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1.
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. In comparison with the results from nuclear and mitochondrial data, we used nuclear gene data as our preferred phylogenetic hypothesis. We proposed two families (Ranidae, Dicroglossidae) for Chinese ranids, with the exception of genus Ingerana. Within Dicroglossidae, four tribes were supported including Dicroglossini, Paini, Limnonectini, and Occidozygini. A broader sampling strategy and evidence from additional molecular markers are required to decisively evaluate the evolutionary history of Chinese ranids.  相似文献   

2.
The patterns and rates of nucleotide substitution in mitochondrial ribosomal RNA genes are described and applied in a phylogenetic analysis of fishes of the subfamily Serrasalminae (Teleostei, Characiformes, Characidae). Fragments of 345 bp of the 12S and 535 bp of the 16S genes were sequenced for 37 taxa representing all but three genera in the subfamily. Secondary-structure models based on comparative sequence analysis were derived to characterize the pattern of change among paired and unpaired nucleotides, forming stem and loop regions, respectively. Base compositional biases were in the direction of A-rich loops and G-rich stems. Ninety-five percent of substitutions in stem regions were compensatory mutations, suggesting that selection for maintenance of base pairing is strong and that independence among characters cannot be assumed in phylogenetic analyses of stem characters. The relative rate of nucleotide substitution was similar in both fragments sequenced but higher in loop than in stem regions. In both genes, C-T transitions were the most common type of change, and overall transitions outnumbered transversions by a factor of two in 16S and four in 12S. Phylogenetic analysis of the mitochondrial DNA sequences suggests that a clade formed by the generaPiaractus, Colossoma, andMylossoma is the sister group to all other serrasalmins and that the generaMyleus, Serrasalmus, andPristobrycon are paraphyletic. A previous hypothesis concerning relationships for the serrasalmins, based on morphological evidence, is not supported by the molecular data. However, phylogenetic analysis of host-specific helminth parasites and cytogenetic data support the phylogeny of the Serrasalminae obtained in this study and provide evidence for coevolution between helminth parasites and their fish hosts.  相似文献   

3.
中国沙塘鳢属鱼类线粒体12S rRNA基因序列分析   总被引:6,自引:0,他引:6  
沙塘鳢属鱼类为东亚特有的小型淡水经济鱼类,中国产沙塘鳢属鱼类分类问题长期存在争议。本文测定了中国产沙塘鳢属鱼类全部种类的线粒体12S rRNA基因部分序列,结合GenBank中下载的2种日本沙塘鳢属鱼类和塘鳢科鱼类同源序列,探讨中国产4种沙塘鳢属鱼类的物种有效性,分析沙塘鳢属鱼类的系统发育关系。作者所使用的同源序列长度为690bp,其中变异位点258个,简约信息位点201个,包括插入/缺失位点34个,转换/颠换平均值为3.0,表明12S rRNA基因是研究沙塘鳢属鱼类系统发育关系的合适分子标记。基于p-distance模型的6种沙塘鳢属鱼类种内遗传距离为0.000—0.024,种间遗传距离为0.058—0.064,支持暗色沙塘鳢和中华沙塘鳢为不同种,中国产沙塘鳢属鱼类包括中华沙塘鳢、河川沙塘鳢、海丰沙塘鳢、鸭绿江沙塘鳢4个种的观点;至于中国还有没有新的沙塘鳢属鱼类,尚有待进一步研究。系统发育分析表明海丰海塘鳢是河川沙塘鳢的姐妹群,暗色沙塘鳢与O.hikimius的亲缘关系最为密切,而同属其余类群之间的系统发育关系则由于自展数据支持率较低而尚不明确。中国产沙塘鳢和日本产沙塘鳢并未单独分群,推测沙塘鳢属鱼类的共同原始祖先可能广泛分布于中国、朝鲜和日本等东亚地区,约在4.9—6.5百万年前的上新世开始分化,系统发育过程比较适合离散假说。  相似文献   

