Molecular Phylogeny of Geographical Isolates of Bursaphelenchus xylophilus: Implications on the Origin and Spread of this Species in China and Worldwide

The genetic diversity and phylogeny of 26 isolates of Bursaphelenchus xlophilus from China, Japan, Portugal and North America were investigated based on the D2/3 domain of 28S rDNA, nuclear ribosomal Internal Transcribed Spacer (ITS) sequences, and random amplified polymorphic DNA (RAPD) analysis. The genetic diversity analysis showed that the D2/3 domain of 28S rDNA of isolates of B. xlophilus from China, Portugal, Japan and the US were identical and differed at one to three nucleotides compared to those from Canada. ITS sequences of isolates from China and Portugal were the same; they differed at one or two nucleotides compared to those of Japanese isolates and at four and 23 nucleotides compared to those front the US and Canada, respectively. The phylogenetic analysis indicated that Chinese isolates share a common ancestor with one of the two Japanese clades and that the Canadian isolates form a sister group of the clade comprised of isolates from China, Portugal,Japan, and the US. The relationship between Japanese isolates and those from China was closer than with the American isolates. The Canadian isolates were the basal group of B. xylophilus. This suggests that B. xlophilus originated in North America and that the B. xylphilus that occurs in China could have been first introduced from Japan. Further analysis based on RAPD analysis revealed that the relationship among isolates from Guangdong, Zhejiang, Shandong, Anhui provinces and Nanjing was the closest, which suggests that pine wilt disease in these Chinese locales was probably dispersed from Nanjing, where this disease first occurred in China.

B itte r an d Sw e e t /Um am i Ta s te Re c ep to rs w ith D iffe ren tly Evo lu tio n a ry Pa thw ays

通过生物信息学和系统发育学分析,研究了苦味受体和甜味/鲜味受体的进化途径。结果显示,苦味受体 和甜味/鲜味受体在进化上具有远相关,并且具有不同的进化途径,提示这可能是导致这些受体具有不同功能,传 导不同味觉的原因。

大银鱼和小齿日本银鱼线粒体细胞色素b 和16S rRNA基因部分序列分析

　对大银鱼和小齿日本银鱼的线粒体细胞色素b 和16S rRNA 基因片段进行了扩增和序列测定,分析比较了2 种 间的序列差异。大银鱼2 个个体间细胞色素b 基因序列无差异,小齿日本银鱼3 个个体的序列出现了2 种单倍型;大银鱼 同小齿日本银鱼细胞色素b 序列(单倍型SB21) 之间存在86 个碱基差异(差异率21 %) ,变异较大。大银鱼、小齿日本银鱼 的16S rRNA 基因片段种内个体间无序列差异,两种间存在21 个碱基的差异(差异率5 %) ,有1 个碱基的插入/ 缺失。由 此可见,2 种银鱼间线粒体细胞色素b 基因的进化速率较快,约为16S rRNA 基因片段的4 倍。根据细胞色素b 序列数据, 推算出2 种银鱼大概在中新世晚期发生分化。

养殖褐牙鲆细胞色素b 基因序列的初步研究

对养殖褐牙鲆( Paralichthys olivaceus) 的线粒体DNA Cytb 基因的部分序列进行测定,测得的目的DNA 片段的长 度为410 bp ,其A(104 bp) 、T(119 bp) 、C(117 bp) 、G(70 bp) 4 种碱基平均含量分别为25. 4 %、29. 0 %、28. 5 %、17. 1 %。 在28 个褐牙鲆个体中共出现了3 种单倍型。白化褐牙鲆出现的第1 种和第3 种单倍型个体数分别为10 尾(占白 化褐牙鲆样本数的90. 91 %) 和1 尾(9. 09 %) ;6 尾黑化褐牙鲆均出现第1 种单倍型(100 %) ;正常褐牙鲆出现的3 种 单倍型尾数分别为7 尾(占正常褐牙鲆样本数的55. 56 %) 、2 尾(22. 22 %) 和2 尾(22. 22 %) ;测得的序列与既知序列 间在第6 bp 、第19 bp 和第402 bp 碱基处出现差异。由于褐牙鲆Cytb 基因的高度同源性,研究其白化、黑化和正常 状态时出现的序列差异,对于寻找褐牙鲆白化机理研究的分子标记意义重大。

