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1.
The most economically important group of species in the genus Amaranthus is the A. hybridus species complex, including three cultivated grain amaranths, A. cruentus, A. caudatus, and A. hypochondriacus, and their putative wild progenitors, A. hybridus, A. quitensis, and A. powellii. Taxonomic confusion exists among these closely related taxa. Internal transcribed spacer (ITS) of nuclear ribosomal DNA, amplified fragment length polymorphism (AFLP), and double-primer fluorescent intersimple sequence repeat (ISSR) were employed to reexamine the taxonomic status and phylogenetic relationships of grain amaranths and their wild relatives. Low ITS divergence in these taxa resulted in poorly resolved phylogeny. However, extensive polymorphisms exist at AFLP and ISSR loci both within and among species. In phylogenetic trees based on either AFLP or ISSR or the combined data sets, nearly all intraspecific accessions can be placed in their corresponding species clades, indicating that these taxa are well-separated species. The AFLP trees share many features in common with the ISSR trees, both showing a close relationship between A. caudatus and A. quitensis, placing A. hybridus in the same clade as all grain amaranths, and indicating that A. powellii is the most divergent taxon in the A. hybridus species complex. This study has demonstrated that both AFLP and double-primer fluorescent ISSR have a great potential for generating a large number of informative characters for phylogenetic analysis of closely related species, especially when ITS diversity is insufficient.  相似文献   

2.
中国苋属nrDNA的ITS序列分析及其系统学意义   总被引:11,自引:0,他引:11  
运用PCR直接测序法,对苋属(Amaranrhus L.)15个种及外类群鸡冠花(Celosia cristata L.)nrDNA的ITS区(包括ITS-1,5.85rDNA和ITS-2)进行序列测定。结果表明苋属植物的ITS序列总长度为629-632bp,长度变异仅发生在ITS-1区(250-253bp)。采用PAUP软件进行系统发育分析表明:分布于中国的苋属植物可分为3组,即刺苋组(secg  相似文献   

3.
The sequences of the ITS region (including ITS-1, 5.8S rDNA and ITS-2) of nuclear ribosomal DNA from 15 species of the genus Amaranthus L. and outgroup Celosia cristata L. were determined. The result shows that the size of the ITS region of Amaranthus is from 629 to 632 bp, and the length variation is only found in ITS-1 (250-253 bp). On the basis of phylogenetic analysis of nucleotide sequences, the Amaranthus species in China may be devided into three sections, viz., sect. Spinosus, sect. Amaranthus and sect. Paucestamen; the cultivated species, viz., Amaranthus paniculatus L., A. cruentus L., A. caudatus L. and A. hypochondriacus L. can be treated as the subsp. of A. hybridus L.; A. taishanensis F.Z.Li and A. tenuifolius Willd are both closely related to species in the sect. Paucestamen. The study also indicated that the number of stamens has more phylogenetic information than other characters, such as the number of sepals and dehiscence/indehiscence of fruits in Amaranthus.  相似文献   

4.
he first internal transcribed spacer (ITS1) of nuclear ribosomal DNA of three wild rice species and two subspecies of cultivated rice, which are distributed in China, was amplified using PCR technique and sequenced with automated fluorescent sequencing. The sequences of ITS1 ranged from 193 bp to 218 bp in size and G/C content varied from 69.3%to 72.7%. In pairwise comparison among the five taxa, sequence site divergence ranged from 1.5 % to 10.6%. Phylogenetic analysis of ITS1 sequences using Wagner parsimony generated a single well-resolved tree, which revealed that Oryza rufipogon was much more closely related to cultivated rice species than to the other two wild species. Oryza granulata was less closely related to either cultivated rice species or the other two wild species, and might be a unique and isolated taxon in the genus Oryza. The phylogenetic relationships of the three wild rice species and two cultivated rice subspecies inferred from ITS1 sequences is highly concordant with those based on the molecular evidence from isozyme, chloroplast DNA (cpDNA), mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) of the genus Oryza.  相似文献   

