Significant population genetic structuring of the holoplanktic scyphozoan Pelagia noctiluca in the Atlantic Ocean     

《African Journal of Marine Science》2013,35(3):425-430

Pelagia noctiluca is thought to have a global distribution, yet our understanding of genetic connectivity across the range of this problem animal is poor. Here, we investigate the genetic structure of populations off southern Africa using mitochondrial COI and nuclear ITS1 and ITS2 genes, and compare the results to recent work conducted in the North-East Atlantic. Analyses showed significant differentiation between the southern and northern Atlantic population groups (COI Φ _st = 0.72, ITS2 Φ _st = 0.23, p < 0.001), which suggests historical rather than contemporary gene flow. Southern African samples showed high haplotypic (h = 1) and low nucleotide (π = 0.008) diversity, similar to those from Europe. Phylogenetic analyses suggest South African samples to have diverged earlier than those from the northern Atlantic.  相似文献   

Preliminary study on mitochondrial 16S rRNA gene sequences and phylogeny of flatfishes （Pleuronectiformes）     

尤锋 刘静张培军  相建海 《中国海洋湖沼学报》2005,23(3):335-339

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   

Partial Sequence Analysis of Mitochondrial COI Gene of the Chinese Shrimp, Fenneropenaeus Chinensis   总被引：1，自引：0，他引：1  

GAO Tianxiang  LI Jian  WANG Qingyin  LIU JinxianThe Key Laboratory of Mariculture  Ministry of Education  Ocean University of China  Qingdao  P.R.ChinaYellow Sea Fisheries Research Institute  Chinese Academy of Fishery Sciences  Qingdao  P.R.China 《中国海洋大学学报(英文版)》2003,2(2)

Eight hundred and thirty eight base pair fragment of mitochondrial COI gene of wild and cultured populations (CP1, CP4, CP5 and CP6) of Fenneropenaeus chinensis was amplified and sequenced. The A, T, G and C contents of the sequence were 235bp (28.0% ),.307bp (36.6%), 138bp (16.5%) and 158bp (18.9%), respectively. Furthermore, 556bp fragment of the sequence was used to discuss the phylogenetic relationship among 14 Penaeidae species using Alpheus armillatus as the outgroup. From the molecular phylogenetic tree constructed by neighbor-joining method, we obtained three large shrimp groups: Farfantepenaeus, Litopenaeus and Fenneropenaeus group. The results also indicated that there were a closer genetic relationships between F. aztecus and F. paulensis, L. schmitti and L. setiferus, F. indicus and F. merguiensis, and the genus Farfantepenaeus was closer to Litopenaeus.  相似文献   

Allometry in the pliocene bivalveAstarte omalii: A new look at an old data set     

James C. Brower 《Mathematical Geology》1995,27(3):399-420

The relationships between ontogeny and phylogeny have been studied for the bivalve Astarte omaliifrom the Lower, Middle, and Upper Pliocene of Belgium using canonical variates analysis, principal components in the form of multivariate allometry, and bivariate power functions or allometric equations. The results indicate that the three samples represent segments of a single evolutionary lineage which is characterized mainly by paedomorphosis where adult descendants are similar to juvenile ancestors. Recapitulation or peramorphosis is only observed for a single parameter. The Lower and Middle Pliocene samples are considered as Astarte omalii omalii,whereas the Upper Pliocene specimens are placed in A. omalii basteroti.The evolutionary trends most likely reflect changes in the living positions of the bivalves.  相似文献   

A new species of the genus Besania Brough 1939 from the Middle Triassic of Canton Grisons (Switzerland) with a discussion of the phylogenetic status of the taxon     

Annette Herzog  Toni Bürgin 《Eclogae Geologicae Helvetiae》2005,98(1):113-122

Recent excavations in the Middle Triassic Prosanto Formation (Ladinian, Ct. Grisons, Switzerland) have produced new material of the genus Besania Brough 1939. These specimens show many previously unrecorded details. Some features differ from those of the type species Besania micrognathus, and we therefore erect a new species, Besania schaufelbergeri sp. nov. This new material has prompted a re-evaluation of the phylogenetic interrelationships of the genus. The taxon seems to be closely related to basal Halecostomi. An erratum to this article is available at .  相似文献   

Evolution: disjunct degeneration of immunological determinants     

Marin  F.  Gillibert  M.  Westbroek  P.  Muyzer  G.  Dauphin  Y. 《Geologie en Mijnbouw》1999,78(2):135-139

