南海赤潮亚历山大藻的分子鉴定及"塔玛复合种"的分子系统发生分析

利用SSu rDNA和ITS分子指标,结合GenBank和其他文献中的基因序列构建了系统树,对一株分离自我国南海的亚历山大藻"塔玛复合种"NH01进行了鉴定,发现SSU rDNA和ITS序列构建的系统树中,不同地理基因型的"塔玛复合种"均构成独立分支.与我国沿海所有的"塔玛复合种"一致,NH01也属于"亚洲温带"型.探...     

广东徐闻地区滨珊瑚遗传多样性和系统发生关系

利用ITS区和12SrRNA基因对广东徐闻地区7种滨珊瑚科珊瑚的遗传多样性和系统发生关系进行了研究。结果表明:(1)基于ITS1检测到在58个样本中有48个单倍型,多样性在0.800—1.000之间,多态位点数在5—62之间,核苷酸多样性指数在0.012—0.094之间;基于ITS2检测到43个单倍型,多样性在0.742—1.000之间,多态位点数在22—75之间,核苷酸多样性指数在0.017—0.175之间。基于ITS区所得遗传分化系数在0.00409—0.12170之间(P<0.001),遗传分化不明显,7种珊瑚中,二异角孔珊瑚的遗传多样性最丰富。(2)以12SrRNA基因建立的系统发育树与传统的形态学分类系统基本吻合,7种珊瑚被分成了3个支系,滨珊瑚属3种为一个支系,二异角孔珊瑚为一个支系,其余3种角孔珊瑚为一个支系。     

On four closely related hypotrichous ciliates (Protozoa, Ciliophora, Spirotrichea): molecular characters, interspecific relationships and phylogeny defined with multigene sequence information

In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates, Holosticha-complex, four closely related holostichids (five populations), Holosticha bradburyae, H. diademata, Anteholosticha sp., and A. manca, were compared and analyzed using ITS2 secondary structures, ITS1-5.8S-ITS2 region and SSrRNA gene sequences. The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced, and they shared sequence identities ranging from 68.0% to 90.1%, while two populations of Anteholosticha sp. differed in three nucleotides (sequence identity 99.8%). There were several minor differences among ITS2 secondary structures of these species, while two populations of Anteholosticha sp. had the identical secondary structure. Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms (Neighbor-Joining, Maximum Parsimony and Bayesian) revealed similar topologies. The results show that:(1) Holosticha bradburyae and H. diademata firmly clustered together with strong bootstrap supports, forming a sister clade with Anteholosticha sp., (2) Anteholosticha appeared to be a paraphyletic assemblage, in which the morphotype A. manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp. Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha, nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.     

ITS sequence analysis of Artemisia halodendron in different habitat gradients

The aim of the present study is to investigate the difference between ITS sequences of Artemisia halodendron Turcz. from different habitat gradients in Horqin Sandy Land, with Artemisia depauperata Krasch. selected as the outgroup. Results indicate that the total length of A. halodendron ITS is 696 bp, the lengths of unaligned ITS-1 and ITS-2 sequences varied from 253 to 256 bp and 264 to 269 bp, respectively, and GC content of ITS-1 and ITS-2 sequences ranged from 54.02% to 54.77% and 56.75% to 58.64%, respectively. This indicates a high difference of length and composition of sequences in ITS-1 than ITS-2. The genetic identity between ITS sequences of A. halodendron from nine populations ranged from 85.7% to 99.7% which indicates some genetic differentiation between sequences. In the maximum parsimony (MP) tree, most ITS sequences from A. halodendron show two major clades: Clade I and Clade II, with Clade II older than Clade I. The order is subp4 → subp1 → subp2 → subp3 → subp8 → subp6 → subp7 → subp9 → subp5, and corresponding habitat order is: inter-dune lowlands → semi-mobile dune → mobile dune → semi-fixed dune → fixed dune. This indicates a close relation between the evolutionary processes of A. halodendron and desertification forming processes and ecological restoration processes of Horqin Sandy Land.     

