941 resultados para 12S rRNA
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对蝮亚科(蛇岛蝮Gloydius shedaoensis Zhao、黑眉蝮Gloydius saxatilis Emelianov、乌苏里蝮Gloydius ussurriensis Emelianov、竹叶青Trimeresurus stejnegeri Schmidt和分别来自不同地区的尖吻蝮Deinagkistrodon acutus Guenther、短尾蝮Gloydius brevicaudus Stejneger各两条)6种蛇共8个个体测定、分析了约370bp线粒体12S rRNA基因序列,以游蛇科链蛇属半棱鳞链蛇Dinodon semicarinatus序列为外群构建分子系统树。
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东方鲀属鱼类是一个区域性分布类群,该属目前包括22个有效种,主要分布区域从日本海西部到中国沿海.本研究通过联合17种(21尾)东方鲀属鱼类的细胞色素b(1137bp)和12SrRNA(952bp)基因全序列研究了东方鲀属鱼类的系统发育关系.采用了邻接法(NJ)、最大简约法(MP)、最大似然法(ML)和Baysian方法构建了分子系统树.结果表明:(ⅰ)东方鲀属鱼类为一单系类群;(ⅱ)基于分子系统发育分析,东方鲀属鱼类可划分为6个亚群;(ⅲ)在分子水平上,本属各鱼类物种的遗传距离比较接近,这显示了其物种间分
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通过对鲤形目鱼类 5个科的代表类群的完整线粒体 12SrRNA进行测序和分析 ,以检验目前的形态学假说。经序列比对后 ,有 10 0 0个位点 ,其中 467个位点在茎区 ,53 3个在环区 ;有 3 95个位点为变化位点 ,其中 2 67个为系统发育信息位点。采用邻接法和最大简约法进行了系统发育分析 ,其结果支持鲤科鱼类成为一个单系群 ,非鲤科的鲤形目鱼类成为另一个单系群的观点 ,这与Siebert提出的假说相一致。鲤科鱼类包含 3个主要的分支 ,即鱼丹系、鲤系和雅罗鱼系 ;但在非鲤科鲤形目鱼类中 ,其
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A molecular approach was developed to distinguish species of red snappers among commercial salted fish products. The specific fragments of the mitocliondrial 12S rRNA gene, which were about 450 bp, were obtained using the semi-nested polymerase chain reaction (semi-nested PCR). Subsequently, PCR amplicons were sequenced, aiming to select restriction endonucleases that generated species-specific restriction fragment length polymorphism (RFLP) profiles. Discrimination of red snappers Lutjanus sanguineus, L. erythopterus from L. argentintaculatus, L. malabarius and other morphologically similar fishes such as Lethrinus leutjanus and Pinjalo pinjalo was feasible by one restriction digestion reaction with three endonucleases Hae III, Sca I and SnaB I, however, for differentiation of L. sattguineus and L. erythopterus, another restriction digestion reaction with single restriction endonuclease Mae II was needed. The seminested PCR-RFLP was demonstrated to be reliable in species identification of salted fish products in this study. (c) 2005 Published by Elsevier Ltd.
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A molecular approach was developed to distinguish species of red snappers among commercial salted fish products. The specific fragments of the mitochondrial 12S rRNA gene, which were about 450bp, were obtained using the semi-nested polymerase chain reaction (semi-nested PCR). Subsequently, PCR arnplicons were sequenced, aiming to select restriction endonucleases that generated species-specific restriction fragment length polymorphism (RFLP) profiles. Discrimination of red snappers Lutjanus sanguineus, Lutjanus erythopterus from Lutjanus argentimaculatus, Lutjanus malabarius and other morphologically similar fishes such as Lethrinus leutjanus and Pinjalo pinjalo was feasible by one restriction digestion reaction with three endonucleases Hae III, Sca I and SnaB I, however, for discrimination of L. sanguineus and L. erythopterus, another restriction digestion reaction with single restriction endonuclease Mae II was needed. The semi-nested PCR-RFLP was demonstrated to be reliable in species identification of salted fish products in this study. (c) 2005 Elsevier Ltd. All rights reserved.
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Biogenesis of mammalian mitochondrial ribosomes requires a concerted maturation of both the small (SSU) and large subunit (LSU). We demonstrate here that the m(5)C methyltransferase NSUN4, which forms a complex with MTERF4, is essential in mitochondrial ribosomal biogenesis as mitochondrial translation is abolished in conditional Nsun4 mouse knockouts. Deep sequencing of bisulfite-treated RNA shows that NSUN4 methylates cytosine 911 in 12S rRNA (m5C911) of the SSU. Surprisingly, NSUN4 does not need MTERF4 to generate this modification. Instead, the NSUN4/MTERF4 complex is required to assemble the SSU and LSU to form a monosome. NSUN4 is thus a dual function protein, which on the one hand is needed for 12S rRNA methylation and, on the other hand interacts with MTERF4 to facilitate monosome assembly. The presented data suggest that NSUN4 has a key role in controlling a final step in ribosome biogenesis to ensure that only the mature SSU and LSU are assembled.
