myc gene were used to infer molecular phylogenetic relationships within the Cyprinidae. Myxocyprinus asiaticus (Catostomidae), Misgurnus anguillicaudatus (CobiUdae) and Hemimyzon sinensis (Homalopteridae) were assigned to the outgroup taxa. Phylogenetic analyses using maximum parsimony (MP), maximum likelihood (ML), and Bayesian retrieved similar topology. Within the Cyprinidae, Leuciscini and Barbini formed the monophyletic lineage respectively with high nodal supports. Leuciscini comprises Xenocyprinae, CuItrinae, East Asian species of Leuciscinae and Danioninae, Gobioninae and Acheilognathinae, and Barbini contains Schizothoracinae, Barbinae, Cyprininae and Labeoninae. Danio rerio, D. myersi and Rasbora trilineata were supposed to separate from Leuciscinae and Barbini and to form another lineage. The positions of some Danioninae species were still unresolved. Analyses of both amino acid variation with parsimony information and two high variation regions indicated that there is no correlation between variations of single amino acid or high variation regions and characteristic size of cyprinids. In addition, the species with smaller size were usually found to be basal within clades in the tree, which might be the results of the adaptation to the primitive ecology and survival pressure.  相似文献   

4.
Cyprinidae is the largest fish family in the world and contains about 210 genera and 2010 species. Appropriate DNA markers must be selected for the phylogenetic analyses of Cyprinidae. In present study, the 1st intron of the S7 ribosomal protein (r-protein) gene is first used to examine the relationships among cyprinid fishes. The length of the 1st intron obtained by PCR amplification ranges from 655 to 859 bp in the 16 cyprinid species investigated, and is 602 bp in Myxocyprinus asiaticus. Out of the alignment of 925 nucleotide sites obtained, the parsimony informative sites are 499 and occupy 54% of the total sites. The results indicate that the 1st intron sequences of the S7 r-protein gene in cyprinids are rich in informative sites and vary remarkably in sequence divergence from 2.3% between close species to 66.6% between distant species. The bootstrap values of the interior nodes in the NJ (neighbor-joining) and MP (most- parsimony) trees based on the present S7 r-protein gene data are higher than those based on cytochrome b and the d-loop region respectively. Therefore, the 1st intron sequences of the S7 r-protein gene in cyprinids are sensitive enough for phylogenetic analyses, and the 1st intron is an appropriate genetic marker for the phylogenetic reconstruction of the taxa in different cyprinid subfamilies. However, attempts to discuss whether the present S7 r-protein gene data can be applied to the phylogeny of the taxa at the level of the family or the higher categories in Cypriniformes need further studies.  相似文献   

5.
Angel-related element belongs to the family of miniature inverted-repeat transposable elements (MITEs). In this paper we report the identification of an Angel- related element in the series Leuciscini of cyprinid fishes, which is located in the second intron of the growth hormone (GH) gene. We have also found that this element is absent in orthologous locus in the series Barbini of cyprinid fishes, that provides new evidence for the monophyly of the series Leuciscini. The insertion of Angel -related element into the GH gene might take place in the common ancestor of the series Leuciscini after its divergence from the series Barbini. The high sequence divergence and relatively broad species distribution of Angel-related elements implies that they might be ancient transposons which appeared about 26 million years ago.  相似文献   

6.
Angel-related element belongs to the family of miniature inverted-repeat transposable elements (MITEs). In this paper we report the identification of an Angel-related element in the series Leuciscini of cyprinid fishes, which is located in the second intron of the growth hormone (GH) gene. We have also found that this element is absent in orthologous locus in the series Barbini of cyprinid fishes, that provides new evidence for the monophyly of the series Leuciscini. The insertion of Angel-related element into the GH gene might take place in the common ancestor of the series Leuciscini after its divergence from the series Barbini. The high sequence divergence and relatively broad species distribution of Angel-related elements implies that they might be ancient transposons which appeared about 26 million years ago.  相似文献   