不同花纹文蛤(Meretrix meretrix)的ITS2分析

采用分子生物学方法,进行了江苏和广西两个地区不同花纹文蛤群体的核糖体DNA转录间隔区(ITS2)的序列分析研究。结果表明,广西的文蛤群体和江苏的群体相比较,仅发现江苏群体在333—336bp处发生了缺失,江苏群体内不同花纹文蛤个体间的ITS2也发生了变化。聚类分析结果证实了序列分析结果,广西文蛤群体和江苏文蛤群体间发生了遗传变异,江苏文蛤群体内部也发生了遗传分化。     

中国球状绿藻新纪录属-索囊藻属(Choricystis)

在西藏那曲的错鄂和湖北武汉的紫阳湖采集到两株淡水绿色海绵。形态观察显示,两株海绵呈现绿色是由于其内共生有球状绿藻。基于形态观察和分子系统发育分析确定为该球状绿藻为索囊藻属的寄生索囊藻(Choricystis parasitica(K.Brandt)Pr?scholdDarienko)。结果表明:(1)两株藻均为纺锤形或倒卵形,长1.2—2.8μm,宽0.8—1.5μm;具一个侧位片状色素体;(2)依据18S r DNA和rbc L cp DNA的进化分析显示这两株藻均位于胶球藻科(Coccomyxaceae),索囊藻属(Choricystis);(3)基于ITS2的二级结构分析显示这两株藻与寄生索囊藻具有相同的二级结构,表明这两株内共生的球状绿藻均为寄生索囊藻。寄生索囊藻为中国新纪录种,所在属索囊藻属为中国新纪录属。本研究以形态性状和分子性状描述了采自中国的寄生索囊藻标本,为今后研究提供依据和参考。     

A pilot study of genetic differentiation between two phenotypes of a Mediterranean population of the bivalve Cerastoderma glaucum and genetic discrimination with other Cerastoderma glaucum and Cerastoderma edule populations outside the Mediterranean

The internal transcribed spacer 1 (ITS1) region of 29 individuals of Cerastoderma glaucum (from the Mediterranean Sea, the Atlantic and the North Sea) and 18 individuals of Cerastoderma edule (from the Atlantic and the North Sea) and the cytochrome c oxidase subunit I (COI) region of 43 individuals of C. glaucum (from the Mediterranean Sea, the Atlantic and the North Sea) and 9 individuals of C. edule (from the Atlantic and the North Sea) were PCR amplified and sequenced. The ITS1 sequences led us to describe 27 genetic haplotypes, while 21 genetic haplotypes were determined via the COI sequences. The ITS1 and the COI sequences revealed an important genetic variability within the Mediterranean population of C. glaucum, which contained two different phenotypes: orange foot and yellow foot. A genetic differentiation between the two phenotypes was revealed by the nucleotide diversity index (π) and is strengthened by the AMOVA analysis. This result leads us to suspect the presence of two different groups in the same population of C. glaucum. Nevertheless to be confirmed this hypothesis requires further studies using more locations and a larger number of sample sizes.     

南海赤潮有毒甲藻链状-塔马亚历山大藻的分子鉴定

以核糖体rDNAITS为分子指标,采用RFLP及序列分析方法对南海海域Alexandriumcatenella和Alexandriumtamarense进行分析和鉴定,并通过与日本海域不同海区A.tenella和A．tamarense的比较,得出A．catenella或A．tamarense的不同地理株的种内个体间ITS区序列非常相似,而种间序列则有显著差异,表明了ITS区用于不同海区A．catenella和A．tamarense种间鉴定是一个较稳定的指标．可看出,ITS区的研究从一个新的角度为海洋微藻种的界定提供了很好的依据．     

中国明对虾核糖体ITS1序列分析及其在对虾科系统分析中的应用

对采自不同群体的5个中国明对虾个体的核糖体RNA转录单元内间隔区1(ITS1)序列特点进行分析,并利用GeneBank数据库中已有的对虾科(Penaeidae)ITS1同源序列对对虾科虾类进行系统分析,探讨ITS1序列在对虾科系统及演化中的应用.结果表明,中国明对虾ITS1序列在个体间和个体内都表现出长度多态性,序列长度范围为637～652 bp,这种长度多态性主要是由于微卫星DNA简单重复序列的重复次数不同所造成.在中国明对虾ITS1序列中发现8个微卫星位点,根据目前已知的12种对虾的ITS1序列,发现某些微卫星位点只存于1种对虾中,如(CAGC)_(2-4)只存在于中国明对虾中,(CGGA)_(4-9)只存在于斑节对虾中,(GCGA)_4只存在于短沟对虾中.利用ITS1序列对12种对虾进行的系统分析表明,12种对虾分为4个类群,同种的不同个体,同属的不同种各自聚支,与形态分类比较吻合.对虾科属间遗传距离范围为0.313～0.977,平均值为0.633,远高于用线粒体基因片段得出的属间的遗传距离,支持将原对虾属的6个亚属提升为属的观点.