Assessment of genetic diversity in Calamus thwaitesii BECC. (Arecaceae) using RAPD markers

Calamus thwaitesii Becc. is a potentially useful rattan found in the Western Ghats of India and Sri Lanka. The wild stock of this rattan species is greatly diminished due to overexploitation for the furniture industry and increasingly rare. Genetic diversity was estimated in 80 samples representing eight populations from the Western Ghats and Sri Lanka using Random Amplified Polymorphic DNA (RAPD) markers. RAPDs generated a total of 120 markers with 10 decamer primers, of which 85% were found to be polymorphic. The percentage of polymorphic loci varied from 40.00 to 60.83 and genetic distance between populations ranged from 0.0332 to 0.2777. Among the analysed populations, Goa was found to be genetically superior followed by Achenkovil, Sinharaja and Talakkaveri. Majority of the genetic diversity was distributed within populations (70.79%) and only (29.21%) among populations. Genetic relationships estimated by the unweighted pair-group method with arithmetic averaging (UPGMA) cluster analysis and principal co-ordinate analysis failed to separate Indian and Sri Lankan populations geographically into two distinct groups.     

Genetic diversity in Vicia amoena (Fabaceae) germplasm resource in China using SRAP and ISSR markers

The genetic diversity in 17 germplasms of Vicia amoena L. from north China was analyzed using SRAP and ISSR markers. Three hundred and sixty-eight (94.11%) polymorphic bands (211 and 157 obtained from 20 pairs of SRAP and ISSR primers, respectively) were scored. Although SRAP was more effective than ISSR markers with higher PIC, RP and larger variation range of genetic distance, both the markers were useful for assessing V. amoena genetic diversity. Cluster analysis showed that the 17 germplasms were clustered into 5 groups. The results of principal coordinate analysis supported UPGMA clustering. The germplasms from source areas where the annual average temperature ranged from −1.0 to 5 °C exhibited the highest level of genetic diversity with the highest PPI, I and H. These results have important implications in genome mapping, breeding purposes, and germplasm conservation.     

Genetic diversity analysis of Pinellia ternata based on SRAP and TRAP markers

An assessment of the genetic diversity and variation of Pinellia ternata collected from 43 populations in China was undertaken using SRAP + TRAP markers. A total of 13 SRAP primers in addition to 3 TRAP primer combinations yielded 292 bands in total of which 286 were polymorphic (98.0%), with an average of 16 for each. The PIC value ranged from 0.88 to 0.95, with a mean polymorphic information content (PIC) of 0.92 over all the primers. A cluster analysis was conducted based on the unweighted pair group method with arithmetic average (UPGMA), and a principle coordinate analysis (PCA) was performed relying on Nei's genetic distance, both of which showed similar outcomes in that the results of clustering did not correlate to the geography locations but showed an association with morphology. An analysis of molecular variance (AMOVA) was performed to detect the source of variation; the results indicated that the main variation existed within populations (67.2%), whereas there was still 32.8% differentiation existing among the populations.     

Genetic diversity and phylogenetic relationships among five endemic Pinus taxa (Pinaceae) of China as revealed by SRAP markers

The genetic diversity and phylogenetic relationships among five endemic Pinus taxa of China (Pinus tabulaeformis, P. tabulaeformis var. mukdensis, P. tabulaeformis f. shekanensis, Pinus massoniana and Pinus henryi) were studied by SRAP markers. Using 10 SRAP primer pairs, 247 bands were generated. The percent of polymorphic bands (94.8%), Nei's genetic diversity (0.2134), and Shannon's information index (0.3426) revealed a high level of genetic diversity at the genus-level. At the taxon level, P. tabulaeformis f. shekanensis and P. henryi showed a higher genetic diversity than the others. The coefficient of genetic differentiation among taxa (0.3332) indicated a higher level of genetic diversity within taxon, rather than among taxa. An estimate of gene flow among taxa was 1.0004 and implied a certain amount of gene exchange among taxa. The results of neighbor-joining cluster analysis and principal co-ordinate analysis revealed that P. tabulaeformis, P. tabulaeformis var. mukdensis and P. tabulaeformis f. shekanensis were conspecific, which was in agreement with the traditional classification. Phylogenetic relationships analysis also indicated that P. henryi might be a distinct species closely related to P. tabulaeformis.     

