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1.
The molecular diversity among 60 isolates of Renibacterium salmoninarum which differ in place and date of isolation was investigated by using randomly amplified polymorphic DNA (RAPD) analysis. Isolates were grouped into 21 banding patterns which did not reflect the biological source. Four 16S-23S rRNA intergenic spacer (ITS1) sequence variations and two alleles of an exact tandem repeat locus, ETR-A, were the bases for formation of distinct groups within the RAPD clusters. This study provides evidence that the most common ITS1 sequence variant, SV1, possesses two copies of a 51-bp repeat unit at ETR-A and has been widely dispersed among countries which are associated with mainstream intensive salmonid culture.  相似文献   

2.
Nucleotide sequences of the internal transcribed spacer 1 (ITS1)–5.8S–ITS2 region of the nuclear ribosomal RNA gene were determined in the white-backed planthopper (WBPH) Sogatella furcifera (Horváth) to detect molecular variation among regional populations in Asia. We analyzed 932 sequences from 172 individuals (4–9 clones per individual) of 33 populations collected in 1987–2008 from six countries, Japan, China, Taiwan, Vietnam, Philippines, and Papua New Guinea. WBPH showed intra-individual variation in ITS1, which is mainly attributable to the frequency (0–10) of the 66-bp repeat sequence in ITS1. Among the examined clones, the sequences of 5.8S were mostly identical and those of ITS2 were similar. A single planthopper had a maximum of 6 different variants in the number of ITS1 repeats, suggesting highly varied repeat numbers in individual planthoppers. The ITS1 with four repeats was the most frequently (64%) detected. Such a repeat was not observed in two other economically important planthopper species, Nilaparvata lugens (Stål) and Laodelphax striatellus (Fallén). The ITS nucleotide sequences in the WBPH populations in Asia were genetically close and some variations in the sequences were not related to regional populations, indicating that the nucleotide sequences of the ITS region are not useful for geographical discrimination of the WBPH. This closeness seems to be caused by long distance migration and genetic exchange among populations.  相似文献   

3.
The most important and well-known medicinal plant among ~400 species of the genus Aloe is Aloe vera. It is widely used in pharmaceutical, cosmetic, and food industries. Identification and assessment of genetic relationship among the populations and cultivars is needed for conservation and sustainable utilization of this commercially important plant. DNA fingerprinting with random amplified polymorphic DNA (RAPD) marker and Internal Transcribed Spacer (ITS1 and ITS2) of ribosomal DNA sequence analysis were carried out to assess the genetic diversity among populations of Aloe vera collected from geographically different four districts of West Bengal and Jodhpur, Rajasthan. RAPD profiles yielded 158 amplicons showing ~87.34% polymorphism. Analyses of ITS sequences showed that in contrast to ITS2, the length and %GC content (53.6–77.3%) of ITS1 varied within populations. Multiple sequence alignment data reveal that substitutions, insertions, and deletions have arisen at various positions in the ITS regions suggesting polymorphism. A 5′-GGCGCGATGGGCGCCAAGGAA-3′ sequence in ITS1 is conserved in all populations, except AvS4. RAPD dendrogram and topologies of the NJ, Parsimony and ML tree generated from ITS1 sequence revealed that there is a close genetic similarity among AvS1, AvS4, and AvS7 populations. These genetic studies may contribute to plant improvement programs of A. vera.  相似文献   

4.
根据ITS1-5.8S-ITS2区域的特异核酸序列变化,加特隐球酵母Cryptococcus gattii(≡新型隐球酵母加特变种Cryptococcu neoformans var.gattii)可分为6种基因型。本研究通过检测加特隐球酵母的IGS基因,发现其IGS序列有着更丰富的变异和信息位点。通过结合加特隐球酵母RAPD(随机扩增的多态性DNA)图谱比较研究,与IGS和ITS的序列分析结果大体一致,说明新近发现的加特隐球酵母ITS8型确实有别于以前报道过的其他加特隐球酵母ITS基因型。研究证明IGS1及IGS2基因片段分析可以作为加特隐球酵母基因分类鉴定中有效的辅助鉴别的分子生物学方法,联合多种基因分类鉴定的方法可以更有效地揭示新型隐球酵母加特变种种内不同基因亚型间的遗传进化关系。  相似文献   