六种鱼巴亚科鱼类线粒体细胞色素b 基因序列分析

测定了鱼巴亚科云南光唇鱼( Acrossocheilus yunnanensis) 、宽头四须鱼巴( Barbodes laticeps) 、抚仙金线鱼巴 ( Sinocyclocheilus tingi) 和滇池金线鱼巴( Sinocyclocheilus grahami) 4 种鱼类线粒体细胞色素b 基因DNA 序列402 bp ,结合已知的云南倒刺鱼巴( S pinibarb denticulatus yunnanensis) 和细尾长臀鱼巴( Mystacoleucus lepturus) 的同源 序列,组成1 个6 种代表鱼巴亚科5 属鱼类的数据集. 选用已知的云南鲴( Xenocypris yunnanensis) 作为外群,采用 邻接法、最大简约法和最大似然法构建了分子系统树. 结果显示: 倒刺鱼巴属( S pinibarbus) 和光唇鱼属 ( Acrossocheilus) 有较近的亲缘关系,四须鱼巴属( Barbodes) 和长臀鱼巴属( Mystacoleucus) 有较近的亲缘关系,而金 线鱼巴属( Sinocyclocheilus) 和它们的关系不能确定. 上述结果与它们的地理分布基本吻合.

Study on Mitochondrial DNA Cytochrome b Gene of Chinese sea bass, Lateolabrax sp.

参考鳗鲡等鱼类线粒体 DNA序列进行了中国花鲈线粒体 DNA细胞色素 b基因片断的引物设计、PCR扩增及其序列测定。得到中国花鲈的碱基序列为 4 10 bp,其 A、T、G、C含量分别为 10 1bp(2 4 .6 3% )、112 bp(2 7.32 % )、72 bp(17.56 % )、12 5bp(30 .4 9% ) ,与鳗鲡等其他鱼类相同基因片断序列碱基含量相似。

从线粒体细胞色素b探讨长臀ba属三个种分类与进化的关系

细尾长臀ba与月斑长臀ba、长臀ba间存在遗传分化,分化程度与鲤科其它鱼类相似;而月斑长臀ba和长臀ba却无法分开。结果提示,月斑长臀ba和长臀ba很可能为同一个种。此外,长臀ba属与云南倒刺ba的亲缘关系较近,表明有争议的长臀ba属归入ba亚科是合理的。

犬科的线粒体细胞色素b DNA序列及其分子系统学研究

通过对犬科的赤狐、蓝狐、貉和狼4种的线粒体细胞色素b约372bp DNA片段序列分析,结合GenBank中狗、西门豺和非洲野犬3种的该区段DNA序列的比较,共发现113个核苷酸位点存在变异(约30%)。NJ法构建的分子系统树显示,非洲野犬最先从犬科动物中分化出来;犬属的狼、狗和西门豺等3种为系统树上独立的一支,且其分歧的时间较赤狐、蓝狐和貉早;赤狐和蓝狐具有较近的亲缘关系。

蜂猴线粒体细胞色素b基因变异特点及系统发育分析

在所研究的个体中,2个蜂猴物种碱基组成具有哺乳动物的共同特点,它们之间转换比(特别是密码子第3位)是颠换比的6倍多,大于其他种间比较;低的Ka/Ks值(<0.1)说明懒猴科cyt-b基因的异义突变位点受到强的选择压力作用。由cyt-b基因构建的系统发育树符合懒猴科化石记录和形态学分类观点。根据化石记录和分化时间有一定线性关系的第3位颠换和同义突变速率,估算蜂猴与倭蜂猴种间、蜂猴与瘠蜂猴属间可能的分化时间分别为300和600万年。

蝮亚科蛇线粒体细胞色素b基因序列分析及其系统发育

竹叶青蛇在全部受试物种中处于原始地位,分布于东北地区的蛇岛蝮、乌苏里蝮、黑眉蝮与浙江和陕西产的短尾蝮所组成的分枝与横断山区的高原蝮、雪山蝮聚集形成的分枝组成姐妹群,支持分布于中国境内的亚洲蝮属蛇种的两个起源及分化地的假说,同时探讨了蝮蛇的分类地位问题。

