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1.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.  相似文献   

2.
Summary  A new monotypic bamboo genus Phuphanochloa (Poaceae: Bambusoideae) from north-eastern Thailand is described, together with a new species, P. speciosa.  相似文献   

3.
The tribe Forsythieae comprises 2 genera (Forsythia and Abeliophyllum) and 14 species distributed mostly in the Far East. Although Forsythieae is considered monophyletic, with many symplesiomorphic characters, the phylogenetic status of Abeliophyllum remains controversial. We assessed the phylogenetic relationships of Forsythieae, based on a 3.3-kb plastid fragment (trnL-F region and matK gene) and nuclear internal transcribed spacer (ITS) region DNA sequences. We obtained a highly resolved and strongly supported topology with possible outgroups. The topology of the combined tree was congruent with those of the ITS region and matK gene. Maximum parsimony, maximum likelihood, and Bayesian inference tree analyses for the combined data also yielded identical relationships. Combined sequence data strongly supported the monophyly of Forsythieae and the close relationship between Fontanesia and Jasminum. Oleaceae, not Fontanesia, was found to be a sister group to Forsythieae. Moreover, the genus Abeliophyllum was distinctly independent of Forsythia. Three Forsythia lineages were suggested: (a) ONJ (ovata-nakaii-japonica clade), (b) VGE (viridissima-giraldiana-europaea), and (c) KISS (koreana-intermedia-saxatilis-suspensa). Our results indicated that F. × intermedia is not a hybrid between F. suspensa and F. viridissima, but further studies are needed to determine its taxonomic identity. Furthermore, the diverse fruit shapes in Oleaceae are assumed to be the result of parallelism or convergence.  相似文献   

4.
Sequences of mitochondrial (cytochrome b) and nuclear (recombination activating gene 1–RAG1) DNA markers were obtained for two species of the genus Alburnoides, the Taskent riffle minnow A. oblongus Bulgakov 1923 and the Terek spirlin A. gmelini Bogutskaya and Coad 2009. Phylogenetic analysis revealed that A. oblongus belongs to the genus Alburnus.  相似文献   

5.
New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.  相似文献   

6.
To construct an evolutionary hypothesis for the genus Frankia, gyrB (encoding gyrase B), nifH (encoding nitrogenase reductase) and glnII (encoding glutamine synthetase II) gene sequences were considered for 38 strains. The overall clustering pattern among Frankia strains based on the three analyzed sequences varied among themselves and with the previously established 16S rRNA gene phylogeny and they did not reliably reflect clear evolution of the four discerned Frankia clusters (1, 2, 3 and 4). Based on concatenated gyrB, nifH and glnII, robust phylogenetic trees were observed with the three treeing methods (Maximum Likelihood, Parsimony and Neighbor-Joining) and supported by strong bootstrap and posterior probability values (>75%) for overall branching. Cluster 4 (non-infective and/or non-nitrogen-fixing Frankia) was positioned at a deeper branch followed by cluster 3 (Rhamnaceae and Elaeagnaceae infective Frankia), while cluster 2 represents uncultured Frankia microsymbionts of the Coriariaceae, Datiscaceae, Rosaceae and of Ceanothus sp. (Rhamnaceae); Cluster 1 (Betulaceae, Myricaceae and Casuarinaceae infective Frankia) appears to have diverged more recently. The present study demonstrates the utility of phylogenetic analyses based upon concatenated gyrB, nifH and glnII sequences to help resolve previously unresolved or poorly resolved nodes and will aid in describing species among the genus Frankia.  相似文献   

7.
Summary  A taxonomic revision of the palm genus Podococcus (Arecaceae) is presented. Two species are recognised: P. barteri, a species relatively widespread in a coastal band from Nigeria to the D. R. Congo and P. acaulis, a species previously considered conspecific to P. barteri, almost exclusively confined to Gabon. The taxonomic history, morphology, distribution and conservation status of the genus and each species are discussed  相似文献   