5.
用 PCR技术从产于我国的 3种野生稻和亚洲栽培稻的 2个亚种中特异地扩增和测序了 r DNA的第一转录间隔区。普通野生稻 (Oryza rufipogon)、药用野生稻 (O.officinalis)、疣粒野生稻 (O.granu-lata)和栽培稻的两个亚种 (O.sativa ssp.indica,O.sativa ssp.japonica)的 ITS1序列为 1 93bp、1 94bp、2 1 8bp、1 94bp和 1 94bp,它们的 G/ C含量为 69.3%~ 72 .7% ,序列中位点趋异率为 1 .5%~ 1 0 .6%。序列的相似性比较和简约性分支分析的结果表明 ,普通野生稻与栽培稻的两个亚种之间的亲缘关系最为密切 ;药用野生稻与普通野生稻和与栽培稻的两个亚种的相似性都为 82 % ,说明它与 AA基因组有一定的亲缘关系 ;疣粒野生稻与普通野生稻、药用野生稻和栽培稻两个亚种的亲缘关系相对较远 ,它在稻属中可能是一个系统地位较独特的类群。以 ITS1序列构建的 3种野生稻和 2个栽培稻亚种的系统发育关系与前人用同工酶、叶绿体 DNA、线粒体 DNA和核 DNA资料重建的稻属的系统发育关系基本一致  相似文献   

6.
Summary Three weedy amaranths (Amarantkus hybridus, A. retroflexus and A. powellii) from nine California sites, three domesticated species (A. caudatus, A. hypochondriacus and A. cruentus) from the USDA plant inventory as well as other sources and a naturally-occurring crop-weed hybrid were studied for numerical taxonomy using morphological and allozyme variation data. The crop and weedy species groups were easily separated and the hybrid populations were found to be intermediate. Surprisingly, very little intraspecific variation was present. Crop, weed and hybrid amaranths were also compared for their yielding ability, harvest index, seed efficiency of grain production and protein, popping quality and other agronomic traits. Although field plot yields were similar among the three groups of species (700 Kg/ha seed without fertilizer treatment and water, ranging to 3000 Kg/ha with fertilizer applications of 170 Kg N/ha, and abundant water), the harvest index of the weedy group was much higher (25–40%) than the domesticated species (10–15%). The allocation of biomass to seed production is positively correlated with seed yield in the domesticated but not in the weedy types, whereas the percentages of biomass as stem material and as seeds are negatively correlated. Several weedy and crop characteristics together should provide the basis of new improved cultivars through genetic recombination and selection.  相似文献   

7.
We examined genetic diversity and relationships among 24 cultivated and wild Amaranthus accessions using the total low-Cot DNA and five individual repetitive sequences as probes. These low-Cot DNA probes were obtained by the isolation of various classes of repetitive-DNA sequences, including satellites, minisatellites, microsatellites, rDNA, retrotransposon-like sequences, and other unidentified novel repetitive sequences. DNA fingerprints generated by different types of repetitive-DNA probes revealed different levels of polymorphism in the Amaranthus genomes. A repetitive sequence containing microsatellites was found to be a suitable probe for characterizing intraspecific accessions, whereas more conservative sequences (e.g. rDNA) were informative for resolving phylogenetic relationships among distantly related species.Genetic diversity, measured as restriction fragment length polymorphism (RFLP) and the similarity index at the low-Cot DNA level, was equally high among intraspecific accessions between the two species groups: grain amaranths (A. caudatus, A. cruentus, and A. hypochondriacus) and their putative wild progenitors (A. hybridus, A. powellii, and A. quitensis). At the interspecific level, however, the grain amaranth species are less divergent from each other than their wild progenitors. With the rare exceptions of certain A. caudatus accessions, grain amaranths were found to be closely related to A. hybridus. The results based on low-Cot DNA were comparable with previous RAPD and isozyme studies of the same set of species/accessions of Amaranthus, indicating that low-Cot DNA sequences are suitable probes for a fingerprinting analysis of plant germplasm diversity and for determining phylogenetic relationships. Received: 19 October 1998 / Accepted: 8 January 1999  相似文献   