5.
Genotypic Diversity among Brazilian Isolates of Sclerotium rolfsii   总被引:1,自引:0,他引:1  
Thirty isolates of Sclerotium rolfsii Sacc. from different hosts and regions of Brazil were studied in relation to morphology, mycelial compatibility, analysis of genomic DNA through random amplified polymorphic DNA (RAPD), variation within the nuclear rDNA [internal transcribed spacers (ITS)] and sequencing of ITS fragments. There was considerable variability among isolates in relation to the number, size and location of sclerotia on the medium surface. Thirteen mycelial compatibility groups (MCG) were identified among 23 isolates. Seven isolates were only self‐compatible. With the exception of group 3, where all the isolates came from soybean, there was no apparent correlation between group and isolate origin. On the basis of RAPD profiles, 11 haplotypes (A to K) were identified. There was an association between the RAPD groups and MCG. Haplotypes A, B, D, G, I and K belonged to MCG groups 1, 2, 3, 4, 5 and 6, respectively. All other RAPD haplotypes contained incompatible isolates. Polymerase chain reaction (PCR) amplification with primers 4R and 5F amplified two fragments containing ITS1, ITS2 and 5.8 S rDNA sequences, that were present in all isolates, with molecular sizes of 739 and 715 bp. Restriction analysis of PCR products showed that the two fragments had sequence divergency which is referred to as ‘ITS types’. Four arbitrarily chosen soybean isolates (2, 6, 7 and 23) and two non‐soybean isolates (11 and 22) were used to investigate the variation within the ITS sequence and its role in the phylogeny. The strict consensus of nine most‐parsimonious trees inferred from the data set which included six isolates of S. rolfsii, four of which have two different ‘ITS types’, showed three well‐supported groupings. The neighbour‐joining tree inferred from the data set also showed three major clades as did the parsimony tree. The major difference was that in the neighbour‐joining tree the ‘ITS type’ 11 was resolved and grouped in one clade. These results show that the ‘ITS types’ within isolates are almost always phylogenetically distinct. There was no clear correlation between ITS‐based phylogeny and isolate origin.  相似文献   

6.
The phylogenetic relationships among the three species of Tinospora found in India are poorly understood. Morphology does not fully help to resolve the phylogeny and therefore a fast approach using molecular analysis was explored. Two molecular approaches viz Random Amplified Polymorphic DNA (RAPD) assay and restriction digestion of ITS1-5.8S-ITS2 rDNA (PCR-RFLP) were used to evaluate the genetic similarities between 40 different accessions belonging to three species. Of the 38 random primers used only six generated the polymorphism, while as three out of 11 restriction enzymes used gave polymorphic restriction patterns. The average proportion of polymorphic markers across primers was 95%, however restriction endonucleases showed 92% polymorphism. RAPD alone was found suitable for the species diversions. In contrast PCR- RFLP showed bias in detecting exact species variation. The correlation between the two markers was performed by Jaccard's coefficient of similarity. A significant (r= 0.574) but not very high correlation was obtained. Further to authenticate the results obtained by two markers, sequence analysis of ITS region of ribosomal DNA (ITS1 and ITS2, including 5.8S rDNA) was performed. Three independent clones of each species T. cordifolia, T. malabarica and T. crispa were sequenced. Phylogenetic relationship inferred from ITS sequences is in agreement with RAPD data.  相似文献   

