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1.
Genetic variability in the wild genotypes of Dendrobium nobile Lindl. collected from different parts of Northeast India, was analyzed using a Start Codon Targeted (SCoT) marker system. A total of sixty individuals comprising of six natural populations were investigated for the existing natural genetic diversity. One hundred and thirty two (132) amplicons were produced by SCoT marker generating 96.21% polymorphism. The PIC value of the SCoT marker system was 0.78 and the Rp values of the primers ranged between 4.43 and 7.50. The percentage of polymorphic loci (Pp) ranging from 25% to 56.82%, Nei's gene diversity (h) from 0.08 to 0.15 with mean Nei's gene diversity of 0.28, and Shannon's information index (I) values ranging from 0.13 to 0.24 with an average value of 0.43 were recorded. The gene flow value (0.37) and the diversity among populations (0.57) demonstrated higher genetic variation among the populations. Analysis of molecular variance (AMOVA) showed 43.37% of variation within the populations, whereas 56.63% variation was recorded among the populations. Cluster analysis also reveals high genetic variation among the genotypes. Present investigation suggests the effectiveness of SCoT marker system to estimate the genetic diversity of D. nobile and that it can be seen as a preliminary point for future research on the population and evolutionary genetics of this endangered orchid species of medicinal importance.  相似文献   

2.
Genetic variation and relationships among 37 cultivars of Ziziphus mauritiana (Lamk.) native of India were analyzed using start codon targeted (SCoT), inter-simple sequence repeats (ISSR), and ribosomal DNA (rDNA) markers. High level of polymorphism among SCoT (61.6%) and ISSR (61%) primers with higher PIC values ranging from 63.1 to 90.4% of SCoT and 47.3 to 88.8% of ISSR primers was recorded. SCoT and ISSR dendrograms revealed similarity coefficients ranging from 0.80 to 0.92 and 0.79 to 0.96, respectively, and clearly delineated all the cultivars of Z. mauritiana into well-supported distinct clusters. Greater Gst signifies higher amount of differentiation observed over multiple loci among seven Z. mauritiana populations. On the other hand, higher gene flow demonstrating a very high migration rate between Z. mauritiana populations indicated higher rates of transfer of alleles or genes from one population to another. The genetic diversity of population 1 (Rajasthan) was the richest among all the seven populations. The largest genetic distance was measured between Maharashtra and West Bengal and the least between Rajasthan and Punjab cultivars. Most of the genetic diversity exists within population rather than among populations. Substantial variation in the ITS-1 region signifies its phylogenetic utility specifically in assessing genetic diversity in Z. mauritiana. The clustering patterns using three molecular marker systems vis-à-vis place of origin exhibited no consistency in grouping of Z. mauritiana cultivars as cultivars from the same place of origin were genetically cataloged into different SCoT, ISSR, and ITS phylogram clusters indicating wide genetic diversity and distribution across agro-climatic zones validating the robustness of marker systems tested.  相似文献   

3.
Kumar  Deepender  Chhokar  Vinod  Sheoran  Sonia  Singh  Rajender  Sharma  Pradeep  Jaiswal  Sarika  Iquebal  M. A.  Jaiswar  Akanksha  Jaisri  J.  Angadi  U. B.  Rai  Anil  Singh  G. P.  Kumar  Dinesh  Tiwari  Ratan 《Molecular biology reports》2020,47(1):293-306