Determination of genetic diversity among Saccharina germplasm using ISSR and RAPD markers

Various species of genus Saccharina are economically important brown macroalgae cultivated in China. The genetic background of the conserved Saccharina germplasm was not clear. In this report, DNA-based molecular markers such as inter simple sequence repeats (ISSR) and random amplified polymorphic DNA (RAPD) were used to assess the genetic diversity and phylogenetic relationships among 48 Saccharina germplasms. A total of 50 ISSR and 50 RAPD primers were tested, of which only 33 polymorphic primers (17 ISSR and 16 RAPD) had an amplified clear and reproducible profile, and could be used. Seventeen ISSR primers yielded a total of 262 bands, of which 256 were polymorphic, and 15.06 polymorphic bands per primer were amplified from 48 kelp gametophytes. Sixteen RAPD primers produced 355 bands, of which 352 were polymorphic, and 22 polymorphic bands per primer were observed across 48 individuals. The simple matching coefficient of ISSR, RAPD and pooled ISSR and RAPD dendrograms ranged from 0.568 to 0.885, 0.670 to 0.873, and 0.667 to 0.862, revealing high genetic diversity. Based on the unweighted pair group method with the arithmetic averaging algorithm (UPGMA) cluster analysis and the principal components analysis (PCA) of ISSR data, the 48 gametophytes were divided into three main groups. The Mantel test revealed a similar polymorphism distribution pattern between ISSR and RAPD markers, the correlation coefficient r was 0.62, and the results indicated that both ISSR and RAPD markers were effective to assess the selected gametophytes, while matrix correlation of the ISSR marker system (r = 0.78) was better than that of the RAPD marker system (r = 0.64). Genetic analysis data from this study were helpful in understanding the genetic relationships among the selected 17 kelp varieties (or lines) and provided guidance for molecular-assisted selection for parental gametophytes of hybrid kelp breeding.     

Genetic diversity of <Emphasis Type="Italic">Macrophomina phaseolina</Emphasis> isolates from certain agro-climatic regions of India by using RAPD markers

Genetic diversity analysis of Macrophomina phaseolina isolates obtained from different host range and diverse geographical locations in India was carried out using RAPD fingerprinting. Of the thirteen 10-mer random primers used, primer OPB-08 gave the maximum polymorphism and the UPGMA clustering could separate 50 isolates in to ten groups at more than 65% similarity level. The ten clusters correlated well with the geographical locations with exceptions for isolates obtained from Eastern and Western Ghats. There was a segregation of isolates from these two geographical locations in to two clusters thus, distributing 10 genotypes in to eight geographical locations. All the isolates M. phaseolina irrespective of their host and geographical origin, exhibited two representative monomorphic bands at 250 bp and 1 kb, presence of these bands suggests that isolates might have evolved from a common ancestor but due to geographical isolation fallowed by natural selection and genetic drift might have segregated in to subpopulations. Genetic similarity in the pathogenic population reflects the dispersal of single lineage in all locations in India.     

Genetic diversity analysis of Zingiber Officinale Roscoe by RAPD collected from subcontinent of India

The present investigation was undertaken for the assessment of 12 accessions of Zingiber officinale Rosc. collected from subcontinent of India by RAPD markers. DNA was isolated using CTAB method. Thirteen out of twenty primers screened were informative and produced 275 amplification products, among which 261 products (94.90%) were found to be polymorphic. The percentage polymorphism of all 12 accessions ranged from 88.23% to 100%. Most of the RAPD markers studied showed different levels of genetic polymorphism. The data of 275 RAPD bands were used to generate Jaccard’s similarity coefficients and to construct a dendrogram by means of UPGMA. Results showed that ginger undergoes genetic variation due to a wide range of ecological conditions. This investigation was an understanding of genetic variation within the accessions. It will also provide an important input into determining resourceful management strategies and help to breeders for ginger improvement program.     

基于SRAP分子标记的海南沼虾种群遗传多样性

为了调查我国海南沼虾(Macrobrachium hainanense)不同地理种群遗传多样性及遗传分化状况,本文采用序列相关扩增多态性(sequence-related amplified polymorphism,SRAP)标记对我国南方瓯江(OJ)、闽江(MJ)、珠江(PR)、万泉河(WQ)、昌化江(CH)等5个海南沼虾种群的遗传多样性进行了研究。共得到255个清晰、稳定的位点,平均多态位点比例为47.05%,由小到大依次为:PR(43.92%)=WQ(43.92%)相似文献   

Genetic diversity and population structure of Butea monosperma (Lam.) Taub.- a potential medicinal legume tree

