基于DNA条形码的广西苦瓜中实蝇幼虫分子鉴定研究*

实蝇是多种热带、亚热带水果和蔬菜的重要害虫,其卵、幼虫、蛹难以通过形态特征进行种类鉴定。DNA条形码是近年来出现的物种分子鉴定技术,能够实现对昆虫非成熟虫态的快速鉴定。本研究利用DNA条形码技术和BOLD系统,选取线粒体DNA细胞色素氧化酶I（COI）基因片段,针对采自于广西南宁地区苦瓜中的实蝇幼虫样品进行了序列测定、比对和分析。结果显示,在所检测的10头实蝇幼虫样品中,有4头为瓜实蝇［Bactrocera cucurbitae (Coquillett)］、6头为南亚果实蝇［Bactrocera tau (Walker)］。     

白洋淀流域宽鳍鱲遗传多样性及种群历史动态

基于线粒体Cytb和COI基因联合,对白洋淀流域沙河和拒马河宽鳍鱲种群遗传多样性及种群历史动态分析。结果表明：141个样本中检测出45个单倍型,种群间共享单倍型有2个。拒马河种群的单倍型多样性与核苷酸多样性(h=0.7120,π=0.01182)均高于沙河种群(h=0.4514,π=0.00313)。AMOVA分子方差分析、种群间遗传分化指数(FST)及系统发育树均表明2个种群间未出现明显分化,种群内变异(96.43%)大于种群间变异,种群之间存在较大的基因流(6.745)。中性检验、错配分析显示沙河种群和拒马河种群未经历过种群扩张,贝叶斯天际线点图显示沙河种群保持稳定,拒马河种群在0.004Ma前经历了种群扩张。白洋淀流域宽鳍鱲有效种群在0.175~0.125Ma前经历种群扩张,后维持稳定。结合单倍型网格图及系统发育树分析,沙河种群经历过奠基者效应。参考鲤科鱼类Cytb基因0.84%~1%/Ma的进化速率,2个地理种群的分歧时间为0.089~0.067Ma前。     

基于COI基因的橡胶树六点始叶螨遗传多样性分析

六点始叶螨是橡胶树上的重要害螨之一,具有分布范围广、危害重等特点。为了研究其遗传多样性和遗传分化,本研究利用线粒体COI（mitochondrial cytochrome oxidase subunit I）基因序列对采自海南、云南、越南河内等地区橡胶树上的11个不同地理种群的165头样本进行了种群的遗传多样性分析。获得的六点始叶螨线粒体COI基因片段长度均为658 bp,分析发现可变位点30个,其中简约信息点15个,单变异位点15个,单倍型15种;种群间F_ST值为0.34698,Nm值为0.47,G_ST值为0.19660,表明11个种群的六点始叶螨存在一定的遗传分化。     

Morphological and molecular diversity at a regional scale: A step closer to understanding Antarctic nematode biogeography

Antarctica is one of the harshest environments on earth and yet life has managed to persist on the continent for millions of years. While most of the continent is covered by snow and ice, in some coastal and mountain regions that do not have permanent cover terrestrial invertebrate fauna dominate. Nematodes are one of the most common taxa present in these environments, but despite their abundance very little work on diversity and distribution has been performed for the Phylum across the Antarctic continent. We examined nematodes from 123 limno-terrestrial samples from the vicinity of the Australian Antarctic Stations (62.8°E–110.5°E) using the mitochondrial cytochrome c oxidase subunit I (COI) gene, and morphological analyses. We identified the nematodes Plectus murrayi, Pl.cf. frigophilus, Scottnema cf. lindsayae, Halomonhystera cf. halophila, H. cf. continentalis and Eudorylaimus spp. The distribution of these species appears to be determined by habitat type and salinity. We also made comparisons using the COI gene with nematodes from localised sampling from Dronning Maud Land, Francis Island (Antarctic Peninsula), and Tierra del Fuego (TF), and also with COI sequences from other worldwide locations. Contrasting levels of COI sequence divergence were identified among genera and species, ranging from low levels for Pl. murrayi (≤0.5%), medium levels for S. cf. lindsayae (≤2.1%) and Halomonhystera (≤4.3%), and high within Pl.cf. frigophilus (≤8.4%). Distribution ranges varied according to the species, with widespread ranges within Antarctica for Pl. murrayi and Scottnema cf. lindsayae (a range of over 2000 km); and distribution beyond Antarctica to TF for Pl.cf. frigophilus. Our results reveal the presence of cryptic species even when conservative approaches are applied in species delimitation.     

新疆普氏野马马胃蝇蛆病主要病原体黑腹胃蝇溯源

马胃蝇蛆病在中国新疆地区马科动物中广泛流行，其中的病原体———黑腹胃蝇的感染比例最高。对该地区感染普氏野马、蒙古野驴和当地家马的黑腹胃蝇195条线粒体 COI 基因序列进行分析，得到了57个单倍型；采用邻接法(NJ)构建单倍型之间的系统发育树显示存在6个遗传分化程度较大的簇。结果表明：1)感染3种宿主的黑腹胃蝇单倍型多样性均很高，说明感染同一宿主个体的黑腹胃蝇来自多个母本；2)感染3种宿主的黑腹胃蝇遗传分化程度较低，其中感染野马和野驴的黑腹胃蝇群体基因交流最频繁，说明放归普氏野马种群每年重复感染的黑腹胃蝇主要源自同域野驴；3)当地黑腹胃蝇传播期较为滞后，其传播盛期发生在家马离开以后。     