中国花鲈细胞色素b基因片断的序列研究

参考鳗鲡等鱼类线粒体DNA序列进行了中国花鲈线粒体DNA细胞色素b基因片断的引物设计、PCR扩增及其序列测定。得到中国花鲈的碱基序列为410bp，其A、T、G、C含量分别为101bp（24.63%）、112bp（27.32%）、72bp（17.56%）、125bp（30.49%），与鳗鲡等其他鱼类相同基因片断序列碱基含量相似。

细胞色素b基因序列与11种熊蜂的系统进化

通过比较一段357bp的细胞色素b的序列,分析了熊蜂属5亚属11种熊蜂系统发育关系。5亚属包括Bombus(5种)、Thoracobombus(3种)、Mendacibombus(1种)、Fervidobombus(1种)和Pyrobombus(1种)。该序列有65个单变异多态位点和71个简约信息多态位点,翻译成119个氨基酸序列后有45个氨基酸变异位点。根据P-距离构建的邻接树(NJ tree)和最大简约树(MP tree)都显示同样的结果:Mendacibombus(B. avinovielllus)分化最早;Fervidobombus(B. pensylvanicus)次之;Pyrobombus(B. impatiens)和Bombus形成姊妹群;Bombus亚属是单系群,其中B. ignitus在所研究的5个种中分化最早。

zhao科鱼类细胞色素b基因片段的序列测定及其系统发育的初步研究

从9种zhao科鱼类的福尔马林标本中获得了333bp的细胞色素b基因片段的序列。经MUST软件排序后,有101个变异位点,其中有39个信息位点。序列在成对物种间的距离为8-48。平均遗传距离为2.4%-14.4%。简约分析产生了最大简约系统树,Bagarius是最原始的属,并与所有其他的物种形成姊妹群。其余8个属形成一个单系类群并分为二个姊妹群,而鳗zhao鱼类并未形成一个单系类群。

Mitochondrial cytochrome b gene sequences of Old World monkeys: With special reference on evolution of Asian colobines

The classification and phylogenetic relationships of the Old World monkeys are still controversial. For Asian colobines, from three to nine genera were recognized by different primatologists. In the present study, we have sequenced a 424 bp mitochondrial tRNA(Thr) gene and cytochrome b gene fragment from Macaca mulatta, Mandrillus sphinx, Mandrillus leucophaeus, Semnopithecus entellus, Trachypithecus vetulus, T. johnii, T. phayrei, T. francoisi, Pygathrix nemaeus, Rhinopithecus roxellanae, R. bieti, R. avunculus, Nasalis larvatus, and Colobus polykomos in order to gain independent information on the classification and phylogenetic relationships of those species. Phylogenetic trees were constructed with parsimony analysis by weighting transversions 5 or 10 fold greater than transitions. Our results support the following conclusions: (1) the Old World monkeys are divided into two subfamilies; (2) that among the colobines, Colobus, the African group, diverged first, and Nasalis and Rhinopithecus form a sister clade to Pygathrix; (3) that there are two clades within leaf monkeys, i.e. 1) S. entellus, T. johnii, and T. vetulus, and 2) T, phayrei and T. francoisi; (4) that Rhinopithecus avunculus, R. roxellanae, and R. bieti are closely related to each other, and they should be placed into the same subgenus; (5) that Rhinopithecus is a distinct genus; and (6) that the ancestors of Asian colobines migrated from Africa to Asia during the late Pliocene or early Pleistocene.

Mitochondrial cytochrome b sequences variation of Protura and molecular systematics of Apterygota

Mitochondrial cytochrome b genes of about 450 bp fragments from 3 proturan species, 5 collembolan species and 2 dipluran species have been sequenced. The number of nucleotide substitutions and Kimura 2-parameter distances have also been calculated, and a series of molecular phylogenetic trees reconstructed by using parsimony and distance methods. The proturan, collembolan and dipluran species have evolved monophyletic groups. The results suggest that Protura and Collembola are sister groups, while Diplura is more or less demonstrating a closer phylogenetic relationship to the pterygotan insects. The phylogeny and their systematic position of protura and other groups are also discussed.