8.
This study reports maximum parsimony and Bayesian phylogenetic analyses of selected Old World Astragalus using two chloroplast fragments including trnL-F and ndhF and the nuclear ribosomal internal transcribed spacer (nrDNA ITS). A total of 52 taxa including 34 euploid Old World and New World Astragalus , one aneuploid species from the Neo-Astragalus clade as a representative and 14 other Astragalean taxa, plus Cheseneya astragalina and two species of Caragana as outgroups were analyzed for both trnL-F and nrDNA ITS regions. ndhF was analyzed in 30 taxa and the same number for the combination of these three datasets were examined. In general, the trnL-F dataset and the ndhF and nrDNA ITS datasets generated more or less the same clades within Astragalus . However, in the trnL-F and ndhF phylogenies, Astragalus species are not gathered in a single clade, the so-called Astragalus s.s., as indicated by the nrDNA ITS tree. Visual inspection of these three phylogenies revealed that they were inconsistent regarding the position and relationships of Astragalus hemsleyi , A. ophiocarpus , A. annularis–A. epiglottis / Astragalus pelecinus, A. echinatus and A. arizonicus . Incongruence length difference test suggested that the trnL-F , ndhF and nrDNA ITS datasets were incongruent. In spite of this, phylogenetic analyses of the combined datasets as one unit or as three partitions generated trees that were topologically similar as a mix of the cpDNA and the nrDNA ITS trees. However, the combined dataset provided more resolved and statistically supported clades. The recently described A. memoriosus appeared closely related to A. stocksii (both from sect. Caraganella ) based on both trnL-F and nrDNA ITS sequences.  相似文献   

9.
Abstract: Four molecular markers have been studied to examine the phylogenetic position of the South African plant genus Haworthia Duval within the succulent Asphodelaceae. Sequence data of the chloroplast genes mat K and rbc L were compared to the nuclear markers ITS1 and ISSR (Inter Simple Sequence Repeat) analysis. Both lines of molecular data, chloroplast and nuclear DNA, indicate that Haworthia is polyphyletic, forming two distinct clades. Most taxa previously combined as Haworthia subgenus Haworthia branch off early in the alooid chloroplast trees forming a strongly monophyletic group, whereas subgenus Hexangulares forms a polyphyletic assemblage comprising other alooid genera. The nuclear markers ITS1 and ISSR fingerprinting support the two groups as distinctly different, therefore confirming the division seen in chloroplast DNA. The practical implication is that the generic concept of Haworthia may have to be restricted to H. subgenus Haworthia or alternatively, that the groups of Haworthia be treated as infrageneric taxa within a broadened (Linnaean) concept of Aloe.  相似文献   

10.
Individual specimens of Anisakis, Pseudoterranova, and Contracaecum collected from marine mammals inhabiting northern Pacific waters were used for comparative diagnostic and molecular phylogenetic analyses. Forty-eight new sequences were obtained for this study of 14 Anisakis taxa, 8 Pseudoterranova taxa, 4 Contracaecum taxa, and 4 outgroup species. Partial 28S (LSU) and complete internal transcribed spacer (ITS-1, 5.8S, ITS-2) ribosomal DNA was amplified by the polymerase chain reaction and sequenced. Sequences of ITS indicated that Pseudoterranova specimens from Zalophus californianus (California sea lion), Mirounga angustirostris (northern elephant seal), Phoca vitulina (harbor seal), Enhydra lutris (sea otter), and Eumetopias jubatus (Steller's sea lion) exactly matched P. decipiens s. str., extending the host and geographic range of this species. Anisakis from northern Pacific marine mammals were most closely related to members of the A. simplex species complex. Comparison of Anisakis ITS sequences diagnosed the presence of A. simplex C in 2 M. angustirostris hosts, which is a new host record. Anisakis specimens from Phocoena phocoena (harbor porpoise), Lissodelphis borealis (Pacific rightwhale porpoise), and E. jubatus included 3 ITS sequences that did not match any known species. Contracaecum adults obtained from Z. californianus were most closely related to C. ogmorhini s.l. and C. rudolphii, but ITS sequences of these Contracaecum specimens did not match C. ogmorhini s. str. or C. margolisi. These novel Anisakis and Contracaecum ITS sequences may represent previously uncharacterized species. Phylogenetic analysis of LSU sequences revealed strong support for the monophyly of Anisakinae, Contracaecum plus Phocascaris, Pseudoterranova, and Anisakis. Phylogenetic trees inferred from ITS sequences yielded robustly supported relationships for Pseudoterranova and Anisakis species that are primarily consistent with previously published phenograms based on multilocus electrophoretic data.  相似文献   