Genetic diversity is crucial for successful adaptation and sustained improvement in crops. India is bestowed with diverse agro-climatic conditions which makes it rich in wheat germplasm adapted to various niches. Germplasm repository consists of local landraces, trait specific genetic stocks including introgressions from wild relatives, exotic collections, released varieties, and improved germplasm. Characterization of genetic diversity is done using morpho-physiological characters as well as by analyzing variations at DNA level. However, there are not many reports on array based high throughput SNP markers having characteristics of genome wide coverage employed in Indian spring wheat germplasm. Amongst wheat SNP arrays, 35K Axiom Wheat Breeder’s Array has the highest SNP polymorphism efficiency suitable for genetic mapping and genetic diversity characterization. Therefore, genotyping was done using 35K in 483 wheat genotypes resulting in 14,650 quality filtered SNPs, that were distributed across the B (~?50%), A (~?39%), and D (~?10%) genomes. The total genetic distance coverage was 4477.85 cM with 3.27 SNP/cM and 0.49 cM/SNP as average marker density and average inter-marker distance, respectively. The PIC ranged from 0.09 to 0.38 with an average of 0.29 across genomes. Population structure and Principal Coordinate Analysis resulted in two subpopulations (SP1 and SP2). The analysis of molecular variance revealed the genetic variation of 2% among and 98% within subpopulations indicating high gene flow between SP1 and SP2. The subpopulation SP2 showed high level of genetic diversity based on genetic diversity indices viz. Shannon’s information index (I)?=?0.648, expected heterozygosity (He)?=?0.456 and unbiased expected heterozygosity (uHe)?=?0.456. To the best of our knowledge, this study is the first to include the largest set of Indian wheat genotypes studied exclusively for genetic diversity. These findings may serve as a potential source for the identification of uncharacterized QTL/gene using genome wide association studies and marker assisted selection in wheat breeding programs.

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4.
Genetic diversity existing amongst five Eulophia orchid species were assessed using start codon targeted polymorphism (SCoT) and inter-retrotransposon amplified polymorphism (IRAP) markers. A total of 12 SCoT and 5 IRAP markers revealed an average of 63% genetic variability [SCoT?=?63.87; IRAP?=?64.95%] amongst the five Eulophia species investigated. The genetic similarities were assessed using both UPGMA and Bayesian approaches which indicated identical clustering patterns at a genetic similarity level of 50%. Analysis of molecular variance (AMOVA) revealed the presence of a significant degree of genetic variability, mostly compartmentalized within the species level. Amongst the five assessed Eulophia species, E. parviflora was the most genetically diverse representative whereas E. welwitschii was found to be least diverse based on a comparative assessment of various population genetic parameters like Nei’s gene diversity (h) and Shannon’s information index (I) with an overall gene flow value greater than 1. In order to evaluate the comparative marker efficiency, SCoT and IRAP marker data were subjected to various benchmark analyses like marker index, resolving power, polymorphic index content, multiplex ratio and effective multiplex ratio which revealed the robustness of both the marker techniques in assessment of genetic diversity. The present report provides the first molecular insights into the aspects of inter and intra specific genetic variability in medicinally as well as horticulturally important Eulophia species along with addressing their conservation concerns. In a nutshell, the present approach is simple, rapid and cost effective and can be extended for analysis of genetic diversity of other related plant species.  相似文献   

5.
Start Codon Targeted markers were used to establish phylogenetic relationship among seven species from Citrus L. genus. Twelve SCoT primers were used for their ability to reveal polymorphism of the targeted codon of initiation. A total of 132 amplicons were generated and 93.9% of them were polymorphic. The polymorphism information content of 0.884 and the resolving power of 75.22 illustrate the efficiency of the tested SCoT primers in highlighting polymorphism. The average Nei's (1973) gene diversity (0.376), the Schannon's index (0.548) and the Gst parameter (0.346) describe an important polymorphism at the interspecies level in Citrus genus. Analysis of molecular variance suggested significant genetic differences within species. In fact, 84% of variance occurs within the species, whereas 16% of the variation was recorded among the species of Citrus. The limited gene flow (Nm = 0.941) was recognized as a major factor to explain the partition of the observed diversity. The principal coordinates analyses, Neighbor Joining and the Bayesian clustering approach based on the SCoT markers also confirm the discrimination of the species of Citrus. Our results confirm the relevance and suggest the effectiveness of the SCoT markers for assessing genetic diversity, characterization and identification of the species of Citrus.  相似文献   

6.
Inter-simple sequence repeat (ISSR) markers were used to analyze genetic diversity and relatedness of 15 germplasms of Fagopyrum tataricum. Samples representing 75 individuals were collected from a range of altitudes in the Western Himalaya. The 13 ISSR primers revealed 98.1% polymorphism among populations, whereas average polymorphism was extremely low (2.18%) within populations. The coefficient of population differentiation was 0.9750, with limited gene flow (N m) of 0.0128. The average PIC value of the ISSR markers was high (0.812), with a marker ratio of 0.65 and marker index of 6.66. The genetic diversity of F. tataricum significantly correlated with altitude and gene diversity, Shannon’s index, and the percentage of polymorphic bands. The genetic diversity among populations showed broad genetic base and provided a developmental strategy for crop improvement.  相似文献   

