Qualitative and quantitative characterization of RAPD variation among snap bean (Phaseolus vulgaris) genotypes

Ten snap bean (Phaseolus vulgaris) genotypes were screened for polymorphism with 400 RAPD (random amplified polymorphic DNA) primers. Polymorphic RAPDs were scored and classified into three categories based on ethidium bromide staining intensity. An average of 5.19 RAPD bands were scored per primer for the 364 primers that gave scorable amplification products. An average of 2.15 polymorphic RAPDs were detected per primer. The results show that primer screening may reduce the number of RAPD reactions required for the analysis of genetic relationships among snap-bean genotypes by over 60%. Based on the analysis of the distribution of RAPD amplification, the same number of polymorphic RAPDs were amplified from different genotypes for all RAPD band intensity levels. A comparison of RAPD band amplification frequency among genotypes for the three categories of bands classified by amplification strength revealed a measurable difference in the frequencies of RAPDs classified as faint (weakly amplifying) compared to RAPD bands classified as bold (strongly amplifying) indicating a possible scoring error due to the underscoring of faint bands. Correlation analysis showed that RAPD bands amplified by the same primer are not more closely correlated then RAPD bands amplified by different primers but are more highly correlated then expected by chance. Pairwise comparisons of RAPD bands indicate that the distribution of RAPD amplification among genotypes will be a useful criterion for establishing RAPD band identity. For the average pairwise comparison of genotypes, 50% of primers tested and 15.8% of all scored RAPDs detected polymorphism. Based on RAPD data Nei's average gene diversity at a locus was 0.158 based on all scorable RAPD bands and 0.388 if only polymorphic RAPD loci were considered. RAPD-derived 1 relationships among genotypes are reported for the ten genotypes included in this study. The data presented here demonstrate that many informative, polymorphic RAPDs can be found among snap bean cultivars. These RAPDs may be useful for the unique identification of bean varieties, the organization of bean germplasm, and applications of molecular markers to bean breeding.     

Comparison of RAPD and RFLP genetic markers in determining genetic similarity among Brassica oleracea L. genotypes

Genetic similarity among 45 Brassica Oleracea genotypes was compared using two molecular markers, random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphisms (RFLPs). The genotypes included 37 broccolis (var. italica), five cauliflowers (var. botrytis) and three cabbages (var. capitata) which represented a wide range of commercially-available germplasm, and included open-pollinated cultivars, commercial hybrids, and inbred parents of hybrid cultivars. Fifty-six polymorphic RFLP bands and 181 polymorphic RAPD bands were generated using 15 random cDNA probes and 62 10-mer primers, respectively. The objectives were to compare RFLP and RAPD markers with regard to their (1) sampling variance, (2) rank correlations of genetic distance among sub-samples, and (3) inheritance. A bootstrap procedure was used to generate 200 random samples of size n (n=2,3,5,... 55) independently from the RAPD and RFLP data sets. The coefficient of variance (CV) was estimated for each sample. Pooled regressions of the coefficient of variance on bootstrap sample size indicated that the rate of decrease in CV with increasing sample size was the same for RFLPs and RAPDs. The rank correlation between the Nei-Li genetic similarity values for all pairs of genotypes (990) based on RFLP and RAPD data was 0.745. Differences were observed between the RFLP and RAPD dendrograms of the 45 genotypes. Overlap in the distributions of rank correlations between independent sub-samples from the RAPD data set, compared to correlations between RFLP and RAPD sub-samples, suggest that observed differences in estimation of genetic similarity between RAPDs and RFLPs is largely due to sampling error rather than due to DNA-based differences in how RAPDs and RFLPs reveal polymorphisms. A crossing algorithm was used to generate hypothetical banding patterns of hybrids based on the genotypes of the parents. The results of this study indicate that RAPDs provide a level of resolution equivalent to RFLPs for detemination of the genetic relationships among genotypes.     

An evaluation of RAPD fragment reproducibility and nature

Random amplified polymorphic DNA (RAPD) fragment reproducibility was assayed in three animal species: red deer ( Cervus elaphus ), wild boar ( Sus scrofa ) and fruit fly ( Drosophila melanogaster ). Ten 10-mer primers (Operon) were tested in two replicate reactions per individual under different stringency conditions (annealing temperatures of 35 °C or 45 °C). Two estimates were generated from the data: autosimilarity, which tests the reproducibility of overall banding patterns, and band repeatability, which tests the reproducibility of specific bands. Autosimilarity (the similarity of individuals with themselves) was lower than 1 for all three species ranging between values of 0.66 for Drosophila at 45 °C and 0.88 for wild boar at 35 °C. Band repeatability was estimated as the proportion of individuals showing homologous bands in both replicates. The fraction of repeatable bands was 23% for deer, 36% for boar and 26% for fruit fly, all at an annealing temperature of 35 °C. Raising the annealing temperature did not improve repeatability. Phage lambda DNA was subjected to amplification and the pattern of bands compared with theoretical expectations based on nucleotide sequence. Observed fragments could not be related to expected ones, even if a 2bp mismatch is allowed. Therefore, the nature of genetic variation uncovered by the RAPD method is unclear. These data demonstrate that prudence should guide inferences about population structure and nucleotide divergence based on RAPD markers.     

