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Allelic variation in a total of 7 microsatellites was examined between elvers of freshwater eels (Anguillajaponica and Anguilla anguilla). The number of alleles at these loci ranged from 8 to 26. A single test of each locus revealed significant deficits of heterozygotes (P〈0.01). Significant departure from expectations of Hardy-Weinberg equilibrium (HWE) was found for all loci within four subpopulations of A. japonica, which opposes the panmixia hypothesis of Schmidt. Also exact tests of population differentiation based on allelic frequency distribution disagree the hypothesis of random distribution of individuals among populations. Population structure among four populations of A. japonica was revealed with FST value of 0.009 8 (P=-0.000 48; 10 000 iteration). Pairwise matrixes of FST and RST showed a significant difference between two distantly related species-A, japonica and A. anguilla. Divergent time of the two species calculated by Goldstein method is over 2 million years. The results may challenge the Schmidt's theory about the distribution of freshwater eels. 相似文献
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A 605 bp section of mitochondrial 16S rRNA gene from Paralichthys olivaceus, Pseudorhombus cinnamomeus, Psetta maxima and Kareius bicoloratus, which represent 3 families of Order Pleuronectiformes was amplified by PCR and sequenced to show the molecular systematics of Pleuronectiformes for comparison with related gene sequences of other 6 flatfish downloaded from GenBank. Phylogenetic analysis based on genetic distance from related gene sequences of 10 flatfish showed that this method was ideal to explore the relationship between species, genera and families. Phylogenetic trees set-up is based on neighbor-joining, maximum parsimony and maximum likelihood methods that accords to the general rule of Pleuronectiformes evolution. But they also resulted in some confusion. Unlike data from morphological characters, P olivaceus clustered with K.bicoloratus, but P cinnamomeus did not cluster with t3. olivaceus, which is worth further studying. 相似文献
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1 INTRODUCTION Pit connection is an important feature in Rhodophyta and significant in algal phylogeny. Various documents have illustrated the existence of pit-connection in red alga previously (Migita, 1967; Ramus 1969a, b; Bourne et al., 1970; Lee and F… 相似文献
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Morphogenetic Processes in Division of Uronemella filificum (Ciliophora, Scuticociliatida) 总被引:2,自引:0,他引:2
MAHongwei SONGWeibo MAHonggang 《青岛海洋大学学报(英文版)》2002,1(2):140-144
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2.大禹疏壶口
壶口瀑布,是黄河干流中最壮观的瀑布,它以平均1000个流量(立方米/秒)的速度,从30多米的高处在这宽仅20多米的峡口中倾泻而下,激起50米高的水花,飞出彩虹,浪沫漂到下游100-200米岸上,给游人身上增添点点泥沫。 相似文献
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秦健秋 《成都信息工程学院学报》2007,22(6):750-753
设k∈N,f(z)为复平面上的超越亚纯函数,φ(z)、ak-1(z),…,a0(z)为f(z)的小函数,且φ(z)≠0.置P(f)(z)=f^(k)(z)+ak-1(z),f^(k-1)(z)+…+a1(z)f(z)+a0,(z),且P(f)(z)不恒为常数.当k≤4时,满足Nr)(r,1/f)=S(r,f);k≥5,满足N4)(r,1/f)=S(r,f),则T(r,f)〈20N^-(r,1/φfP-1)+s(r,f). 相似文献
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基因间隔序列(ITS)在水产动物种质鉴定和遗传多样性分析中的应用 总被引:1,自引:0,他引:1
近年来,由于国内外市场对水产品的需求不断增长,水产业因此获得了长足的发展,许多水产种类的养殖量有了大幅度的增加,在给我国国民经济的增长作出贡献的同时,已经不可避免的带来了许多弊端,一些方面甚至在一定程度上会影响未来水产业的发展。其中最应该引起关注的是由于目前捕捞强度的增加、生态环境的恶化等,导致许多种群的数量大量减少,产量也随之降低,种质资源遭到前所未有的破坏和衰退。因此,种质鉴定、种群分析及保护和遗传多样性的研究已经成为当前水产研究的当务之急。 相似文献
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TANG Xiaoqian ZHOU Li ZHAN Wenbin 《青岛海洋大学学报(英文版)》2008,(3):343-351
Studies were conducted to determine the cause of the acute mortality of half-smooth tongue sole Cynoglossus semilaevis Günther juveniles in a fish farm in Jimo, Shandong Province, China, in June 2006. Gross signs of the diseased tongue sole included several petechiae and ecchymoses on the body and fin necrosis and hemorrhagic lesion at the base of the fin. Bacteria were isolated from kidney, liver and hemorrhagic lesions of the diseased tongue sole. Among 14 strains, SJ060621 was proved to be highly virulent to juvenile tongue sole with LD50 value of 〈1.0×10^5 colony forming units (CFU)mL^-1, while the remaining 13 were avirulent. Among the 16 antibiotics tested, SJ060621 was sensitive to gentamicin and nitrofurantoin. It was identified as Listonella anguillantm with conventional plate and tube tests in combination with API 20E analysis. 16S rRNA gene and partial HSP60 gene sequenceing analysis revealed that the strain was highly homologous with L. anguillarum. Examination of the infected musculature by electron microscopy indicated numerous bacteria and lots of macrophages containing phagocytosed bacteria. Histopathological investigations revealed severe necrotic degenerative changes in the infected organs. Indirect immunofluorescence assay (IFA) was employed to detect the location of occurrence of bacteria, and bacteria were found in aggregations in the inflammatory areas in musculature. 相似文献
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张庆德 《成都信息工程学院学报》1995,(3)
设f(z)为复平面上的超越亚纯函数,不具有形式Cexp(-Bz/A),其中A、B及C为复数,则T(r,f)可被f(z)的极点计数函数及Af(z)f'(z)+Bf ̄2(z)的a计数函数(a≠0)所控制。 相似文献
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东方刚现出鱼肚白,便听到砰砰的敲门声。“准是訾鸣又来啦!”高翔满有把握地说。“您俩光腚就在一块,后来又同窗八九年,人恁熟,咋会猜不着?”妻子表示赞同。其实,訾鸣昨晚10点从这儿才走。原因是高翔冒着生命危险,把其溺水的独生儿子救了出来,自己反倒被水呛得呕吐,以致吃药打针。对此,他感激不尽,放心不下。“翔哥,气喘咋样?”他未进门就问。“上午的事,下午就好了,为这,让你跑几趟。要是你碰上孩子落水,也一定会救!”高翔对所谓“舍己救人”淡然置之,不当回事,没觉察到訾鸣内心充满歉疚。他们两个人同村、同学,又同在乡政府工作。高翔管理… 相似文献