7.
A molecular assessment of genetic diversity was performed on a set of 228 selected accessions belonging to the different Aegilops and Triticum species using CAAT-box derived polymorphism (CBDP) markers. Fifteen CBDP primers generated 141 polymorphic fragments with an average of 9.40 per primer. The average of polymorphic information content and resolving power revealed a high efficiency of CBDP markers in analyzing genetic diversity among different wheat genotypes. The diversity indexes including polymorphic loci percent, number of observed and effective alleles, Shannon’s index and gene diversity among different populations were 76.24%, 1.67, 1.49, 0.42 and 0.28, respectively. These essentially coincided with the analysis of molecular variance results, indicating that 86, 68, and 59.46% of genetic variation were found within two Aegilops and Triticum genera and their populations, respectively. Genetic relationships inferred from cluster analysis was matched with STRUCTURE analysis, disclosing the accessions were grouped based on their genomic constitution. Furthermore, these results were confirmed by principal coordinate analysis (PCoA). Taken together, our results suggest that CBDP markers will be useful for genetic diversity assessment in the domesticated and wild relatives of wheat.  相似文献   

8.
Selection of milk thistle (Silybum marianum (L.) Gaertn.) genotypes for commercial cultivation depends on wild population resources, rather than on selection of varieties. The evaluation of these populations could contribute to the development of new milk thistle varieties with desirable traits such as high silymarin content. Therefore, we conducted a study to evaluate 30 wild populations occurring naturally in Greece, based on seed silymarin content. Seeds were collected from populations growing in localities presenting different environmental conditions. In addition, we also investigated the diversity in levels of silymarin constituents, as well as observed correlations among them. Significant differences in silymarin content were recorded among the populations studied, with values ranging from 2.31 to 7.71% (avg. 3.31%), as well as in flavonolignan and taxifolin content. The mean taxifolin content was 4.96 mg/g, while the highest silybin A + silybin B content (21.77–31.39 mg/g of dry weight (dw)) was recorded in seeds from the “Spata” population originating from central Greece. Our results showed noticeable levels of diversity in silymarin content and composition in native milk thistle populations, indicating that a valuable gene pool for exploitation in milk thistle breeding programmes exists in Greece.  相似文献   

9.
本研究利用SCoT标记对96份柳枝稷种质的亲缘关系和遗传变异进行了研究。筛选出20条引物对96份供试材料进行PCR扩增,共获得445条带,其中多态性条带402条,平均多态性条带比率(PPB)达90.31%,多态性信息含量(PIC)为0.166~0.410,平均值为0.332,标记指数(MI)为10.20。遗传相似系数(GS)为0.498~0.912,平均值为0.688。表明SCoT标记能够揭示柳枝稷种质间的遗传变异。通过UPGMA分析表明,96份种质资源聚为高地型和低地型两大类。经POPGENE1.32软件分析结果显示:96份柳枝稷基因多样性指数(H)为0.285,Shannon指数(I)为0.431,表明供试的种质间遗传多样性丰富,遗传多样性水平高。经AMOVA 1.55方差分析揭示:96份柳枝稷生态型内的遗传变异占总变异的72.85%,生态型间遗传变异占总变异的27.15%,结果表明ScoT可用于柳枝稷遗传多样性研究,该研究结果可为柳枝稷种质资源的进一步开发利用提供重要信息。  相似文献   