4.
In this study, we investigated molecular phylogenetic status of the marbled polecat (Vormela peregusna) from Bulgaria, using sequences of two Y-chromosomal genes (SRY and ZFY). The phylogenetic tree inferred using combined sequences of both genes indicated that the marbled polecat was split from genera Lutra, Neovison and Mustela after genus Martes was diverged in family Mustelidae. In addition, we analyzed molecular phylogeography of the Bulgarian population of the marbled polecat, using cytochrome b and control region sequences of mitochondrial DNA (mtDNA). The phylogenetic tree of cytochrome b indicated that the haplotypes of the Bulgarian population comprised two haplogroups, which were the most ancestral clades. Additionally, the control region phylogeny showed that the haplotypes of Bulgaria formed two haplogroups: one was the most ancestral clade, and the other was the derivative clade. One individual with the most ancestral cytochrome b clade had a control region haplotype of the derivative clade. Thus, this study revealed that the most ancestral lineages of the marbled polecat are included in the population of Bulgaria. The Bulgarian population could be a remnant lineage from a basal for the species, which in Pleistocene occupied a relatively large area related to the Balkan-Caucasian.  相似文献   

5.
The existing taxonomy of Euryalida, one of the two orders of the Ophiuroidea (Echinodermata), is uncertain and characterized by controversial delimitation of taxonomic ranks from genus to family-level. Their phylogeny was not studied in detail until now. We investigated a dataset of sequence from a mitochondrial gene (16S rRNA) and two nucleic genes (18S rRNA and 28S rRNA) for 49 euryalid ophiuroids and four outgroup species from the order Ophiurida.The monophyly of the order Euryalida was supported as was the monophyly of Asteronychidae, Gorgonocephalidae and an Asteroschematidae + Euryalidae clade. However, the group currently known as the Asteroschematidae was paraphyletic with respect to the Euryalidae. The Asteroschematidae + Euryalidae clade, which we recognise as an enlarged Euryalidae, contains three natural groups: the Asteroschematinae (Asteroschema and Ophiocreas), a new subfamily Astrocharinae (Astrocharis) and the Euryalinae with remaining genera. These subfamilies can be distinguished by internal ossicle morphology.  相似文献   

6.
系统发育关系的构建对被子植物分类及进化研究非常重要。长期以来,被子植物系统发育的研究,大多使用质体基因、线粒体基因或少数保守的单拷贝核基因。该研究从已注释基因组或转录组中搜集88种被子植物(包含58目)的核基因集;通过对其进行同源基因聚类及去旁系同源基因,获得了5 993个一对一的直系同源基因家族(即对于每个基因家族,每种植物最多一条序列,最少包含50个物种);使用截取各种不同数目基因集的DNA或氨基酸序列,采用串联法(concatenation)和溯祖法(coalescence),共构建了20棵进化树。比较这些进化树,虽然大部分结果支持APG IV中描述的被子植物主要支系之间的关系[(真双子叶植物,单子叶植物),木兰类植物],但真双子叶植物内部各目分支的演化关系与APG IV有一个很大的不同,即认为檀香目和石竹目是蔷薇类植物的姊妹群。基于这些进化树,估算了被子植物各目分支的分化时间,结果表明被子植物的起源时间为237.78百万年前(95%置信区间为202.6~278.08),与主流观点认为的225百万年至240百万年前一致。以上结果为构建进化树提供了一种可行性策略,这种方法允许使用基...  相似文献   

7.
An angiosperm phylogeny was reconstructed in a maximum likelihood analysis of sequences of four mitochondrial genes, atpl, matR, had5, and rps3, from 380 species that represent 376 genera and 296 families of seed plants. It is largely congruent with the phylogeny of angiosperms reconstructed from chloroplast genes atpB, matK, and rbcL, and nuclear 18S rDNA. The basalmost lineage consists of Amborella and Nymphaeales (including Hydatellaceae). Austrobaileyales follow this clade and are sister to the mesangiosperms, which include Chloranthaceae, Ceratophyllum, magnoliids, monocots, and eudicots. With the exception of Chloranthaceae being sister to Ceratophyllum, relationships among these five lineages are not well supported. In eudicots, Ranunculales, Sabiales, Proteales, Trochodendrales, Buxales, Gunnerales, Saxifragales, Vitales, Berberidopsidales, and Dilleniales form a basal grade of lines that diverged before the diversification of rosids and asterids. Within rosids, the COM (Celastrales-Oxalidales-Malpighiales) clade is sister to malvids (or rosid Ⅱ), instead of to the nitrogen-fixing clade as found in all previous large-scale molecular analyses of angiosperms. Santalales and Caryophyllales are members of an expanded asterid clade. This study shows that the mitochondrial genes are informative markers for resolving relationships among genera, families, or higher rank taxa across angiosperms. The low substitution rates and low homoplasy levels of the mitochondrial genes relative to the chloroplast genes, as found in this study, make them particularly useful for reconstructing ancient phylogenetic relationships. A mitochondrial gene-based angiosperm phylogeny provides an independent and essential reference for comparison with hypotheses of angiosperm phylogeny based on chloroplast genes, nuclear genes, and non-molecular data to reconstruct the underlying organismal phylogeny.  相似文献   