越南火龙果中杰克贝尔氏粉蚧的检疫鉴定

福建出入境检验检疫局多次从越南进口的火龙果中截获粉蚧活虫,为了快速、准确的鉴定到种,选用通用引物LCO1490/HCO2198扩增该虫的COI序列,得到698 bp的基因片段,与Gen Bank和BOLD Systems v3系统中已发布的DNA序列进行比对,初步确定种类后,再查阅文献资料,利用形态学进行复核,最终确定该粉蚧为杰克贝尔氏粉蚧(Pseudococcus jackbeardsleyi GimpelMiller)。     

A shot in the dark for conservation: Evidence of illegal commerce in endemic and threatened species of elasmobranch at a public fish market in southern Brazil

1. The illegal sale of endangered elasmobranchs has been recorded in a number of different Brazilian states, where sharks and rays are being marketed primarily as ‘cação’ or ‘viola’. Brazil is ranked among the top 10 nations worldwide that harvest most sharks, causing an immeasurable impact on the local elasmobranch populations.
2. The present study applied the DNA barcoding technique, based on the cytochrome C oxidase subunit I gene, for the molecular identification of the elasmobranch species sold as processed products under the generic names of ‘cação’, ‘mangona’, ‘azul’, ‘cambeva’, ‘fiuso’ and ‘lombo preto’, in the fish market of the city of Florianópolis, capital of the state of Santa Catarina, Brazil.
3. Nine elasmobranch species were identified in the 56 samples analysed, including six sharks and three rays, representing six families, the Carcharhinidae, Sphyrnidae, Squatinidae, Arhynchobatidae, Myliobatidae and Gymnuridae. Prionace glauca, identified in more than half (56%) of the samples analysed, is listed as Near Threatened by the International Union for the Conservation of Nature.
4. Six species identified in the present study, Sphyrna zygaena, Sphyrna lewini, Squatina guggenheim, Carcharhinus signatus, Gymnura altavela and Rioraja agassizii, are under some level of risk of extinction, while two others (Rhizoprionodon lalandii and Myliobatis goodei) are listed as Data Deficient.
5. Our results indicate that the commercial exploitation of endemic sharks and rays at risk of extinction is commonplace in southern Brazil. This reinforces the need for more systematic monitoring of the trade in fishery products and more effective application of the environmental legislation and conservation programmes.

     

三个群体罗氏沼虾线粒体COI基因的遗传多样性分析

运用PCR方法,扩增罗氏沼虾缅甸原种F1代、广西选育群体和江苏养殖群体的线粒体DNA上的细胞色素氧化酶(Cytochrome oxidase subunit I,COI)基因,在此基础上选用10种限制性内切酶对扩增产物进行限制性片段长度多态(RFLP)分析。三个群体共发现2个多态位点,11种酶切图谱,3种基因型。三群体的多态座位比例、平均杂合度和基因型多样性指数分别为:缅甸原种F122.2%、0.0556、0.0472,广西选育群体22.2%、0.0400、0.0398,江苏养殖群体11.1%、0.0106和0.0083,群体间遗传差异未见显著。根据群体间遗传距离构建UPGMA聚类关系图,显示广西选育群体和江苏养殖群体间的遗传关系较近,而与原种F1群体的遗传关系较远。     

中国文昌鱼系统分类的线粒体COI和cytb基因片段分析

白氏文昌鱼Branchiostoma belcheri(Gray)在我国和日本沿海均有分布,一般认为分布于青岛和日本沿海的文昌鱼为白氏文昌鱼的一个亚种(B.belcheri tsingtauense),分布于厦门地区的文昌鱼为白氏文昌鱼。该文测定了厦门海域和青岛海域的文昌鱼mtDNA COI和Cyt b基因的部分序列,并与日本产的文昌鱼以及产于大西洋的几种文昌鱼进行了比较。基于COI和Cyt b基因序列的分析结果表明,厦门文昌鱼和青岛文昌鱼之间的平均遗传距离是18.8%和20.3%,远远超过了在其他物种中观察到的种内差异,已达到种间差异水平,而日本文昌鱼和青岛文昌鱼的遗传距离分别为1.3%和0.9%,应属于种内差异。该文研究结果支持厦门文昌鱼和青岛文昌鱼为不同种的观点。     

高通量测序分析5例进口鱼粉鱼源性成分构成

为揭示鱼粉原料构成,保证鱼粉质量,本研究应用高通量测序技术对来源于不同国家的5例进口鱼粉样品进行测序,并基于COI基因及其丰度对鱼粉鱼源性成分构成进行分析。提取鱼粉样品DNA后应用鱼类通用COI基因扩增引物进行PCR扩增,得到鱼类混合COI基因序列产物,将扩增产物送测序公司进行高通量测序,将COI基因测序数据与鱼类相关数据库进行比对,通过比对结果进行鱼粉的物种源性成分分析。结果显示,成功获得了5例鱼粉样品中原料鱼成分,其中白鱼粉原料鱼主要成分为鳕鱼;而红鱼粉原料鱼成分较为多样,涉及鲱鱼、竹刀鱼等。通过Python对数据进行统计分析,绘制PCR扩增后鱼类COI基因丰度图,进一步直观提示鱼粉样品中原料的成分构成。本研究结果表明,高通量测序技术可应用于鱼粉质量评估,有助于快速了解鱼粉构成,对其质量及用途进行指导,同时,提示该技术可进一步应用于鱼粉掺杂掺假及致病微生物的监测工作中,对保障鱼粉产品质量、维护正常市场秩序具有重要意义。