10.
Polygonati rhizoma (PR) is an important and widely used product in Chinese traditional medicine and edible goods. The time-consuming nature of breaking dormancy in both rhizomes and seeds means that improving variety selection is limited to collection, identification, and selection of germplasms. In this study, we used two DNA-based molecular marker techniques—inter simple sequence repeat (ISSR) and start codon targeted (SCoT)—to assess the genetic diversity and population structure among PR source plants collected from 47 different regions and belonging to 12 populations (P1–P12). For molecular markers analysis, 15 ISSR and 10 SCoT markers were tested. Total number of 159 fragments (150–4000 bp) were amplified based on ISSR analysis with a range from 6 to 17 bands, 153 of them were polymorphic, ranging from 97.27 to 100%. For SCoT analysis, 164 polymorphic bands (150–5000 bp) were observed, varying from 14 to 19 bands for each primer. Nei’s genetic diversity analysis showed that the highest value was found in P11 for ISSR and P4 for SCoT markers. The highest Nei’s genetic diversity value was observed in P5 for combined markers and the low in P2. Nei’s dendrogram constructed with combined markers indicated a 75–89% of genetic similarity coefficient among populations. Population structure analysis revealed an optimum number of three groups, the same as their geographical distribution. This knowledge on PR genetic diversity can be used in future breeding programs, genetic improvement, product enhancement, and germplasms conservation.  相似文献   

11.
Persian oak (Quercus brantii Lindl.) is one of the most important woody species of the Zagros forests in Iran. Three molecular marker techniques: start codon targeted (SCoT), inter-simple sequence repeat (ISSR) and inter-retrotransposon amplified polymorphism (IRAP) markers were compared for fingerprinting of 125 individuals of this species collected from different geographical locations of north-west of Iran. A total of 233 bands were amplified by 18 ISSR primers, of which 224 (96.10%) were polymorphic, and 126 polymorphic bands (97.65%) were observed in 129 bands amplified by 10 IRAP primers. Besides, 118 bands were observed for all 10 SCoT primers, of which 113 were polymorphic (95.71%). Average polymorphism information content (PIC) for ISSR, IRAP and SCoT markers was 0.30, 0.32 and 0.38, respectively, and this revealed that SCoT markers were more informative than IRAP and ISSR for the assessment of diversity among individuals. Based on the three different molecular types, cluster analysis revealed that 125 individuals taken for the analysis can be divided into three distinct clusters. The Jaccard's genetic similarity based on the combined data ranged from 0.23 to 0.76. These results suggest that efficiency of SCoT, IRAP and ISSR markers was relatively the same in fingerprinting of individuals. All molecular marker types revealed a low genetic differentiation among populations, indicating the possibility of gene flow between the studied populations. These results have an important implication for Persian oak (Q. brantii) germplasm characterization, improvement, and conservation.  相似文献   

12.
Sequence-related amplified polymorphism (SRAP) was used to assess the genetic diversity of 63 cultivated, wild, and ornamental pomegranate genotypes from five different geographical regions of Iran. A total of 250 fragments were amplified using 13 primer combinations; among these, 133 bands (53?%) were polymorphic. The average PIC value was 0.28 over all PCs. The genetic distance among genotypes ranged from 0.10 to 0.37 with an average of 0.24. Cluster analysis using the neighbor-joining (NJ) method suggested there are close relationships between ornamental and some wild genotypes. Although AMOVA results revealed significant differences in the genetic diversity among the regions (P?=?0.0048), the genetic variation was mainly caused by variation of intra regions. The results indicated low genetic differentiation (Fst?=?0.025) and high gene flow (Nm?=?2.28) among regions. These results confirmed that SRAP markers could be powerful tools and an effective marker system for determining the genetic diversity and population genetic structure of the pomegranate.  相似文献   

13.
Senna obtusifolia L. is an important medicinal plant in Asia. This study was the first report on the genetic diversity and population structure of S. obtusifolia which were collected from 47 geographic populations widespread in China. Inter-Simple Sequence Repeat (ISSR) and Start Codon Target Polymorphism (SCoT) combined with seeds morphological traits were used to investigate the relationship of 47 populations. 11 ISSR primers yielded 98 polymorphic bands with 81.67% polymorphism. 24 SCoT primers yielded 267 polymorphic bands with 89.59% polymorphism. The number of allele (Na), the number of effective allele (Ne), Nei’s diversity index (H), and Shannon’s information index (I) reflected a high level of genetic diversity of S. obtusifolia species. The greatest genetic distance (G D) existed between Southwest and Northwest (0.4022ISSR/0.5019SCoT), while the Eastern and Northern showed the least genetic distance (0.1751ISSR/0.2186SCoT). The genetic differentiation (Gst) was 0.4875ISSR/0.4434SCoT, and the gene flow (Nm) was 0.5256ISSR/0.6275SCoT, which indicated that gene exchange among four regions was limited. 47 samples were divided into four clusters mainly according to their geographic distribution through clustering and structure analysis. The analysis on the combined data of ISSR and SCoT showed more reliable and superior results than single analysis of ISSR and SCoT. This study explored the effectiveness of ISSR and SCoT markers to evaluate the genetic diversity and population structure of S. obtusifolia and provided useful information for S. obtusifolia germplasm research and breeding program.  相似文献   