8.
With about 60,000 described species, Curculionoidea represent the most species-rich superfamily in the animal kingdom. The immense diversity apparently creates difficulties in the reconstruction of the phylogenetic relationships. Independent morphological studies have led to very different classifications. This study is based on molecular data from two independent molecular sources, the 16S and 18S rDNA. Sensitivity analyses were conducted for the sequence alignment (gap costs were varied) as well as the phylogenetic reconstruction algorithms and some of their parameters. The higher-level relationships reconstructed within Curculionoidea are sensitive to alignment and reconstruction method. Nemonychidae or Oxycorynidae+Belidae were found to be sister to all remaining Curculionoidea in many analyses. The 16S rDNA sequence data (obtained from 157 species) corroborate many tribes and genera as monophyletic. It is observed that the phylogenetic reconstruction of genera with specific genetic features such as polyploidy and parthenogenetic reproduction is difficult in weevils. The curculionid subfamily Lixinae appears monophyletic. A new monophylum consisting of Entiminae, Hyperinae, Cyclominae, Myllorhinus plus possibly the Cossoninae is distinguished and we call it Entiminae s.l. For most other subfamilies and families homoplasy concealed the phylogenetic signal (due to saturation of the 16S sequences), or the species sampling was insufficient, although our sampling scheme was rather broad. We observed that although data from one source can easily be misleading (16S) or hardly informative (18S), the combination of the two independent data sets can result in useful information for such a speciose group of organisms. Our study represents the most thorough analysis of molecular sequence data of the Curculionoidea to date and although the phylogenetic results appear less stable than expected, they reflect the information content of these sequence data realistically and thus contribute to the total knowledge about the phylogeny of the Curculionoidea.  相似文献   

9.
The sequence of the mtDNA of the grey seal, Halichoerus grypus, was determined. The length of the molecule was 16,797 base pairs. The organization of the molecule conformed with that of other eutherian mammals but the control region was unusually long due to the presence of two types of repeated motifs. The grey seal and the previously reported harbor seal, Phoca vitulina, belong to different but closely related genera of family Phocidae, true (or earless) seals. In order to determine the degree of differences that may occur between mtDNAs of closely related mammalian genera, the 2 rRNA genes, the 13 peptide coding genes, and the 22 tRNA genes of the 2 species were compared. Total nucleotide difference in the peptide coding genes was 2.0–6.1%. The range of conservative difference was 0.0–1.5%. In the inferred peptide sequences the amino acid difference was 0.0–4.5%, and the difference with respect to chemical properties of amino acids was 0.0–3.0%. A gene that showed a limited degree of difference in one mode of comparison did not necessarily show a corresponding limited difference in another mode. The ratio for differences in codon positions 1, 2, and 3 was 2.7:1:16. The corresponding ratio for conservative differences was 1.8:1. l:1. The evolutionary separation of the two species was calculated to have taken place 2–2.5 million years ago. This dating gives the figure 8 × 10–9 as the mean rate of substitution per site and year in the entire mtDNA molecule. Comparison with the cytochrome b gene of the Hawaiian monk seal and the Weddell seal suggested that the lineage of these two species and that of the grey and harbor seals separated 8 million years ago. Correspondence to: Ú. Árnason  相似文献   