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10.
Taxonomic changes are made to reflect a reassessment of morphology based on the results of molecular phylogenetic studies. A new genus, Davilanthus, is described to include six species that collectively form the sister group to Simsia, and includes the following species transferred from Viguiera: Davilanthus davilae, Davilanthus hidalgoanus, Davilanthus hypargyreus, Davilanthus huajuapanus, Davilanthus purpusii, and Davilanthus sericeus. Three species formerly placed in Viguiera ser. Grammatoglossae are transferred to Simsia: Simsia benziorum, Simsia ovata, and Simsia rhombifolia.  相似文献   

11.
12.
Summary  Eleven species comprising the Madagascan genus Vaughania are subsumed within the large pantropical genus Indigofera. Six new combinations are made; the remaining species were originally described in Indigofera.  相似文献   

13.
The genus Jatropha (Euphorbiaceae) contains species that are of significant economic and ornamental value. However, Jatropha breeding material is rather limited due to incomplete information regarding phylogenetic relationships among germplasm resources. Phylogenetic analyses were performed based on the internal transcribed spacer of nuclear ribosomal DNA (nrDNA ITS), two chloroplast regions (trnL-F and rbcL), and the combined (ITS+trnL-F+rbcL) dataset among twenty-five specimens representing six key Jatropha species. Phylogenetic relationships of Jatropha were well resolved between subgenus Curcas and subgenus Jatropha, and demonstrated the intermediate position of section Polymorphae among sections of both subgenera. Jatropha curcas and J. integerrima demonstrated a close phylogenetic relationship. The molecular data agreed with the morphological classification that recognized J. multifida and J. podagrica in sec. Peltatae. The distinct intraspecific divergence that occurred in J. curcas could be attributed to restricted gene flow caused by geographical isolation and different ecological conditions. Phylograms produced with trnL-F and rbcL sequence data suggested slow rates of sequence divergence among Jatropha spp., while the ITS gene tree had good resolution suggesting high genetic variation of ITS among Jatropha species.  相似文献   

14.
Summary  Three new species are described in Barleria L. sect. Stellatohirta M. Balkwill from tropical Africa: B. aristata from south-central Tanzania, B. aenea from south-western Tanzania and northeast Zambia, and B. purpureotincta from south-western Zambia. Their affinities and conservation status are discussed.  相似文献   

15.
DNA sequences of Capitotricha bicolor from Quercus, Fagus sylvatica, Alnus alnobetula, and Nothofagus, and C. rubi from Rubus idaeus were obtained from apothecia to establish whether specimens from different hosts belong to separate species. The obtained ITS1–5.8S–ITS2 rDNA sequences were examined with Bayesian and parsimony phylogenetic analyses. Intra- and interspecific variation was also investigated based on molecular distances in the ITS region. The phylogenetic analyses supported the specific distinctness of Capitotricha rubi and the Capitotricha from Nothofagus, but also suggest specific distinctness between samples from Quercus, Fagus, and Alnus. The interspecific distances were larger than intraspecific distances for all examined units. The smallest distance was found between the “Alnus alnobetula” and “Fagus sylvatica” units. Two new sequences of Brunnipila are published. Capitotricha, Lachnum, and Erioscyphella are compared to each other based on hair and excipulum characteristics.  相似文献   

16.
The mitochondrial cytochrome c oxidase subunit I gene sequence was recently developed for DNA barcoding of red algal species. We determined the 1245 base pairs of the gene from 27 taxa of an agar-producing species, Gracilaria vermiculophylla, and putative relatives and compared the results with rbcL data from the same species. A total of 392 positions (31.5%) were variable, 282 positions (22.6%) were parsimoniously informative, and average sequence divergence was 13% in an ingroup. Within G. vermiculophylla, pairwise divergence of the gene was variable up to 11 bp (0.9%). Seven recognized haplotypes of cox1 tended to be geographically related. In the aligned 1386 bp of rbcL, three haplotypes were recognized. These results suggest that cox1 is a valuable molecular marker within species and will be very useful in haplotype analyses.  相似文献   