The dissolution of calcified invertebrate skeletons releases an elaborate mixture of proteins, glycoproteins and polysaccharides. These skeletal matrix macromolecules are thought to play a major role in calcification and were widely used for phylogenetical studies. We tested the reactivity of water-soluble macromolecules from a wide range of invertebrate skeletons with two antisera raised against the shell matrix of the bivalve, Pinna nobilis. Projections of our results on the phylogenetical tree of Starobogatov (1992) show for the first time that, during evolution, antigenic determinants may degenerate in some stocks while they remain intact in others. The phylogenetic implications of these patterns of disjunct degeneration are discussed.  相似文献   

Phylogeny of the cuttlefishes (Mollusca: Cephalopoda) based on mitochondrial COI and 16S rRNA gene sequence data   总被引：5，自引：0，他引：5  

LIN Xiangzhi  ZHENG Xiaodong  XIAO Shu  WANG Rucai 《海洋学报(英文版)》2004,23(4):699-707

To clarify cuttlefish phylogeny, mitochondrial cytochrome c oxidase subunit I (COI) gene and partial 16S rRNA gene are sequenced for 13 cephalopod species. Phylogenetic trees are constructed, with the neighbor-joining method. Coleoids are divided into two main lineages, Decabrachia and Octobrachia. The monophyly of the order Sepioidea, which includes the families Sepiidae, Sepiolidae and Idiosepiidae, is not supported. From the two families of Sepioidea examined, the Sepiolidae are polyphyletic and are excluded from the order. On the basis of 16S rRNA and amino acid of COI gene sequences data, the two genera (Sepiella and Sepia) from the Sepiidae can be distinguished, but do not have a visible boundary using COI gene sequences. The reason is explained. This suggests that the 16S rDNA of cephalopods is a precious tool to analyze taxonomic relationships at the genus level, and COI gene is fitter at a higher taxonomic level (i.e., family).  相似文献   

Phylogenetic relationship of Podocopida (Ostracoda:Podocopa) based on 18S ribosomal DNA sequences   总被引：1，自引：0，他引：1  

YU N  ZHAO Meiying  CHEN Liqiao  YANG Pin 《海洋学报(英文版)》2006,25(2):99-108

1 IntroductionOstracodaisoneofthelargestgroupsoftheCrus-tacea (M artin and Davis, 2001), and the num bersofliving speciesofostracodesconsistof7 500. OneofthefrustratingaspectsforOstracodastudyisunstabili-tyofthehigherclassification status (Schram, 1986),w…  相似文献   

mtDNA COI基因在轮虫分子系统重建中的意义   总被引：5，自引：0，他引：5  

董云伟  牛翠娟 《海洋湖沼通报》2004,(3):35-41

为分析mtDNA COI基因在轮虫分子系统重建中的作用．扩增并测定了B．calyciflorus和B．quadridentatus mtDNA COI基因部分序列。通过对扩增序列和Genbank中其它轮虫序列进行比较分析．发现COI序列包含丰富的遗传信息。利用Kimura双参数法计算遗传距离，在属和物种水平上间存在不同程度的遗传分化。利用NJ和MP法构建基因树。各物种形成独立进化枝．在属、科水平上与传统分类结果基本一致．这说明COI在轮虫系统重建中具有重要意义。在种内不同的单元型之间存在着遗传差异，部分种类不同地理种群之间存在较大的遗传变异．因此在系统重建过程中要注意种内多态的影响。  相似文献   

Phylogenetic analyses of four species of Ulva and Monostroma grevillei using ITS, rbc L and 18S rDNA sequence data     

林中姮  沈颂东  陈伟洲  李慧慧 《中国海洋湖沼学报》2013,31(1):97-105

Chlorophyta species are common in the southern and northern coastal areas of China. In recent years, frequent green tide incidents in Chinese coastal waters have raised concerns and attracted the attention of scientists. In this paper, we sequenced the 18S rDNA genes, the internal transcribed spacer (ITS) regions and the rbcL genes in seven organisms and obtained 536-566 bp long ITS sequences, 1 377-1 407 bp long rbcL sequences and 1 718-1 761 bp long partial 18S rDNA sequences. The GC base pair content was highest in the ITS regions and lowest in the rbcL genes. The sequencing results showed that the three Ulva prolifera (or U. pertusa) gene sequences from Qingdao and Nan’ao Island were identical. The ITS, 18S rDNA and rbcL genes in U. prolifera and U. pertusa from different sea areas in China were unchanged by geographic distance. U. flexuosa had the least evolutionary distance from U. californica in both the ITS regions (0.009) and the 18S rDNA (0.002). These data verified that Ulva and Enteromorpha are not separate genera.  相似文献