10.
从细胞色素b基因序列探讨笛鲷属的分子系统发生关系   总被引:3,自引:0,他引:3  
测定了9种中国南海的笛鲷属鱼类的细胞色素b基因的部分序列,结合来自GenBank中1种分布于菲律宾和9种分布于美国大西洋的笛鲷属鱼类的相应同源序列,用邻接法和最大简约法构建分子系统树。结果显示:红鳍笛鲷(Lutjanuserythropterus)与红笛鲷(L.sanguineus)之间的同源序列碱基差异百分率只有0.32%,支持二者是同种异名的观点;中国南海的笛鲷属鱼类间的平均碱基差异要高于美国大西洋笛鲷属鱼类。在MP和NJ树中,美国大西洋笛鲷表现为亲缘关系较近,来源于中国南海的笛鲷鱼类相对集中在树的基部,分歧较大。这与所研究的笛鲷地理分布和地理隔离基本相一致,同时也说明中国南海笛鲷分化较早并且分歧较大。  相似文献   

11.
12.
Using nuclear coding and mitochondrial ribosomal genes we try to clarify relationships within Carcharhiniformes with special focus on the two most problematic groups: scyliorhinids and triakids. The mitochondrial aligned sequences are 1542 bp long, and include principally portion of 16S rRNA gene. They are obtained for two outgroup species and 43 Carcharhiniformes species, covering 5 of the 8 families and 15 of the 48 genera of the order. The nuclear RAG1 sequences are 1454 bp long, and are obtained for 17 species representative of the diversity of all species sampled. We used Maximum Parsimony and Maximum Likelihood criteria for tree reconstruction. Paraphylies within the family Scyliorhinidae was proposed for the first time by Maisey [Zool. J. Linn. Soc. 82, 33, 1984] in a morphological cladistic analysis. This result has never been proposed again until recently from molecular phylogenies [Mol. Phylogenet. Evol. 31, 214, 2004]. Here, independent and simultaneous analyses of nuclear and mitochondrial data are congruent in supporting the paraphyly of scyliorhinids. Two groups of scyliorhinids are obtained, thoroughly in line with discrimination proposed by previous authors, based on presence/absence of supraorbital crests on the chondrocranium. The first group (Scyliorhinus+Cephaloscyllium) is basal within carcharhiniforms and the second group (Apristurus+Asymbolus+Cephalurus+Galeus+Parmaturus) is sister group of all the other families investigated (Carcharhinidae, Proscyllidae, Pseudotriakidae, and Triakidae). The paraphyly of triakids appeared probable but more investigations are needed. In conclusion several independent morphological and molecular phylogenetic studies support paraphyly within scyliorhinids. So we propose a new classification for the group, with the redefinition of the family Scyliorhinidae sensu stricto and the resurrection of the family Pentanchidae with a new definition.  相似文献   

13.
The complete nucleotide sequence of the mitochondrial DNA of the rainbow trout, Onchorynchus mykiss, has been determined. The total length of the molecule is 16,660 bp. The rainbow trout mitochondrial DNA has the same organization described in eutherian mammals, the clawed frog (Xenopus laevis), and the two fish species, Oriental stream loach (Crossotoma lacustre) and carp (Cyprinus carpio). Alignment and comparison of the deduced amino acid sequences of the 13 proteins encoded by rainbow trout and other vertebrate mitochondrial genomes allowed us to estimate that COI is the most conserved mitochondrial subunit (amino acid identity ranging from 85.6% to 94.8%) whereas ATPase 8 is the most variable one (amino acid identity ranging from 30.8% to 70.4%). Putative secondary structures for the 22 tRNAs found in the molecule are given along with an extensive comparison of tRNA sequences among representative species of each major group of vertebrates. In this sense, an unusual cloverleaf structure for the tRNASer(AGY) is proposed. A stem-loop structure inferred for the origin of the L-strand replication (OL) and the presence of a large polycytidine tract in the OL loop is described. The existence of this stretch instead of the usual T-rich sequence reported so far in mammal mtDNAs is explained in terms of a less-strict template dependence of the RNA primase involved in the initiation of L-strand replication. Correspondence to: J.M. Bautista  相似文献   

