Comparison of RFLP and RAPD markers to estimating genetic relationships within and among cruciferous species

Restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) markers are being used widely for evaluating genetic relationships of crop germplasm. Differences in the properties of these two markers could result in different estimates of genetic relationships among some accessions. Nuclear RFLP markers detected by genomic DNA and cDNA clones and RAPD markers were compared for evaluating genetic relationships among 18 accessions from six cultivated Brassica species and one accession from Raphanus sativus. Based on comparisons of genetic-similarity matrices and cophenetic values, RAPD markers were very similar to RFLP markers for estimating intraspecific genetic relationships; however, the two marker types gave different results for interspecific genetic relationships. The presence of amplified mitochondrial and chloroplast DNA fragments in the RAPD data set did not appear to account for differences in RAPD- and RFLP-based dendrograms. However, hybridization tests of RAPD fragments with similar molecular weights demonstrated that some fragments, scored as identical, were not homologous. In all these cases, the differences occurred at the interspecific level. Our results suggest that RAPD data may be less reliable than RFLP data when estimating genetic relationships of accessions from more than one species.     

Identification and genetic relationships among nine Albizzia species based on morphological and molecular markers

Abstract

Identifying germplasm is an important component for efficient and effective management of plant genetic resources. This investigation was undertaken for the identification and analysis of genetic variation within 9 species of Albizzia through 33 morphological parameters, and 15 Random Amplified Polymorphic DNA (RAPD) and 17 Inter Simple Sequence Repeat (ISSR) primers. The use of selected RAPD and ISSR primers generated a total of 163 and 201 amplified DNA fragments, respectively. High frequencies of polymorphism, 95.05% for RAPD and 96.02% for ISSR, were detected. Statistical approaches were employed to construct genetic relationships by RAPD, ISSR and morphological analysis. Cluster analysis by the unweighted pair-group method (UPGMA) of Nei's similarity generated dendograms with similar topology that gave a better reflection of the diversity and affinities between species. These molecular results were comparable to main morphological characteristics. The correlation matrices generated by RAPD and ISSR markers were highly correlated (r = 0.843 at p = 1.0), thereby indicating congruence between these two marker systems. Both morphometric data and molecular markers have the potential to analyse genetic variation among the nine species of Albizzia, thus providing a major input for management strategy of plant genetic resources.     

两个地区东方田鼠基因组RAPD分析比较研究

目的　从DNA的水平分析比较两个地区东方田鼠的分子遗传特征,探讨以RAPD标记鉴别两个地区的东方田鼠。方法　筛选6条10bp的随机引物对洞庭湖和青铜峡地区的东方田鼠基因组进行了随机扩增多态DNA(RAPD)分析,并对这两个地区的东方田鼠的基因组DNA进行了比较。结果　①两个地区东方田鼠的所有受试个体中共有的片段数为20条,这是两个地区东方田鼠的共性所在;②两个地区东方田鼠各有其特异性扩增片段;③引物S17和S80可作为鉴别两个地区东方田鼠的特异性引物;④不同地区的东方田鼠其不同个体之间的共享度较低,且存在较大差异;两个地区东方田鼠的遗传背景均呈非均一性。结论　运用RAPD方法可以作为鉴别不同地区东方田鼠的基因多态性的标记。     

Characterization of genetic identities and relationships of Brassica oleracea L. via a random amplified polymorphic DNA assay

Summary Effective conservation and the use of plant genetic resources are essential for future agricultural progress. Critical to this conservation effort is the development of genetic markers which not only distinguish individuals and accessions but also reflect the inherent variation and genetic relationships among collection holdings. We have examined the applicability of the random amplified polymorphic DNA (RAPD) assay for quick, cost-effective, and reliable use in addressing these needs in relation to collection organization and management. Twenty-five decamer oligonucleotide primers were screened individually with a test array composed of individuals representing a range of genetic relationships in Brassica oleracea L. (vegetable and forage cole crops). Over 140 reproducible, polymorphic fragments were generated for study. Each individual of the test array exhibited a unique molecular genotype and composites specific for accessions and botanical varieties could be established. An analysis of similarity based on amplified DNA fragments reflected the known genetic relationships among the selected entries. These results demonstrated that RAPD markers can be of great value in gene bank management for purposes of identification, measurement of variation, and establishment of genetic similarity at the intraspecific level.     

大鼠RAPD标记的观察

采用随机扩增多态ＤＮＡ（ＲＡＰＤ）技术,分析ＳＤ和Ｗｉｓｔａｒ二种大鼠的基因多态性,探讨用ＲＡＰＤ标记鉴别二种大鼠及其血标本实验中的认证,结果表明,二种大鼠表现出了各自不同的多态性ＲＡＰＤ标记,作为大鼠的分子标记,可在基因水平区别二种大鼠,故认为是一种大鼠研究的分子依据。     

Phylogenetic Analysis of Different Breeds of Domestic Chickens in Selected Area of Peninsular Malaysia Inferred from Partial Cytochrome b Gene Information and RAPD Markers