7.
A southern Spanish massif (Tejeda/Almijara range, Málaga province, SE Spain) has been previously identified as a contact zone for genotypes of a rare taxon,Armeria villosa subsp.bernisii, and a frequent one,A. filicaulis, based on (1) the discovery of a species-independent geographically structured pattern of variation for nuclear ribosomal ITS sequence data, and (2) the sharing of chloroplast haplotypes, which reveal horizontal transfer between the species. This study uses RAPD data, as a total DNA marker, and morphometrics, as potentially revealing hybridization and introgression, to throw further light on the origin of the above mentioned contact zone. Individuals of the two taxa sampled from the range do not show a F1 hybrid profile for RAPD or for morphometrics. To integrate these results with the previously published sequence data (ITS and chloroplast spacertrnL-F) it is proposed that introgressive hybridization has occurred inA. villosa subsp.bernisii, whereas forA. filicaulis the contact zone occurs at the intraspecific level. With the available data, the contact between individuals ofArmeria with different genotypes in the two taxa may have implied westward migration from a biodiverse massif like Sierra Nevada, and this may apply to other organisms although further data are needed to confirm it.  相似文献   

8.
The genetic variability and relationships among 20 Mangifera indica genotypes representing 15 endangered and 5 cultivars, obtained from Indian Gir forest region, were analyzed using 10 random amplified polymorphic DNA (RAPD) and 21 inter simple sequence repeat (ISSR) markers. RAPD markers were more efficient than the ISSR assay with regards to polymorphism detection. Also, the average numbers of polymorphic loci per primer, average polymorphic information content (PIC) and primer index (PI) values were more for RAPD than for ISSR. But, total number of genotype specific marker loci, Nei’s genetic diversity (h), Shannon’s information index (I), total heterozygosity (Ht), average heterozygosity (Hs) and mean coefficient of gene differentiation (Gst) were more for ISSR as compared to RAPD markers. The regression test between the two Nei’s genetic diversity indexes showed low regression between RAPD and ISSR based similarities but maximum for RAPD and RAPD + ISSR based similarities. The pattern of clustering of genotypes within groups was not similar when RAPD and ISSR derived dendrogram were compared. Thus, both the markers were equally important for genetic diversity analysis in M. indica.  相似文献   

9.
Wang P  Lu Y  Zheng M  Rong T  Tang Q 《PloS one》2011,6(4):e16728
Genetic relationship of a newly discovered teosinte from Nicaragua, Zea nicaraguensis with waterlogging tolerance, was determined based on randomly amplified polymorphic DNA (RAPD) markers and the internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA using 14 accessions from Zea species. RAPD analysis showed that a total of 5,303 fragments were produced by 136 random decamer primers, of which 84.86% bands were polymorphic. RAPD-based UPGMA analysis demonstrated that the genus Zea can be divided into section Luxuriantes including Zea diploperennis, Zea luxurians, Zea perennis and Zea nicaraguensis, and section Zea including Zea mays ssp. mexicana, Zea mays ssp. parviglumis, Zea mays ssp. huehuetenangensis and Zea mays ssp. mays. ITS sequence analysis showed the lengths of the entire ITS region of the 14 taxa in Zea varied from 597 to 605 bp. The average GC content was 67.8%. In addition to the insertion/deletions, 78 variable sites were recorded in the total ITS region with 47 in ITS1, 5 in 5.8S, and 26 in ITS2. Sequences of these taxa were analyzed with neighbor-joining (NJ) and maximum parsimony (MP) methods to construct the phylogenetic trees, selecting Tripsacum dactyloides L. as the outgroup. The phylogenetic relationships of Zea species inferred from the ITS sequences are highly concordant with the RAPD evidence that resolved two major subgenus clades. Both RAPD and ITS sequence analyses indicate that Zea nicaraguensis is more closely related to Zea luxurians than the other teosintes and cultivated maize, which should be regarded as a section Luxuriantes species.  相似文献   