14.
The taxonomy of the Helice s. l. crabs has been recently revised, subdividing the Asian species in three genera, Helice , Helicana and Pseudohelice . The last one is widespread throughout the Indo-West Pacific Ocean and a single species, Pseudohelice subquadrata , is found in Asia. The other two genera appear to be endemic to Asia. However, phylogenetic affinities among the Asian representatives of Helice s. l. are poorly understood, and different morphology-based hypotheses of relationships remain untested. In this study, we used sequence data from a mitochondrial gene-block spanning three different genes [16S rDNA- trnL 1 - IGS -nad1 ] to perform phylogenetic analyses. The results provide independent molecular evidence supporting the splitting of the Asian species into Helice and Helicana . Helice is suggested to be paraphyletic with respect to P. subquadrata . In addition, the heterogeneity of the genus Pseudohelice is shown when including the East Asian and East African counterparts. We propose that the two genera, Helice and Pseudohelice , are not monophyletic in their current composition.  相似文献   

15.
Based on previous molecular and morphological analyses, Eurasian badgers are currently classified into Meles meles distributed in Europe, M. canescens in the Caucasus and Middle East, M. leucurus in continental Asia and M. anakuma in Japan. The precise locations of their distribution boundaries are still unclear. Therefore, in the present study, we clarified the phylogenetic relationships in the genus Meles around its distribution boundaries, based on mitochondrial DNA (mtDNA) and Y-chromosomal genes. From 71 badgers examined, 29 mtDNA haplotypes were identified, including new 26 types. Multiple haplotypes of SRY and CAN-SINEs were identified from 23 males, including two new haplotypes of SRY. The mtDNA phylogeny showed that the Ural Mountains were not a current distribution boundary between M. meles and M. leucurus. In addition, our results supported the hypothesis that the Bosphorus Strait is a geographical barrier between M. meles and M. canescens. The badgers from Bulgaria north of the Bosphorus Strait shared haplotypes with M. meles. On the other hand, badgers from Far Eastern Russia distributed in the eastern peripheral region of the Asian Continent had haplotypes of M. leucurus. The badgers from Norway and Finland shared haplotypes with M. meles.  相似文献   

16.
As a first step towards using cross-species comparison to complete the inventory of the nuclear genes that encode mitochondrial polypeptides, and ultimately to understand their function through systematic molecular and genetic analysis in a model organism of choice, we report here the characterization of 41 Drosophila melanogaster cDNAs. These cDNAs were isolated by screening an ovarian expression library with antibodies against mitochondrial proteins and identify 17 novel Drosophila genes. The deduced amino acid sequences encoded by the majority of these cDNAs turned out to show significant homology to mitochondrial proteins previously identified in other species. Among others, ORFs putatively encoding six different subunits of ATP synthase and three NADH:ubiquinone reductase subunits were detected. By in situ hybridization, all cDNAs were mapped to single bands on polytene chromosomes, thus identifying candidate Drosophila genes required for mitochondrial biogenesis and maintenance. A search of the Human Gene Index database made it possible in most cases to align the entire Drosophila coding sequence with a human consensus sequence, suggesting that the cDNAs originate from insect counterparts of expressed mammalian genes. Our experimental strategy represents an efficient approach to the identification and interspecies comparison of genes encoding products targeted to the mitochondrion. Received: 13 July 1998 / Accepted: 12 October 1998  相似文献   

17.
The first comprehensive cladistic analysis of Reduviidae, the assassin bugs, based on molecular data is presented and discussed in the context of a recently-published morphological analysis. Assassin bugs are essential components of ecosystems, but also important in agriculture and medicine. Sampling included 94 taxa (89 Reduviidae, 5 outgroups) in 15 subfamilies and 24 tribes of Reduviidae and is based on 3300 base pairs of mitochondrial (16S) and nuclear (18S, 28SD2, 28SD3-5) ribosomal DNA. Partitions of the dataset were aligned using different algorithms implemented in MAFFT and the combined dataset was analyzed using parsimony, partitioned maximum likelihood and partitioned Bayesian criteria. Clades recovered in all analyses, independent of alignment and analytical method, comprise: Cimicomorpha and Reduviidae; Hammacerinae; Harpactorinae; Apiomerini; Peiratinae; Phymatinae; Salyavatinae; Triatominae; Phymatinae + Holoptilinae; the higher Reduviidae (Reduviidae excluding Hammacerinae and the Phymatine Complex); Ectrichodiinae + Tribelocephalinae; (Triatominae + Zelurus) + Stenopodainae. Hammacerinae are rejected as sister group to all remaining Reduviidae in all analyses, as is the monophyly of Reduviinae, Emesinae and Harpactorini. High support values for Triatominae imply that blood-feeding has evolved only once within Reduviidae. Stenopodainae and part of Reduviinae are discussed as close relatives to Triatominae.  相似文献   