7.
休闲度假渐渐成为当今社会生活的重要组成部分,东南亚各国独特的景观风格受到各国人民的喜爱。不仅使其成为理想的度假胜地,而且东南亚各国的建筑和景观也在世界各地不断涌现。应运而生的瑞丽弄莫湖湿地公园设计了多个独立又相互联系的子园来分别展现各国的风格。在各子园的主体建筑的设计当中结合各国的异同,从民居中挖掘出代表性元素,充分展现了东南亚各国的景观风格。  相似文献   

8.
针对多仿生机器鱼编队中的对齐行为,利用一致性的方法,提出一种新颖的机器鱼编队控制方法。设定机器鱼群体的一致性协议,模拟一定的群体智能、群体行为,通过机器鱼之间的局部信息交流,群体方向最终达到一致。在机器鱼平台上分别对信息拓扑为无向图和有向图的情况进行了一致性实验验证。实验的初始条件是机器鱼个体的朝向和各自运动方向随机,实验的最后结果两种情况下机器鱼群体方向均达到了一致。实验结果表明,该方法是有效的,实现了编队的对齐行为。  相似文献   

9.
我国古代伟大的思想家、教育家孔子 ,在“诸子蜂起”、“百家争鸣”变革时期 ,高擎起博爱之谓“仁”的旗帜 ,强调“亲亲”、“尊尊”的等级名分 ,提出了“以礼治国”、“重义轻利”等思想 ,几千年来对我国乃至于东亚、东南亚产生了巨大的影响 ,是中国古代优秀传统思想文化的重要组成部分 ,值得深入研究 ,大力弘扬  相似文献   

10.
亚洲期权价格的一个新的多元控制变量估计   总被引:3,自引:0,他引:3  
提出了一个新的用来估计亚洲期权价格的多元控制变量估计,由数值结果可知,当离到期时间很长或标的资产收益的波动率很大的时候它对其他控制变量估计有显著的改进。  相似文献   

11.
探讨米氏凯伦藻培养液(Karenia mikimotoi culture solution,KMCS)及细胞提取物(Cell extracts,KMCE)对胖头鲤(Fathead minnow,FHM)细胞的毒性作用及致死机制。用光学显微镜观察细胞形态变化来分析KMCS和KMCE对FHM细胞的毒性作用,并用CCK法(Cell counting kit)分析KMCS和KMCE对FHM细胞活力的影响;用DNA特异性染料Hoechst 33342检测FHM细胞的细胞核变化,分析KMCS及KMCE是否导致FHM细胞发生程序性死亡及凋亡小体的形成;检测caspase-3的活性,分析KMCS和KMCE是否导致相关凋亡程序的发生。结果发现,用稀释两倍的KMCS和KMCE分别处理FHM细胞4h后,观察到FHM细胞形态均出现明显改变;将未稀释和稀释两倍的KMCS以及稀释两倍的KMCE,分别与FHM细胞孵育,4h后用CCK法检测细胞活性,发现FHM细胞的细胞存活率分别下降了63.6%,22.2%和26.7%。Hoechst 33342染色结果表明,KMCS和KMCE都可以导致FHM细胞中出现凋亡小体,对凋亡相关蛋白因子caspase-3活性的检测,结果显示实验组细胞caspase-3活性水平显著升高,分别为对照组的2.32倍和1.49倍。KMCS和KMCE对鲤鱼FHM细胞生长具有明显的细胞毒性,会导致细胞发生细胞凋亡。  相似文献   