11.
The phylogenetic relationships of 60 accessions representing ten species of the genus Hordeum were investigated based on AFLP markers and seed storage protein SDS-PAGE electrophoresis. A total of 339 AFLP polymorphic markers were scored as a result of fingerprinting the studied taxa using seven AFLP primer combinations, whereas 46 polymorphic protein bands resulted from the water soluble and water non-soluble seed storage protein electrophoresis. The phylogenetic tree deduced from AFLP analysis is concordant in a large extent with that deduced from seed storage protein electrophoresis. The studied taxa were clustered according to their genome type into two main groups representing the Old and New World’s species. Inside each group the species were clustered according to their genome type. Highly significant cophenetic correlation coefficient was obtained between both AFLP (0.96) and seed storage protein (0.89) indicating the reliability of the results.  相似文献   

12.
Inferring phylogenetic relationships among closely related plant species is often difficult due to the lack of molecular markers exhibiting enough nucleotide variability at this taxonomic level. Moreover, gene tree does not necessary represent the true species tree because of random sorting of polymorphic alleles in different lineages. A solution to these problems is to use many amplified fragment length polymorphisms (AFLP) distributed throughout the whole genome, to infer cladistic and phenetic among-species relationships. Phylogenetic relationships among interfertile species of Trollius L. (Ranunculaceae) were investigated using nuclear DNA (ITS1+5.8S rRNA+ITS2) and chloroplast DNA (trnL intron and trnL-trnF intergene spacer) sequences, and AFLP markers. ITS sequences were not informative at the intrageneric level, but confirmed the sister relationship between Trollius and Adonis genera, and provided new information on the phylogenetic relationships among five Ranunculaceae genera. Chloroplast DNA was more informative among Trollius species, but not consistent with the sections previously described. AFLP proved to be a powerful tool to resolve the complex genetic relationships between the morphological entities constituting the genus Trollius. Although as much as 76.1% of the total AFLP variability was found within a priori defined morphological groups, the remaining 23.9% variability differentiating groups was sufficient to generate congruent and robust cladistic and phenetic trees. Several morphological traits, independent from those used to define groups, were mapped onto the molecular phylogeny, and their evolution discussed in relation to the absence/presence of pollinator-seed parasite Chiastocheta flies.  相似文献   

13.
 Genetic diversity and relationships of 23 cultivated and wild Amaranthus species were examined using both isozyme and RAPD markers. A total of 30 loci encoding 15 enzymes were resolved, and all were polymorphic at the interspecific level. High levels of inter-accessional genetic diversity were found within species, but genetic uniformity was observed within most accessions. In the cultivated grain amaranths (A. caudatus, A. cruentus, and A. hypochondriacus), the mean value of HT was 0.094, HS was 0.003, and GST was 0.977 at the species level. The corresponding values in their putative wild progenitors (A. hybridus, A. powellii, and A. quitensis) were 0.135, 0.004, and 0.963, respectively. More than 600 RAPD fragments were generated with 27 arbitrary 10-base primers. On average, 39.9% of the RAPD fragments were polymorphic among accessions within each crop species; a similar level of polymorphism (42.8%) was present in the putative progenitors, but much higher levels of polymorphism were found in vegetable (51%) and other wild species (69.5%). The evolutionary relationships between grain amaranths and their putative ancestors were investigated, and both the RAPD and isozyme data sets supported a monophyletic origin of grain amaranths, with A. hybridus as the common ancestor. A complementary approach using information from both isozymes and RAPDs was shown to generate more accurate estimates of genetic diversity, and of relationships within and among crop species and their wild relatives, than either data set alone. Received: 13 March 1997/Accepted: 6 May 1997  相似文献   