10.
Niu Q  Luo J  Guan G  Liu Z  Ma M  Liu A  Gao J  Ren Q  Li Y  Qiu J  Yin H 《Experimental parasitology》2009,121(1):64-68
The first and second internal transcribed spacers (ITS1, ITS2) as well as the intervening 5.8S coding region of the rRNA gene for six Babesia spp. isolated from different geographic origins were characterized. Varying degrees of ITS1 and ITS2 intra- and inter-species sequence polymorphism were found among these isolates. Phylogenetic analysis of the ITS1-5.8S gene-ITS2 region clearly separated the isolates into two clusters. One held an unidentified Babesia sp. transmitted by Hyalomma anatolicum anatolicum. The second held five other isolates, which were considered to be Babesia motasi. Each Babesia species cluster possessed ITS1 and ITS2 of unique size(s) and species specific nucleotide sequences. The results showed that ITS1, ITS2 and the complete ITS1-5.8S-ITS2 region could be used to discriminate these ovine Babesia spp. effectively.  相似文献   

11.
Lentil (Lens culinaris ssp. culinaris), is a self-pollinating diploid (2n?=?2x?=?14), cool-season legume crop and is consumed worldwide as a rich source of protein (~24.0%), largely in vegetarian diets. Here we report development of a genetic linkage map of Lens using 114 F2 plants derived from the intersubspecific cross between L 830 and ILWL 77. RAPD (random amplified polymorphic DNA) primers revealed more polymorphism than ISSR (intersimple sequence repeat) and SSR (simple sequence repeat) markers. The highest proportion (30.72%) of segregation distortion was observed in RAPD markers. Of the 235 markers (34 SSR, 9 ISSR and 192 RAPD) used in the mapping study, 199 (28 SSRs, 9 ISSRs and 162 RAPDs) were mapped into 11 linkage groups (LGs), varying between 17.3 and 433.8 cM and covering 3843.4 cM, with an average marker spacing of 19.3 cM. Linkage analysis revealed nine major groups with 15 or more markers each and two small LGs with two markers each, and 36 unlinked markers. The study reported assigning of 11 new SSRs on the linkage map. Of the 66 markers with aberrant segregation, 14 were unlinked and the remaining 52 were mapped. ISSR and RAPD markers were found to be useful in map construction and saturation. The current map represents maximum coverage of lentil genome and could be used for identification of QTL regions linked to agronomic traits, and for marker-assisted selection in lentil.  相似文献   

12.
Recent advances in molecular biology have enabled the genotyping of individual nematodes, facilitating the analysis of genetic variability within and among plant-pathogenic nematode isolates. This review first describes representative examples of how RFLP, RAPD, AFLP, and DNA sequence analysis have been employed to describe populations of several phytonematodes, including the pinewood, burrowing, root-knot, and cyst nematodes. The second portion of this paper evaluates the utility of a size-variable mitochondrial DNA locus to examine the genetic structure of Meloidogyne isolates using two alternate methodologies, variable number tandem repeat (VNTR) and repeat associated poiymorphism (RAP) analysis. VNTR analysis has revealed genetic variation among individual nematodes, whereas RAP may provide useful markers for species and population differentiation.  相似文献   

13.
Genetic diversity among 27 isolates (23 from chickpea and 4 from other host crops) of Rhizoctonia bataticola representing 11 different states of India was determined by random amplified polymorphic DNA (RAPD), internal transcribed spacer restriction fragment length polymorphism (ITS-RFLP) and ITS sequencing. The isolates showed variability in virulence test. Unweighted paired group method with arithmetic average cluster analysis was used to group the isolates into distinct clusters. The clusters generated by RAPD grouped all the isolates into six categories at 40% genetic similarity. High level of diversity was observed among the isolates of different as well as same state. Some of the RAPD (OPN 4, OPN 12, and OPN 20) markers clearly distinguished majority of the isolates into the area specific groups. The ITS I, 5.8rDNA and ITS II regions of 11 isolates representing different RAPD groups were amplified with primers ITS 1 and ITS 4 and digested with seven restriction enzymes. The restriction enzymes DraI, MboI, RsaI, and AluI were found to be suitable for differentiating the isolates into five categories by showing isolate specific ITS-RFLP patterns. The isolates were variable in their nucleotide sequences of the ITS regions. This is the first study on genetic diversity among chickpea isolates of R. bataticola.  相似文献   