The present investigation was carried out in an attempt to study the phylogenetic analysis of different breeds of domestic chickens in Peninsular Malaysia inferred from partial cytochrome b gene information and random amplified polymorphic DNA (RAPD) markers. Phylogenetic analysis using both neighbor-joining (NJ) and maximum parsimony (MP) methods produced three clusters that encompassed Type-I village chickens, the red jungle fowl subspecies and the Japanese Chunky broilers. The phylogenetic analysis also revealed that majority of the Malaysian commercial chickens were randomly assembled with the Type-II village chickens. In RAPD assay, phylogenetic analysis using neighbor-joining produced six clusters that were completely distinguished based on the locality of chickens. High levels of genetic variations were observed among the village chickens, the commercial broilers, and between the commercial broilers and layer chickens. In this study, it was found that Type-I village chickens could be distinguished from the commercial chickens and Type-II village chickens at the position of the 27th nucleotide of the 351 bp cytochrome b gene. This study also revealed that RAPD markers were unable to differentiate the type of chickens, but it showed the effectiveness of RAPD in evaluating the genetic variation and the genetic relationships between chicken lines and populations.     

Rapid estimation of genetic relatedness among heterogeneous populations of alfalfa by random amplification of bulked genomic DNA samples

A procedure which involves the use of RAPD markers, obtained from bulked genomic DNA samples, to estimate genetic relatedness among heterogeneous populations is demonstrated in this study. Bulked samples of genomic DNA from several alfalfa plants per population were used as templates in polymerase chain reactions with different random primers to produce RAPD patterns. The results show that the RAPD patterns can be used to determine genetic distances among heterogeneous populations and cultivars which correspond to their known relatedness. The results also indicate that, by using ten primers with bulked DNA samples from ten individuals, 18–72 populations or cultivars can be distinguished from each other on the basis of at least one unique RAPD marker. We anticipate that DNA bulking and methods for comparing RAPD patterns will be very useful for identifying cultivars, for studying phylogenetic relationships among heterogeneous populations and for selecting parents to maximize heterosis in crosses.     

Application of random amplified polymorphic DNA and inter-simple sequence repeat markers in the genus Crataegus

Hawthorn ( Crataegus spp.) has a long history as an ornamental and a source of medicine. We report the use of random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers to determine genetic relationships in the genus Crataegus . Twenty-eight accessions, including eight species ( Crataegus pinnatifida , Crataegus bretschneideri , Crataegus maximowiczii , Crataegus kansuensis , Crataegus altaica , Crataegus songarica , Crataegus dahurica and Crataegus sanguinea ) and two botanical varieties ( C. pinnatifida var. major and C. maximowiczii var. ninganensis ) were analysed. Twelve RAPD primers reproducibly and strongly amplified 128 fragments of which 116 were polymorphic; similarly, 13 ISSR primers generated 127 products of which 119 were polymorphic. Dendrograms based on unweighted pair group method with arithmetic average analysis were constructed from both the RAPD and the ISSR data. Similarity coefficient based on RAPD and ISSR markers ranged from 0.22 to 0.98 and 0.23 to 0.98, respectively. The range in similarity coefficient indicated that the genus has a high level of genetic diversity. The Mantel test on the similarity matrices produced by RAPD and ISSR markers gave r  = 0.86, showing high correlation between RAPD and ISSR markers in their ability to detect genetic relationships between Crataegus accessions. RAPD and ISSR appear to be reliable methods for the analysis of genetic relationships among hawthorns.     

Analysis of Genetic Diversity in Cicer arietinum L Using Random Amplified Polymorphic DNA Markers

PCR-based random amplified polymorphic DNA (RAPD) markers were employed to assess genetic diversity in 23 chickpea genotypes. Forty of the 100 random primers screened revealed polymorphism among the genotypes. Most of the primers revealed single polymorphic band, and only 14.1 2% of the products were polymorphic. Estimates of genetic similarity based on Jaccard’s coefficient ranged from 0.92 to 0.99, indicating narrow genetic variability among the genotypes based on RAPD markers.The 23 chickpea genotypes formed two major clusters in the dendrogram.The low RAPD polymorphism among chickpea genotypes suggests that more number of polymorphic primers need to be analysed to determine genetic relationships. It was observed that RAPD analysis employing 30 polymorphic primers could provide better estimates of genetic relationships in chickpea.     

Identification of cultivars and validation of genetic relationships in Mangifera indica L. using RAPD markers

Twenty-five accessions of mango were examined for random amplified polymorphic DNA (RAPD) genetic markers with 80 10-mer random primers. Of the 80 primers screened, 33 did not amplify, 19 were monomorphic, and 28 gave reproducible, polymorphic DNA amplification patterns. Eleven primers were selected from the 28 for the study. The number of bands generated was primer- and genotype-dependent, and ranged from 1 to 10. No primer gave unique banding patterns for each of the 25 accessions; however, ten different combinations of 2 primer banding patterns produced unique fingerprints for each accession. A maternal half-sib (MHS) family was included among the 25 accessions to see if genetic relationships could be detected. RAPD data were used to generate simple matching coefficients, which were analyzed phenetically and by means of principal coordinate analysis (PCA). The MHS clustered together in both the phenetic and the PCA while the randomly selected accessions were scattered with no apparent pattern. The uses of RAPD analysis for Mangifera germ plasm classification and clonal identification are discussed.