18.
It has been shown that increased character sampling betters the accuracy of phylogenetic reconstructions in the case of molecular data. A recently published analysis of avian higher-level phylogenetics based on 2954 morphological characters now provides an empirical example to test whether this is also true in the case of morphological characters. Several clades are discussed which are supported by multiple analyses of mutually independent molecular data (sequences of nuclear genes on different chromosomes and mitochondrial genes) as well as morphological apomorphies, but did not result from parsimony analysis of the large morphological data set. Incorrect character scorings in that analysis notwithstanding, it is concluded that in the case of morphological data, increased character sampling does not necessarily better the accuracy of a phylogenetic reconstruction. Because morphological characters usually have a strongly varying complexity, many simple and homoplastic characters may overrule fewer ones of greater phylogenetic significance in large data sets, thus producing a low ratio of phylogenetic signal to 'noise' in the data.  相似文献   

19.
The mitochondrial alternative oxidase is a diiron carboxylate quinol oxidase (Dox) found in plants and some fungi and protists, but not animals. The plastid terminal oxidase is distantly related to alternative oxidase and is most likely also a Dox protein. Database searches revealed that the alpha-proteobacterium Novosphingobium aromaticivorans and the cyanobacteria Nostoc sp. PCC7120, Synechococcus sp. WH8102 and Prochlorococcus marinus subsp. pastoris CCMP1378 each possess a Dox homolog. Each prokaryotic protein conforms to the current structural models of the Dox active site and phylogenetic analyses suggest that the eukaryotic Dox genes arose from an ancestral prokaryotic gene.  相似文献   

20.
Eremiadinae, one of three subfamilies of Lacertidae, are distributed throughout Asia and Africa. Previous phylogenetic studies suggested that one of the main groups of Eremiadinae (the Ethiopian clade) consist of two clades with predominately East‐African and South‐African distribution. Yet, especially the latter one, which includes the genera Pedioplanis, Meroles, Ichnotropis, Tropidosaura and Australolacerta, was not well supported in the molecular phylogenetic analysis. In this study, we analysed the phylogenetic relationships among the genera of the ‘South African clade’ to assess whether this group actually forms a highly supported clade and to address questions concerning the monophyly of the genera. We sequenced sections of the widely used mitochondrial genes coding for 16S rRNA, 12S rRNA and cytochrome b (altogether 2045 bp) as well as the nuclear genes c‐mos, RAG‐1, PRLR, KIF24, EXPH5 and RAG‐2 (altogether 4473 bp). The combined data set increased the support values for several nodes considerably. Yet, the relationships among five major lineages within the ‘South African clade’ are not clearly resolved even with this large data set. We interpret this as a ‘hard polytomy’ due to fast radiation within the South African lacertids. The combined tree based on nine marker genes provides strong support for the ‘South African Clade’ and its sister group relationship with the ‘East African Clade’. Our results confirm the genus Tropidosaura as a monophylum, while Ichnotropis is paraphyletic in our trees: Ichnotropis squamulosa appears more closely related to Meroles than to Ichnotropis capensis. Furthermore, the monophyly of Meroles is questionable as well. Based on our results, I. squamulosa should be transferred from Ichnotropis into the genus Meroles. Also, the two species of Australolacerta (A. australis and A. rupicola) are very distantly related and the genus is perhaps paraphyletic, too. Finally we propose a phylogeographical scenario in the context of palaeoclimatic data and compare it with a previously postulated hypothesis.  相似文献   

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