14.
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   

15.
Random Amplified Polymorphic DNA (RAPD), inter simple sequence repeat (ISSR) and Amplified Fragment Length Polymorphism (AFLP) profiling were evaluated for assessing the extent of genetic variation among the isolates of Ustilago tritici (Pers.) Rostr., which causes the loose smut disease of wheat.Thirty random decamer primers, six random primer pairs, four SSR primers such as (GACA)4, (GATA)4, (CAA)5 and (GTG)5 and nine combinations of AFLP selective primers were used to characterize nine isolates of the fungus. These isolates were collected from infected earheads of seven commercial wheat cultivars grown at eight different locations in Haryana, which is a major wheat growing state in the North-West Plain Zone of India. The RAPD and ISSR primers generated 21 0 scorable amplified fragments, all of which were monomorphic among the isolates.The AFLP primer combinations generated 239 fragments out of which 193 were polymorphic. All the isolates could be precisely differentiated from each other employing AFLP and grouped into two distinct clusters.The molecular classification partly corresponded with geographic distribution and host origin of the isolates. AFLP profiling was found superior to RAPD and ISSR and can be effectively utilized for further characterization of loose smut pathogen.  相似文献   

16.
Six geographic isolates of Heterodera avenae, including two isolates each from Sweden, Australia, and the United States, were compared on the basis of 2-D PAGE protein patterns and the complete DNA sequence for the two internal transcribed ribosomal DNA spacers (rDNA ITS1 and ITS2) and the 5.8S rRNA gene. The protein pattern data and rDNA ITS sequence data both indicated that the Swedish Gotland strain of H. avenae differed markedly from the rest of the isolates. Protein patterns for the Australia isolates differed more from a Swedish strict H. avenae isolate and isolates from Oregon and Idaho, than the two U.S. isolates and the Swedish strict H. avenae isolate differed from each other. Except for the Gotland strain isolate, the rDNA ITS sequences were highly conserved among all of the H. avenae isolates, just as we earlier found them to be conserved among species of the schachtii group of Heterodera.  相似文献   

17.
The internal transcribed spacer (ITS) region of the 18 S–25 S nuclear ribosomal DNA repeat was sequenced from 19 populations of the tribeLactuceae, including all species of dwarf dandelion (Krigia) and five outgroup genera. The incidence of length changes and base substitutions was at least two times higher for ITS 1 than ITS 2. Interspecific sequence divergence withinKrigia averaged 9.62% (1.61%–15.19%) and 4.26% (0%–6.64%) in ITS 1 and ITS 2, respectively. Intergeneric sequence divergence ranged from 15.6% to 44.5% in ITS 1 and from 8.0% to 28.6% in ITS 2. High sequence divergence and homoplasy among genera of tribeLactuceae suggest that the phylogenetic utility of ITS sequence data is limited to interspecific studies or comparisons among closely related genera. Trees generated from ITS sequences are essentially identical to those from restriction site comparisons of the entire nuclear ribosomal (nr) DNA region. The degree of tree resolution differed depending on how gaps were treated in phylogenetic analyses. The ITS trees were congruent with the chloroplast DNA and morphological phylogenies in three major ways: 1) the sister group relationship betweenKrigia andPyrrhopappus; 2) the recognition of two monophyletic sections,Krigia andCymbia, in genusKrigia; and 3) the monophyly of theK. occidentalis-K. cespitosa clade in sect.Cymbia. However, the two nrDNA-based trees are not congruent with morphology/chloroplast DNA-based trees for the interspecific relationships in sect.Krigia. An average of 22.5% incongruence was observed among fourKrigia data sets. The relatively high degree of incongruence among data sets is due primarily to conflict between trees based on nrDNA and morphological/cpDNA data. The incongruence is probably due to the concerted evolution of nrDNA repeating units. The results fromKrigia and theLactuceae suggest that nrDNA data may have limited utility in phylogenetic studies of plants, especially in groups which exhibit high levels of sequence divergence. Our combined phylogenetic analysis as a total evidence shows the least conflict to each of the individual data sets.  相似文献   