Three molecular marker systems, Random Amplified Polymorphic DNA (RAPD), Inter-Simple Sequence Repeats (ISSR) and Sequence-Related Amplified Polymorphism (SRAP) were employed to investigate the genetic structure and diversity among the 14 natural populations of Butea monosperma collected from different geographical regions of India. Detected by 17 RAPD, 15 ISSR and 11 SRAP primer combinations, the proportions of polymorphic bands were 84.2 %, 77.2 % and 91.9 %, respectively, and the mean Nei’s genetic distances among the populations were 0.13, 0.10 and 0.13, respectively. Partitioning of genetic variability by Analysis of molecular variance (AMOVA) revealed that the high genetic diversity was distributed within the populations. AMOVA also revealed that the coefficient of gene differentiation among populations based on F_ST was very high irrespective of markers used. The overall gene flow among populations (Nm) was very low. Cophenetic correlation coefficients of Nei’s distance values and clustering pattern by Mental test were statistically significant for all three marker systems used but poor fit for ISSR data than for RAPD, SRAP and combined data set of all three markers. For all markers, a high similarity in dendrogram topologies was obtained, although some differences were observed with ISSR. The dendrogram obtained by RAPD, SRAP and combined data set of all three markers reflect relationship of most of the populations according to their geographic distribution.     

Genetic diversity analysis among and within populations of Pogostemon cablin from China with ISSR and SRAP markers

The diversity and genetic relationship among and within 16 populations of Pogostemon cablin from China were analyzed using ISSR and SRAP markers. High percentage of polymorphism observed by these two markers indicated a high level of genetic diversity existed among P. cablin populations. The percentage of polymorphic bands revealed by these two markers showed genetic variations were much higher between populations of P. cablin than within. The UPGMA clustering results using ISSR, SRAP or ISSR + SRAP combination showed most accessions from the same or adjacent regions were classified together. However, cluster results based on the absolute contents of patchouli alcohol and pogostone did not keep in good accordance with their geographic distributions, which revealed that the forming of patchouli alcohol and pogostone were relevant to the cultivation conditions except for genetic factors and environmental conditions. Finally, an appropriate strategy for conserving the patchouli germplasm was proposed.     

Genetic diversity analysis of Perinereis aibuhitensis based on ISSR and SRAP markers of Chinese coast populations

The objective of this study was to obtain an overview of the genetic relationships within Perinereis aibuhitensis using Inter-Simple Sequence Repeat (ISSR) and Sequence-Related Amplified Polymorphism (SRAP) markers that were derived from related populations residing in the Chinese coasts. The percentage of polymorphic bands, Nei's gene diversity and Shannon's information index revealed a high level of genetic diversity at the species level. The analysis of molecular variance revealed that 81.22% (ISSR) and 76.29% (SRAP) of variability were partitioned among individuals within populations, which indicated the coherent trend by Nei's genetic differentiation (Gst) (0.2568/0.2876). The gene flow number (Nm) was 1.4470/1.2385, which indicated that there was limited gene exchange between populations. The phylogenetic tree of the ten P. aibuhitensis populations was separated into four major clusters using the neighbor-joining (NJ) method. These results provide a simple and useful basis for P. aibuhitensis germplasm research and aquaculture breeding.     

油莎豆SRAP指纹图谱构建及遗传多样性分析

利用SRAP分子标记构建了14份不同地理来源、表型具有差异的油莎豆品系的分子指纹图谱并进行遗传多样性分析。结果表明100对引物中共有多态性引物42对,扩增出多态性带328条,平均每对引物7.8条。28对引物在12个品系上具有特征谱带,除品系4和14外,均可用1对引物进行鉴定;采用引物组合法仅用Me2/Em6和Me8/Em11这2对引物就可将14份材料区分开,并利用这2对引物构建了上述品系的数字指纹图谱。UPGMA聚类分析表明,所有参试材料间的遗传距离在0.12～0.75之间,平均为0.42,表明我国不同地理来源的油莎豆品系遗传差异较大,具有较为丰富的遗传多样性。     

Genetic diversity and relationships among Canavalia ensiformis (L.) DC. Accessions as revealed by sequence-related amplified polymorphism markers

Canavalia ensiformis is an under-exploited legume that has been used as forage, green manure, and a cover crop. Thus far, studies of the C. ensiformis germplasm have focused on morphological traits, which cannot be used to distinguish all known accessions or to evaluate their genetic diversity precisely. In this study, sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity and relationships among 29 C. ensiformis accessions originating from 16 countries. In total, 274 clear bands were amplified and 144 of them (52.6%) were polymorphic. The polymorphism information content values (PIC) ranged from 0.10 to 0.43, with an average of 0.27. An analysis of molecular variance (AMOVA) revealed that the most significant variation (92.0% of the total) occurred among accessions; the remaining 8.0% was attributed to variation within accessions. A cluster analysis and principal coordinates (PCoA) analysis produced similar results, whereby the 29 C. ensiformis accessions were divided into 5 clusters, each of which was composed of different accessions with different phenotypic traits. This study provides the theoretical basis for future biodiversity studies and breeding programs.     