12.
通过对越南植物区系的科和属的组成分析,探讨了越南植物区系的性质与特征。越南植物区系主要由主产热带,分布区扩展到亚热带甚至温带的一些热带性大科组成,在科的分布区类型构成上亦以热带分布科占优势,反映了越南植物区系基本上是热带性质的植物区系,属于热带亚洲植物区系的一部分,但也带有较明显的大陆东南亚热带北缘性质和特点,与热带亚洲核心区植物区系有一定差异。在反映该植物区系的发生特征的代表科的组成上,越南植物区系具有较多的东亚南部植物区系的代表科,在一定程度上反映了其东亚起源背景。在属的地理成分的构成上,越南植物区系典型热带成分占78.9%,若加上越南特有成分,热带成分可占到80%以上,也反映它是热带性质的植物区系。在植物区系分区上属于热带亚洲区系或印度-马来西亚区系,是热带亚洲植物区系的热带北缘类型。  相似文献   

13.
亚式期权与欧式期权的实证比较   总被引:1,自引:0,他引:1  
讨论了用欧式看涨期权和连续情形下的几何平均亚式期权中的看涨期权进行投资时收益和风险之间的关系。从上海和深圳证券交易所随机选取10只股票收盘价的数据进行实证分析,得出采用几何平均亚式期权进行投资比采用欧式期权进行投资风险更小,这与几何平均亚式期权的设计是相符的。  相似文献   

14.
Connective tissue growth factor (CTGF) plays an important role in regulation of cell growth, differentiation, apoptosis and individual development in animals. The study of sequences variation and molecular evolution of CTGF gene across various species of the cyprinid could be helpful for understanding of speciation and gene divergence in this kind of fish. In this study, 19 novel sequences of CTGF gene were obtained from the representative species of the family Cyprinidae using PCR amplification, cloning and sequencing. Phylogenetic relationships of Cyprinidae were reconstructed by neighbor-joining (NJ), maximum parsimony (MP), maximum likelihood (ML) and Bayesian method. Oryzias latipes from the family Cyprinodontidae was assigned to be the outgroup taxon. Leuciscini and Barbini were clustered into the monophyletic lineages, respectively, with the high nodal supports. The estimation of the ratio of non-synonymous to synonymous substitution (dN/dS) for the various branches indicated that there stood the different evolution rates between the Leuciscini and the Barbini. With the ratio of dN/dS of the Leuciscini being lower than that of the Barbini, species within the Barbini were demonstrated to be subjected to the relatively less selection pressure and under the relaxable evolution background. A 6 bp indel (insertion/deletion) was found at the 5' end of CTGF gene of Cyprinidae, and this 6 bp deletion only appeared in the Leuciscini, which is a typical characteristic of the Leuciscini and provides evidence for the monophylogeny of the Leuciscini. For the amino acid sequences of CTGF protein, the most variations and indels were distributed in the signal region and IGFBP region of this protein, implying that these variations were correlated with the regulation of the CTGF gene expression and protein activity.  相似文献   

15.
Connective tissue growth factor (CTGF) plays an important role in regulation of cell growth, differentiation, apoptosis and individual development in animals. The study of sequences variation and molecular evolution of CTGF gene across various species of the cyprinid could be helpful for understanding of speciation and gene divergence in this kind of fish. In this study, 19 novel sequences of CTGF gene were obtained from the representative species of the family Cyprinidae using PCR amplification, cloning and sequencing. Phylogenetic relationships of Cyprinidae were reconstructed by neighbor-joining (NJ), maximum parsimony (MP), maximum likelihood (ML) and Bayesian method. Oryzias latipes from the family Cyprinodontidae was assigned to be the outgroup taxon. Leuciscini and Barbini were clustered into the monophyletic lineages respectively with the high nodal supports. The estimation of the ratio of nonsynonymous to synonymous substitution (dN/dS) for the various branches indicated that there stood the different evolution rates between the Leuciscini and the Barbini. With the ratio of dN/dS of the Leuciscini being lower than that of the Barbini, species within the Barbini were demonstrated to be subjected to the relatively less selection pressure and under the relaxable evolution background. A 6 bp indel (insertion/deletion) was found at the 5' end of CTGF gene of Cyprinidae, and this 6 bp deletion only appeared in the Leuciscini, which is a typical characteristic of the Leuciscini and provides evidence for the monophylogeny of the Leuciscini. For the amino acid sequences of CTGF protein, the most variations and Indels were distributed in the signal region and IGFBP region of this protein, implying that these variations were correlated with the regulation of the CTGF gene expression and protein activity.  相似文献   