14.
Many neglected, underutilized species are extremely important for food production especially in Low Income Food Deficient Countries (LIFDCs). Grain amaranth is one of such crops originated and domesticated in different parts of American continent. Lack of knowledge on taxonomy and phylogenetic relationship with other related crops, analysis of the extent and distribution of genetic diversity together with work on local and traditional knowledge, are the main constrains for genetic improvement of neglected, underutilized and crop related wild species. The phylogenetic relationship and taxonomic delimitation in genus Amaranthus are still not resolved with extreme clarity. But classification of the genus Amaranthus into three subgenera viz., Acnida, Amaranthus and Albersia, based on morphological parameters is quite acceptable. Phylogenetic analysis revealed clear separation of vegetable and grain amaranths. The derivation of grain and vegetable amaranths represent two lines of descent from weed progenitor. Amaranthus hybridus L. along with grain amaranths supposed to have formed a complex in which taxonomic problems are far from being clarified, especially because of apparent common hybridization and misapplication of nomenclature. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

15.
Phylogenetic relationships in the genus Anthyllis (Leguminosae: Papilionoideae: Loteae) were investigated using data from the nuclear ribosomal internal transcribed spacer regions (ITS) and three plastid regions (psbA-trnH intergenic spacer, petB-petD region and rps16 intron). Bayesian and maximum parsimony (MP) analysis of a concatenated plastid dataset recovered well-resolved trees that are topologically similar, with many clades supported by unique indels. MP and Bayesian analyses of the ITS sequence data recovered trees that have several well-supported topological differences, both among analyses, and to trees inferred from the plastid data. The most substantial of these concerns A. vulneraria and A. lemanniana, whose placement in the parsimony analysis of the ITS data appears to be due to a strong long-branch effect. Analysis of the secondary structure of the ITS1 spacer showed a strong bias towards transitions in A. vulneraria and A. lemanniana, many of which were also characteristic of certain outgroup taxa. This may contribute to the conflicting placement of this clade in the MP tree for the ITS data. Additional conflicts between the plastid and ITS trees were more taxonomically focused. These differences may reflect the occurrence of reticulate evolution between closely related species, including a possible hybrid origin for A. hystrix. The patterns of incongruence between the plastid and the ITS data seem to correlate with taxon ranks. All of our phylogenetic analyses supported the monophyly of Anthyllis (incl. Hymenocarpos). Although they are often taxonomically associated with Anthyllis, the genera Dorycnopsis and Tripodion are shown here to be more closely related to other genera of Loteae. We infer up to six major clades in Anthyllis that are morphologically well-characterized, and which could be recognized as sections. Four of these agree with various morphology-based classifications, while the other two are novel. We reconstruct the evolution of several morphological characteristics found only in Anthyllis or tribe Loteae. Some of these characters support major clades, while others show evidence of homoplasy within Anthyllis.  相似文献   

16.
Three molecular techniques, ITS sequence analysis, random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) were used to study phylogenetic and genotypic relationships among strains of the genus Fellomyces. In the analyses were included strains isolated predominantly from epiphytic lichens collected in Indonesia, China and Mexico. The polyphasic approach indicated that the Fellomyces isolates are genotypically heterogeneous and that lichens represent a specific environment for selection of large number of the sterigmatoconidia producing species. The phylogenetic and genotypic analysis confirmed the existence of 11 currently accepted Fellomyces species and indicated that several species may be the new representatives of the genus. The RAPD and AFLP analyses demonstrated a higher potential in distinguishing the Fellomyces strains than the ITS regions. Since the sequence analysis showed low or no divergence among several strains, both RAPD and AFLP fingerprinting indicated that the strains may be discriminated at the species level.  相似文献   