A comparative analysis of genetic diversity in medicinal Chrysanthemum morifolium based on morphology, ISSR and SRAP markers

The diversity and genetic relationship among 29 populations of Chrysanthemum morifolium, one of Chrysanthemum indicum and one of Chrysanthemum nankingense from China were analyzed using morphological traits and molecular markers. Twenty morphological traits were scored as well as 182 ISSR marker-fragments, as amplified by 22 primers [the percentage of polymorphic bands (PPB): 81.87%], and 243 SRAP marker-fragments as generated by 26 primer pairs (PPB: 75.72%). Mantel’s test indicated significant correlation (r = 0.624) of morphological trait and SRAP. By contrast, the morphological trait showed low correlation with ISSR (r = 0.246). Cluster analysis showed groupings of the accessions according to all four methods correlated well with their geographic region of origin, and most populations from the south of China were classified into one cluster and most populations from the north of China were classified into another cluster. Finally, an appropriate strategy for conserving the C. morifolium germplasm was proposed.     

Genetic diversity in European and Mediterranean faba bean germ plasm revealed by RAPD markers

Broadening of the genetic base and systematic exploitation of heterosis in faba bean requires reliable information on the genetic diversity in the germ plasm. Three groups of faba bean inbred lines were examined by means of RAPDs (random amplified polymorphic DNAs) assays: 13 European small-seeded lines, 6 European large-seeded lines, and 9 Mediterranean lines. Out of 59 primers, 35 were informative and yielded 365 bands, 289 of which were polymorphic with a mean of 8.3 bands per primer. Monomorphic bands were omitted from the analyses and genetic distances (GD) were estimated via the coefficient of Jaccard. The mean GD among the European small-seeded lines was significantly greater than those among the lines of the other two groups. Repeatability of GD estimates was high. Cluster (UPGMA) and principal coordinate analyses identified European small-seeded lines and Mediterranean lines as distinct groups with European large-seeded lines located in between. The results are in harmony with published archaeobotanical findings. We conclude that RAPDs are useful for classification of germ plasm and identification of divergent heterotic groups in faba bean.     

The extent of clonality and genetic diversity in the rare Caldesia grandis (Alismataceae): Comparative results for RAPD and ISSR markers

Genetic variation and clonal diversity of three natural populations of the rare, highly clonal marsh herb Caldesia grandis Samuelsson were investigated using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. Both of the markers worked effectively in clone identification of C. grandis. RAPD markers detected more diversity than ISSR markers in the three populations examined. Of the 60 RAPD primers screened, seven produced highly reproducible bands. Using these primers, a total of 61 DNA fragments were generated with 52 (85.25%) being polymorphic indicating considerable genetic variation at the species level. Analysis of molecular variance (AMOVA) showed that a large proportion of genetic variation (81.5%) resided within populations, while only a small proportion (18.5%) resided among populations. With the use of 52 polymorphic RAPD markers, we were able to identify 127 genets among 342 samples from three populations. The proportion of distinguishable genets (PD: mean 0.37), Simpson's diversity index (D: mean 0.91), and evenness (E: mean 0.78) exhibited high levels of clonal diversity compared to other clonal plants. These results imply that sexual reproduction has played an important role at some time during the history of these populations. Nevertheless, the high level of diversity could have been also partially generated from somatic mutations, although this is unlikely to account for the high diversity generally found among C. grandis genets.     

高大山羊草(Aegilops longissima Schweinf.and Muschl.)遗传多样性的RAPD分析

通过70个 RAPD 引物对高大山羊草15份材料进行扩增,共扩增出766条带,其中无多态性(即相同带)的带115条,占总带数的15%,有多态性的带651条,占总带数的85%。通过分析,发现高大山羊草的 Y315、Y316、Y317与其它12份材料差异很大,这3份材料的特异带有253条,占整个多态性带数的38.9%。经 NTSYS 系统聚类表明,高大山羊草 Y315、Y316、Y317这3份材料为一个类群,而其余12份材料为另一类群;这2个类群中任何一份山羊草与另一类群中任何一份山羊草的遗传距离均很大,变幅为1.38～1.58,是它们各自类群内遗传距离的3倍以上。鉴于这两类材料在分子水平的 RAPD 扩增产物上差异很大,并考虑到这两个类群在形态上也确实存在明显差异,因而建议将高大山羊草分为两个亚种,当然这一观点还有待收集更多的材料做进一步的研究。     