14.
To assess the genetic diversity and the genetic structure of Turkish wild barley (Hordeum spontaneum Tell.) populations, 76 genotypes from ten ecologically and geographically different locations were analyzed by means of amplified fragment length polymorphism (AFLP) markers. Five primer combinations produced 187 scorable bands, of which 117 (62.6%) were polymorphic. Several population-specific and genotype-specific bands were identified, which differentiate populations or genotypes. Genetic distance, determined by Nei’s distance coefficient, varied from 0.07 to 0.21 with an average of 0.13. In the UPGMA dendrogram based on Nei genetic distances, the Hordeum spontaneum populations were separated into two major clusters. Genetic diversity was larger among (68%) than within (32%) populations. Eight AFLP bands were strongly correlated to the altitude of the collecting site, while no clear trend was detected between geographical origin and genetic diversity. Our results strongly suggest the need for a change in Hordeum spontaneum sampling strategy: more populations, rather then more individuals within population, should be sampled to appraise and safeguard genetic diversity in the wild barley gene pool.  相似文献   

15.
To augment conventional crop improvement approaches in cultivated sunnhemp (Crotalaria juncea L.) and other under-utilized Crotalaria species, genetic diversity of 94 genotypes from seven Crotalaria species was studied using 20 Start Codon Targeted (SCoT) markers. High allele number (1.32), polymorphism information content (0.37) and resolving power (6.59) established SCoT as a reliable marker system for genetic analysis in Crotalaria. All the species except Crotalaria retusa L. exhibited high number of SCoT amplicons. Analysis of molecular variance revealed significant variability between (24.0%) the species as well as within species (76.0%). A cluster analysis identified distinct groups corresponding to the seven species and also identified sub-groups within the species. The sunnhemp cultivars were distant from the landraces, suggesting the need of population improvement using distantly related genotypes. Species relationship identified Crotalaria pallida Aiton to be a close relative of C. juncea. The results of principal coordinate analysis were comparable to that of cluster analysis, revealing high genetic variability in sunnhemp and other semi-domesticated Crotalaria species. The study further suggests some measure for conservation of genetic resources and genetic improvement of these species based on the results of diversity analysis.  相似文献   

16.
The genetic diversities of 16 Paulownia fortunei populations involving 143 individuals collected from 6 provinces in China were analyzed using amplified fragment length polymorphism (AFLP). A total of 9 primer pairs with 1169 polymorphic loci were screened out, and each pair possessed 132 bands on average. The percentage of polymorphic bands (98.57%), the effective number of alleles (1.2138–1.2726), Nei’s genetic diversity (0.1566–0.1887), and Shannon’s information index (0.2692–0.3117) indicated a plentiful genetic diversity and different among Paulownia fortune populations. The genetic differentiation coefficient between populations was 0.2386, while the gene flow was 1.0954, and the low gene exchange promoted genetic differentiation. Analysis of variance indicated that genetic variation mainly occurred within populations (81.62% of total variation) rather than among populations (18.38%). The 16 populations were divided by unweighted pair-group method with arithmetic means (UPGMA) into 4 groups with obvious regionalism, in which the populations with close geographical locations (latitude) were clustered together.  相似文献   

17.
Investigation of genetic diversity is essential for the selection of parents for crop breeding and conservation of genetic resources. To estimate the genetic variability and population structure in the midst of 45 accessions of sponge gourd brought together from different geographical areas of India, morphological traits and two molecular markers, ISSR and SCoT markers were compared. Principal components analysis of 20 morphological traits showed 72.70% variability and significant positive correlations between fruit traits. All three marker techniques clustered all accessions into two groups with few outgroups. High level of polymorphism was observed among ISSR (74.6%) and SCoT (71.5%) primers. The Bayesian model revealed the hidden grouping and showed admixture type of population. The diversity pattern is influenced by genetic marker used, as different molecular markers have different polymorphism evaluation efficiency. This study can be helpful in amplifying the genetic base and selection of specific traits for breeding. Thus, ISSR and SCoT markers are potential marker for identification in sponge gourd and provide valuable data on its genetic correlation and structure.  相似文献   

18.