18.
The nucleotide sequence of the 5.8S rRNA gene and the flanked internal transcribed spacer (ITS) regions of six Trichomonas vaginalis isolates with different metronidazole sensitivity and geographic origin were genotyped. A multiple sequence alignment was performed with different sequences of other isolates available at the GenBank/EMBL/DDBJ databases, which revealed 5 different sequence patterns. Although a stable mutation in position 66 of the ITS1 (C66T) was observed in 26% (9/34) of the T. vaginalis sequences analyzed, there was 99.7% ITS nucleotide sequence identity among isolates for this sequence. The nucleotide sequence variation among other species of the genus Trichomonas ranged from 3.4% to 9.1%. Surprisingly, the % identity between T. vaginalis and Pentatrichomonas hominis was ~ 83%. There was > 40% divergence in the ITS sequence between T. vaginalis and Tritrichomonas spp., including Tritrichomonas augusta, Tritrichomonas muris, and Tritrichomonas nonconforma and with Tetratrichomonas prowazeki. Dendrograms grouped the trichomonadid sequences in robust clades according to their genera. The absence of nucleotide divergence in the hypervariable ITS regions between T. vaginalis isolates suggests the early divergence of the parasite. Importantly, these data show this ITS1-5.8S rRNA-ITS2 region suitable for inter-species differentiation.  相似文献   

19.
In this study, we have aimed to genetically characterize Ginkgo biloba. Nine G. biloba samples from different places of China were collected, and DNA was extracted from the leaves of these samples for inter-simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) analysis. ISSR analysis showed high genetic variation among the nine varieties of G. biloba; the polymorphism and similarity coefficients were 87% and 0.40–0.84, respectively. RAPD analysis also showed 93% polymorphism, and the similarity coefficients ranged from 0.44 to 0.87. Persistent genetic isolation that developed for millions of years might influence the genetic variability between the samples of G. biloba. This study generates a genetic map of G. biloba, and reports the highly variable intra-species genetic characteristics of this living fossil among different geographical locations of China. Our study also suggests that ISSR and the improved RAPD markers are useful molecular tools for the genetic characterization of plants.  相似文献   

20.
Pleurotus pulmonarius is one of the most widely cultivated and popular edible fungi in the genus Pleurotus. Three molecular markers were used to analyze the genetic diversity of 15 Chinese P. pulmonarius cultivars. In total, 21 random amplified polymorphic DNA (RAPD), 20 inter-simple sequence repeat (ISSR), and 20 sequence-related amplified polymorphism (SRAP) primers or primer pairs were selected for generating data based on their clear banding profiles produced. With the use of these RAPD, ISSR, and SRAP primers or primer pairs, a total of 361 RAPD, 283 ISSR, and 131 SRAP fragments were detected, of which 287 (79.5 %) RAPD, 211 (74.6 %) ISSR, and 98 (74.8 %) SRAP fragments were polymorphic. Unweighted Pair-Group Method with Arithmetic Mean (UPGMA) trees of these three methods were structured similarly, grouping the 15 tested strains into four clades. Subsequently, visual DNA fingerprinting and cluster analysis were performed to evaluate the resolving power of the combined RAPD, ISSR, and SRAP markers in the differentiation among these strains. The results of this study demonstrated that each method above could efficiently differentiate P. pulmonarius cultivars and could thus be considered an efficient tool for surveying genetic diversity of P. pulmonarius.  相似文献   

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