Genetic diversity assessment of a germplasm collection of Salvia miltiorrhiza Bunge. based on morphology,ISSR and SRAP markers

Salvia miltiorrhiza is one of the most important traditional Chinese medicinal plants for its therapeutic effects. In the present study, morphological traits, ISSR (inter-simple sequence related) and SRAP (sequence-related amplified polymorphism) markers were used to analyze the genetic diversity of 59 S. miltiorrhiza phenotypes. Out of the 100 ISSR primers and 100 SRAP primer combinations screened, 13 ISSRs and 7 SRAPs were exploited to evaluate the level of polymorphism and discriminating capacity. The results showed that the 13 ISSRs generated 190 repeatable amplified bands, of which 177 (93.2%) were polymorphic, with an average of 13.6 polymorphic fragments per primer. The 7 SRAPs produced 286 repeatable amplified bands, of which 266 (93.4%) were polymorphic, with an average of 38.1 polymorphic fragments per primer. Cluster analysis readily separated different morphological accessions, wild and cultivated controls based on morphological traits, ISSR and SRAP markers. The study indicated that morphological traits, ISSR and SRAP markers were reliable and effective for assessing the genetic diversity of phenotypic S. miltiorrhiza accessions. The overall results suggested that the introduction of genetic variation from morphology-based germplasms enlarged the genetic base for the collection, conservation and further breeding program of S. miltiorrhiza germplasm.     

Evaluation of genetic relationships in Dalbergia species using RAPD markers

Conservation of identified germplasm is an important component forefficient and effective management of plant genetic resources. Traditionally,species identification has relied on morphological characters like growth habit,floral morphology like flower colour, and agronomic characteristics of the plant.Dalbergia species are important wind-dispersed tropicaltimber trees which exhibit high intrafruit seed abortion because of intensesibling competition for maternal resources. Studies were undertaken foridentification and genetic relationships in five species ofDalbergia and to evaluate genetic diversity withinpopulations of Dalbergia sisso, D.latifolia, D. paniculata, D.assamica and D. spinosa by using randomamplified polymorphic DNAs (RAPD) markers. Analysis was started by using 30decamer primers that allowed to distinguish five species and to select a reducedset of primers. The selected primers were used for identification and forestablishing a profiling system to estimate genetic relationships and toevaluate the genetic variability among the individuals in a population ofDalbergia species. A total of 120 distinct DNA fragments(bands), ranging from 0.3 to 4.0 kb, were amplified byusing nine selected random decamer primers. The genetic similarity was evaluated onthe basis of presence or absence of bands, which revealed a wide range ofvariability within the species. The cluster analysis indicated that five speciesof Dalbergia formed two major clusters. The first clusterconsisted of D. spinosa, D. latifolia and D.sisso. The second cluster was represented by two species, i.e.D. paniculata and D. assamica.A maximum similarity of 60% was observed in D. paniculata andD. assamica and they formed a minor cluster.Dalbergia latifolia and D. sissoformed another minor cluster with more than 50% similarity. Dalbergiaspinosa shared up to 40% similarity with D.latifolia and D. sisso. All the species sharemore than 20% similarity among themselves. The closest genetic distance existedwithin populations of different Dalbergia species. Thus,these RAPD markers have the potential for conservation of identified clones andcharacterization of genetic relatedness among the species. This is also helpful intree breeding programs and provides an important input into conservation biology.     

Assessment of genetic diversity in Brazilian barley using SSR markers

Barley is a major cereal grown widely and used in several food products, beverage production and animal fodder. Genetic diversity is a key component in breeding programs. We have analyzed the genetic diversity of barley accessions using microsatellite markers. The accessions were composed of wild and domesticated barley representing genotypes from six countries and three breeding programs in Brazil. A total of 280 alleles were detected, 36 unique to Brazilian barley. The marker Bmag120 showed the greatest polymorphism information content (PIC), with the highest mean value found on chromosome three, and the lowest on chromosomes four and six. The wild accessions presented the highest diversity followed by the foreign genotypes. Genetic analysis was performed using Principal Coordinates Analysis, UPGMA clustering, and Bayesian clustering analysis implemented in Structure. All results obtained by the different methods were similar. Loss of genetic diversity has occurred in Brazilian genotypes. The number of alleles detected in genotypes released in 1980s was higher, whereas most of the cultivars released thereafter showed lower PIC and clustered in separate subgroups from the older cultivars. The use of a more diverse panel of genotypes should be considered in order to exploit novel alleles in Brazilian barley breeding programs.