Date palm (Phoenix dactylifera) is an important crop plant both from nutritional and economic points of view. The assessment of genetic diversity and population differentiation of date palms are evaluative for its dynamic conservation and sustainable utilization of its genetic diversity. Estimates of genetic diversity based on molecular markers and fruit characteristics were performed in samples of 23 date palms growing in Ahvaz city (Khuzestan province of Iran). Clustering based on fruit morphological features separated the cultivars in different groups. These cultivars differed significantly in morphological features (P =?0.001). Start codon targeted (SCoT) polymorphism markers revealed a good level of genetic variability (10.17 to 45.76%) in these cultivars. Moreover, STRUCTURE analysis revealed the presence of within-population genetic variability. Analysis of molecular variance revealed a significant genetic difference among date palms, while it showed a higher degree of within-cultivar genetic variability compared with that of among-population diversity. Some degree of common shared alleles occurred between date palm cultivars. Gst versus Nm analysis showed that some of the SCoT markers have a high discrimination power and may have a potential local adaptive value. The Mantel test showed a significant association (r =?0.40, P =?0.001) between morphological and genetic distances. Therefore, both morphological and SCoT molecular data can be used in genetic screening of date palms in the available germplasm.

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19.
张安世  骆扬  范定臣  张中海 《广西植物》2017,37(11):1378-1385
采用SCoT标记分析了18个皂荚种质的遗传多样性,并采用UPGMA法对18个皂荚种质进行了聚类分析。在此基础上,通过筛选出的多态性条带构建了18个皂荚种质的SCoT指纹图谱。扩增结果表明:从51个SCoT引物中筛选了15个引物进行PCR扩增,共扩增出226条带,其中多态性条带216条,多态性比率为96.61%。各引物多态性信息含量(PIC)、观测等位基因数(Na)、有效等位基因数(Ne)、Nei’s基因多样性指数(H)和Shannon’s信息指数(I)的平均值分别为0.875 9、1.964 9、1.440 1、0.272 6、0.426 1。18个皂荚种质的遗传相似系数在0.491 4~0.938 1之间,表明供试材料之间具有较丰富的遗传多样性。聚类分析结果表明:在遗传相似系数为0.60处可将18个皂荚种质分为3组,其中野皂荚单独为一组,山皂荚和皂荚-T聚为一组,其它皂荚材料聚为一组。利用3个引物扩增的8个多态性位点构建了18份皂荚种质资源的DNA指纹图谱,可以将其区分并精准鉴定。该研究结果为皂荚种质的鉴定和新品种选育提供了一定的理论依据。  相似文献   

20.
细叶云南松天然种源林遗传多样性的SSR分析   总被引:2,自引:0,他引:2  
利用12对SSR引物对三个不同种源的细叶云南松群体遗传多样性进行研究。结果表明:共检测到13个位点37个等位基因,每个位点平均观察等位基因数(A)为2.85,多态率为100%;平均有效等位基因数(Ne)1.45。各群体内的有效等位基因数平均为1.447,观察杂合度平均为0.341,期望杂合度平均为0.281。三个群体的Nei’s基因多样度指标的变化范围为0.256~0.297,Shannon多样性指数变化范围为0.448~0.484,各群体间的多态性水平差异不大。细叶云南松群体间的基因分化系数(Gst)为0.089,群体间的遗传分化水平较低,大部分变异均存在群体内。细叶云南松群体间的基因流(Nm)在不同位点的变化范围从4.693~122.189,平均为11.17。说明细叶云南松群体间存在比较充分的基因交流。  相似文献   

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