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马来熊在 IUCN 红皮书中被列为受胁动物, 其保护受到广泛的关注. 该文研究4只马来熊的线粒体 DNA 序列, 其中1只来自云南, 其余3只产地不详, 但来自不同的搜集渠道. 对于每个个体, 作者测定了 397bp 的细胞色素b基因、346bp 的12S rRNA基因、98bp 的 tRNA 基因和333bp 的D环区序列, 共计1174bp. 经与黑犀牛序列比较, 发现 RNA 基因的空间结构对基因的进化有显著影响, 环区的进化明显快于茎区的. 对于细胞色素b基因、12S rRNA基因和 tRNA 基因, 在马来熊个体间未发现序列变异. 这一结果提示, 马来熊群体的遗传变异程度低. 在D环区, 有13和1个位点分别出现转换和颠换. 根据D环区序列, 作者采用简约法确定了马来熊群体间的进化关系. 作者的结果表明, 线粒体 DNA 的D环区是研究马来熊群体遗传结构十分有效的遗传结构十分有效的遗传标记。
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We investigated the phylogenetic relationships among most Chinese species of lizards in the genus Phrynocephalus (118 individuals, collected from 56 populations of 14 well-defined species and several unidentified specimens) using four mitochondrial gene fragments (12S rRNA, 16S rRNA, cytochrome b, and ND4-tRNA(LEU)). The partition-homogeneity tests indicated that the combined dataset was homogeneous, and maximum-parsimony (MP), neighbor-joining (NJ), maximum-likelihood (ML) and Bayesian (BI) analyses were performed on this combined dataset (49 haplotypes including outgroups for 2058 bp in total). The maximum-parsimony analysis resulted in 24 equally parsimonious trees, and their strict consensus tree shows that there are two major clades representing the Chinese Phrynocephalus species: the viviparous group (Clade A) and the oviparous group (Clade B). The trees derived from Bayesian, ML. and NJ analyses were topologically identical to the MP analysis except for the position of P. mystaceus. All analyses left the nodes for the oviparous group, the most basal clade within the oviparous group, and P. mystaceus unresolved. The phylogenies further suggest that the monophyly of the viviparous species may have resulted from vicariance, while recent dispersal may have been important in generating the pattern of variation among the oviparous species. (C) 2003 Elsevier Science (USA). All rights reserved.
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Mutation C1494T in mitochondrial 12S rRNA gene was recently reported in two large Chinese families with aminoglycoside-induced and nonsyndromic hearing loss (AINHL) and was claimed to be pathogenic. This mutation, however, was first reported in a sample f
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Phylogenetic relationships among representative species of the subfamily Raninae were investigated using approximately 2000 base pairs of DNA sequences from two mitochondrial (12S rRNA, 16S rRNA) and two nuclear (tyrosinase, rhodopsin) genes. Phylogenetic
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The phylogeny of representative species of Chinese ranids was reconstructed using two nuclear (tyrosinase and rhodopsin) and two mitochondrial (12S rRNA, 16S rRNA) DNA fragments. Maximum parsimony, Bayesian, and maximum likelihood analyses were employed.-
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Phylogenetic relationships among representative species of the family Rhacophoridae were investigated based on 2904 bp of sequences from both mitochondrial (12S rRNA, 16S rRNA, the complete t-RNA for valine), and nuclear (tyrosinase, rhodopsin) genes. Max
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Phylogenetic relationships and systematics of the eight currently recognized species of the genus Bombina were investigated using four mitochondrial gene fragments (16S rRNA, 12S rRNA, ND4-tRNA(LEU), and cytochrome b). We prepared two different concatenat
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The phylogenetic relationships among rhacophorid frogs are under dispute. We use partial sequences of three mitochondrial (12S rRNA, 16S rRNA, and cytochrome b) and three nuclear protein-coding (Rag-1 rhodopsin exon 1, and tyrosinase exon 1) genes from 57
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鸟类分类是鸟类学其他研究领域的基础,近年来分子技术的发展,以及计算机技术的应用为鸟类分类学和鸟类系统演化研究提供了新的研究手段,给传统的系统分类研究带来了新的机遇.Tautz等于2002年首先提出运用DNA序列作为生物分类系统的主要平台,即DNA分类学(DNA Taxonomy).而Hebert等于2003年则首次提出了DNA条形码(DNA Barcoding)的概念,并对其物种分类和鉴定意义予以肯定,建议利用线粒体细胞色素C氧化酶亚单位Ⅰ(COI)的特定区段来做DNA条形编码的基础.在鸟类DNA分类方面,国内学者应用线粒体基因Cut b,COI,c-mos,c-myc,12s rRNA,16s rRNA,ND2,ND3,CR,RAG-1以及核基因myoglobin introⅡ等不同片段对很多类群进行了分类探讨和系统发育研究.但是主要集中在鸡形目及雀形目鸟类.中国是鸟类多样性极其丰富的国家,近年来很多亚种、种及以上分类阶元依然存在问题,因此,中国鸟类物种的分类地位、系统发育与演化关系等依然有很多问题等待深入研究.目前国内基于COI的鸟类分类及系统发育研究有了一些报道,但是真正的DNA条形码工作尚需继续、深入地开展.