17.
The objective of this study was to construct a molecular phylogeny of the genus Musa using restriction-site polymorphisms of the chloroplast (cpDNA) and mitochondrial DNA (mtDNA). Six cpDNA and two mtDNA sequences were amplified individually in polymerase chain reaction (PCR) experiments in 13 species representing the four sections of Musa. Ensete ventricosum (W.) Ch. was used as the outgroup. The amplified products were digested with ten restriction endonucleases. A total of 79 restriction-site changes were scored in the sample. Wagner parsimony using the branch and bound option defined two lines of evolution in Musa. One lineage comprised species of the sections Australimusa and Callimusa which have a basic number of x = 10 chromosomes, while most species of sections Eumusa and Rhodochlamys (x = 11) formed the other lineage. Musa laterita Cheesman (Rhodochlamys) had identical organellar genome patterns as some subspecies of the Musa acuminata Colla complex. The progenitors of the cultivated bananas, M. acuminata and Musa balbisiana Colla, were evolutionarily distinct from each other. Musa balbisiana occupied a basal position in the cladogram indicating an evolutionarily primitive status. The close phylogenetic relationship between M. laterita and M. acuminata suggests that species of the section Rhodochlamys may constitute a secondary genepool for the improvement of cultivated bananas.Communicated by H.F. Linskens  相似文献   

18.
The genus Leucheria Lag. (Asteraceae Bercht. and J. Presl, tribe Nassauvieae Cass.) comprises 45 species and three infraspecific taxa distributed in the Andean region from southern Chile and Argentina to Peru. Six species are annual herbs. The genus has had a long taxonomic history involving the transference of species described originally under many different genera. The main objectives of this paper were to determine the phylogenetic relationships of species of Leucheria, examine the hypothesis that the ancestor of Leucheria would have originated in a forested habitat and examine the validity of nine morphologically defined evolutionary lines recognized in earlier work on the genus. Additionally we investigated whether the annual species of Leucheria are derived. We extracted DNA from leaf material for 45 taxa (94%) of Leucheria. We used Bayesian inference and plastid and nuclear genes to construct a phylogenetic hypothesis. Results show that Leucheria is monophyletic and is comprised of two main clades. One clade comprises perennial acaulescent/subacaulescent species, all with a solitary capitulum. We recognized three lineages in the second clade comprised of caulescent species that exhibit multiple capitula. Optimization of life-form over the phylogeny showed that five of the six annual species studied are derived in our tree. We conclude that the appearance of the annual habit is associated with the colonization of arid conditions in the winter rainfall coastal desert of northern Chile. Our result shows that species of Leucheria from forested habitats are derived. Discrepancies with previously recognized morphologically defined evolutionary lines were detected.  相似文献   

19.
The phylogeny of the cetrarioid lichens with bifusiform spermatia and dorsiventral thalli which contain usnic acid is reanalysed using three parts of the genome, ITS rDNA, β-tubulin and GAPDH sequences. Molecular data from five cetrarioid species are presented for the first time, and 13 new sequences are combined with sequences from the gene bank to delimit the genus Nephromopsis. A monophyletic clade of Nephromopsis, Tuckneraria, ‘Cetraria’ leucostigma and ‘C.’ melaloma is identified and circumscribed as one genus, Nephromopsis, which now includes 19 species. Four new combinations are presented. A key to the species is provided.  相似文献   

20.
We have developed a protocol for the in vitro propagation of the genus Clivia. Shoots were regenerated when fragments of the peduncle-pedicel junction (PP junction) from young inflorescences were used as explants. The optimal media for PP junction were Murashige and Skoog (MS)-based medium containing 10 M of 6-benzyladenine (BA) and 10 M of 2,4-dichlorophenoxyacetic acid (2,4-D) or MS supplemented with 5 M BA, 10 M -naphthaleneacetic acid (NAA), 250 mg l-1 glutamine and 500 mg l–1 casein hydrolysate and their usage depended on the breeding lines. Multiplication from initiations and in vitro seedlings was the best when the explants were cut longitudinally through the meristem and placed on MS plus 44 M BA. Plantlets were transferred on to hormone -free MS medium with charcoal for rooting.  相似文献   

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