17.
Abstract: Twenty-one random and 29 SSR primers were used to assess genetic variation and interrelationships among subspecies and botanical varieties of cultivated peanut, Arachis hypogaea (2n = 4x = 40), and phylogenetic relationships among cultivated peanut and wild species of the genus Arachis. In contrast with the previous generalization that peanut accessions lack genetic variation, both random and SSR primers revealed 42.7 and 54.4% polymorphism, respectively, among 220 and 124 genetic loci amplified from 13 accessions. Moreover, the dendrograms based on RAPD, ISSR, and RAPD + ISSR data precisely organized the five botanical varieties of the two subspecies into five clusters. One SSR primer was identified that could distinguish all the accessions analysed within a variety. Although the polymorphic index content varied from 0.1 to 0.5 for both ISSR and RAPD markers, primer index values were substantially higher for RAPD primers (0.35-4.65) than for SSR primers (0.35-1.73). It was possible to identify accessions, particularly those of divergent origins, by RAPD and (or) ISSR fingerprints. Based on these results, marker-based genetic improvement in A. hypogaea appears possible. None of the 486 RAPD and 330 ISSR amplification products were found to be commonly shared among 13 species of section Arachis and one species each of sections Heteranthae, Rhizomatosae, and Procumbentes. Dendrograms constructed from RAPD, ISSR, and RAPD + ISSR data showed overall similar topologies. They could be resolved into four groups corresponding to the species grouped in four taxonomic sections. The present results strongly support the view that Arachis monticola (2n = 4x = 40) and A. hypogaea are very closely related, and indicate that A. villosa and A. ipaensis are the diploid wild progenitors of these tetraploid species.  相似文献   

18.

Diversity and phylogenetic relationship between four closely related Salacia species, i.e., Salacia chinensis, Salacia macrosperma, Salacia fruticosa and Salacia oblonga, collected from the Western Ghats of Karnataka, India, was assessed. Ten each of RAPD and ISSR primers generated a total of 76 and 68 loci, generating polymorphisms of 92.21 and 89.71%, respectively. Maximum likelihood analysis of the ITS sequences revealed three clades. Dendrogram analyses of RAPD and ISSR revealed two and four clusters, respectively. Overall polymorphism revealed by RAPD was 41.45?±?10%, ISSR was 33.58?±?6.52%, and ITS was 25.50?±?17.25%. Molecular variance revealed significant variance within and among the Salacia species. Tajima’s D neutrality test and Fu’s Fs were negative for all four species, implying presences of rare alleles and population expansion. Comparative study of RAPD, ISSR and ITS for Salacia species has given an insight into the efficiency of each technique in detecting diversity within and among the population sampled in the Western Ghats of Karnataka.

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19.
Phylogenetic reconstructions with molecular tools are now widely used, thanks to advances in PCR and sequencing technologies. The choice of the molecular target still remains a problem because too few comparative data are available. This is particularly true for hybrid taxa, where differential introgression of genome parts leads to incongruity between data sets. We have studied the potential of three data partitions to reconstruct the phylogeny of mints related to M. x piperita. These included nuclear DNA (ITS), chloroplast DNA (non-coding regions trnL intron, intergenic spacers trnL-trnF, and psbA-trnH), and AFLP and ISSR, markers. The taxonomic sampling was composed of hybrids, diploid and polyploid genomes. Since the genealogy of cultivated mint hybrids is known, they represent a model group to compare the usefulness of various molecular markers for phylogeny inference. Incongruities between ITS, chloroplast DNA, and AFLP-ISSR phylogenetic trees were recorded, although DNA fingerprinting data were congruent with morphological classification. Evidence of chloroplast capture events was obtained for M. x piperita. Direct sequencing of ITS led to biased results because of the existence of pseudogenes. Sequencing of cloned ITS further failed to provide evidence of the existence of the two parental copy types for M. x piperita, a sterile hybrid that has had no opportunity for concerted evolution of ITS copies. AFLP-ISSR data clustered M. x piperita with the parent that had the largest genome. This study sheds light on differential of introgression of different genome regions in mint hybrids.  相似文献   

20.
Nucleotide sequences of a chloroplast rDNA region including 8 bp from the 3" end of 23S rDNA–ITS2–4.5S rDNA–ITS3–5S rDNA–ITS4 (approximately 800 bp) were determined in 25 species of Lycopodiaceae and two species of the genus Isoetes. The rate of molecular evolution of spacers significantly varied in different Lycopsida taxa. A phylogenetic analysis by the neighbor-joining (NJ) method revealed that the family Lycopodiaceae is monophyletic. The topology of phylogenetic trees suggests the isolation of four or probably five genera in family Lycopodiaceae. For these genera, synapomorphic indels were detected. The obtained data were compared with the results of phylogenetic analysis of Lycopsida with regard to other sequences. The relationships of taxa within the family Lycopodiaceae is discussed.  相似文献   

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