16.
本文通过对造成东南亚金融危机原因的考察,论证了东南亚金融危机与“亚洲价值观”的不相关性,指出,以儒家价值观念为核心“亚洲价值观”,不仅在五、六十年代以来东亚经济的快速发展中发挥了重要作用,同时也是东亚国家和地区克服金融危机,重新振兴东亚经济的一个不可忽视的积极文化因素。  相似文献   

17.
鱼肉有着丰富的脂肪酸,尤其是必需脂肪酸,它不仅对鱼类的正常生长和发育有着十分重要的作用,而且对人类的健康也有很重要的作用,但是,由于水体环境的变化,鱼类肌肉脂肪酸组成也会发生改变。文章以拉萨河鱼(裸鲤)脂肪酸组成为样本,同内陆淡水鱼(鲫鱼)的脂肪酸组成进行对比,从而分析脂肪酸组成在不同水体环境下的变化情况。为今后大量养殖营养价值较高的高原鱼类提供依据。  相似文献   

18.
李涛  张春泽  但云峰  赵旭 《科学技术与工程》2022,22(32):14392-14400
鱼类自主游动的模拟问题一直是仿生学、鱼类行为学以及生态水力学等诸多学科共同关注的重要难题。建立一种基于流固耦合数值模拟技术与深度强化学习算法的智慧鱼体自主行为决策平台,可以实现鱼体在不同周围环境条件下以最优决策方案完成游泳任务。该平台采用深度强化学习算法实现鱼脑功能,模拟其不断学习和最终决策;通过浸没边界-Lattice Boltzmann方法对流场及鱼体运动进行实时模拟,可为鱼体提供丰富的训练样本并执行鱼脑决策。基于该平台对鱼类典型捕食运动以及卡门游动进行训练并分析其训练效果。仿真结果表明:在捕食游动问题中,具有不同初始位置偏角的鱼体均能以最优轨迹到达目标点;在卡门游动问题中,鱼体能自主调节尾拍频率,使之接近涡街脱落频率,进而从卡门涡场中吸收能量,以稳定步态在涡街中运动。在鱼类自主游动问题的研究方面,该决策平台较传统物理实验具有更强大的复杂流场适应性,并可为水利工程、生态环境工程等领域的数字孪生提供技术支持。  相似文献   

19.
By using the global atmospheric general circulation model CAM4.0 including an urban canopy parameterization scheme,the possible impacts of large-scale urbanization in East China on East Asian winter monsoon was investigated via idealized numerical experiments.Results suggest that large-scale urbanization can cause a significant warming effect in both surface temperature and air temperature near the surface over most areas of East China.Meanwhile,large-scale urbanization also alters the surface energy balance,causing evident increases in net surface long-wave radiation and sensible heat flux as well as intensified surface thermal heating to the atmosphere.Forced by the surface thermal heating anomalies induced by the large-scale urban expansion,East Asian winter monsoon circulation exhibits distinct changes.Overall,the extensive urbanization over East China will weaken East Asian winter monsoon,but intensify winter monsoon in northeast China.  相似文献   

20.
基于近似对冲的亚式期权定价模型与实证分析   总被引:2,自引:2,他引:0  
考虑了标的股票的价格服从跳-扩散过程的亚式定价问题.利用无套利原理和广义Ito^公式,运用近似对冲跳跃风险的方法,建立了跳-扩散过程中算术平均亚式期权的定价模型.然后,通过变量代换,将超抛物型偏微分方程变为一般抛物型方程,基于半离散化方法,给出了基于半离散化的差分求解方法,并且对差分格式的稳定性和误差进行了分析.最后,以北欧电力交易所曾经交易过的亚式期权为例,对亚式期权定价进行了实证分析.  相似文献   

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