Genetic diversity in Elymus caninus as revealed by isozyme, RAPD, and microsatellite markers.

Genetic diversity of 33 Elymus caninus accessions was investigated using isozyme, RAPD, and microsatellite markers. The three assays differed in the amount of polymorphism detected. Microsatellites detected the highest polymorphism. Six microsatellite primer pairs generated a total of 74 polymorphic bands (alleles), with an average of 15.7 bands per primer pair. Three genetic similarity matrices were estimated based on band presence or absence. Genetic diversity trees (dendrograms) were derived from each marker technique, and compared using Mantel's test. The correlation coefficients were 0.204, 0.267, and 0.164 between isozyme and RAPD distance matrices, RAPD and microsatellite distance matrices, and between isozyme and microsatellite distance matrices, respectively. The three methodologies gave differing views of the amount of variation present but all showed a high level of genetic variation in E. caninus. The following points may be drawn from this study whether based on RAPD, microsatellite, or isozyme data: (i) The Icelandic populations are consistently revealed by the three dendrograms. The congruence of the discrimination of this accession group by RAPD, microsatellite, and isozyme markers suggests that geographic isolation strongly influenced the evolution of the populations; (ii) The degree of genetic variation within accessions was notably great; and (iii) The DNA-based markers will be the more useful ones in detecting genetic diversity in closely related accessions. In addition, a dendrogram, which took into account all fragments produced by isozymes, RAPDs, and microsatellites, reflected better the relationships than did dendrograms based on only one type of marker.     

Comparative analysis of genetic relationships in barley based on RFLP and RAPD markers

Genetic relationships have seldom been analyzed with different types of molecular markers in order to compare the information provided by each marker class. We investigated genetic relationships among nine barley cultivars using separate cluster analyses based on restriction fragment length polymorphisms (RFLPs) and random amplified polymorphic DNAs (RAPDs). Genomic DNA restricted with three enzymes and hybridized with 68 probes revealed 415 RFLPs (74.2% of all bands). Among the 128 primers used for RAPD analysis, 100 provided a reproducible profile, 89 of which revealed 202 polymorphic and 561 monomorphic bands (26.5 and 73.5%, respectively). A nonrandom distribution of 62 RAPDs with a tendency to cluster near centromeric regions was produced when these RAPDs were mapped using 76 doubled-haploid lines derived from a cross between two of the nine cultivars. The correlation between the RFLP and RAPD similarity matrices computed for the 36 pairwise comparisons among the nine cultivars was equal to 0.83. The dendrograms obtained by cluster analyses of the RFLP and RAPD data differed. These results indicate that in barley the information provided by RFLPs and RAPDs is not equivalent, most likely as a consequence of the fact that the two marker classes explore, at least in part, different portions of the genome.     

Genetic relationships among melon breeding lines revealed by RAPD markers and agronomic traits

 RAPD markers and agronomic traits were used to determine the genetic relationships among 32 breeding lines of melon belonging to seven varietal types. Most of the breeding lines were Galia and Piel de Sapo genotypes, which are currently being used in breeding programmes to develop new hybrid combinations. A total of 115 polymorphic reliable bands from 43 primers and 24 agronomic traits were scored for genetic distance calculations and cluster analysis. A high concordance between RAPDs and agronomic traits was observed when genetic relationships among lines were assessed. In addition, RAPD data were highly correlated with the pedigree information already known for the lines and revealed the existence of two clusters for each varietal type that comprised the lines sharing similar agronomic features. These groupings were consistent with the development of breeding programmes trying to generate two separate sets of parental lines for hybrid production. Nevertheless, the performance of certain hybrids indicated that RAPDs were more suitable markers than agronomic traits in predicting genetic distance among the breeding lines analysed. The employment of RAPDs as molecular markers both in germplasm management and improvement, as well as in the selection of parental lines for the development of new hybrid combinations, is discussed. Received: 25 July 1997 / Accepted: 6 October 1997     

A comparison of RAPD and isozyme analyses for determining the genetic relationships among Avena sterilis L. accessions

Isozyme analysis is a valuable tool for determining genetic relationships among breeding lines and populations. The recently developed DNA technologies which can assay a greater proportion of the plant genome are providing a plentiful array of additional genomic markers. The objective of this research was to compare random amplified polymorphic DNA (RAPD) versus isozyme-based estimation of relationships among 24 accessions of a hexaploid wild oat, Avena sterilis L. The accessions were evaluated for variation in 23 enzyme systems and by 21 10-mer primers. A total of 77 polymorphic isozyme bands and 115 polymorphic RAPD bands were observed. Two matrices of genetic distances were estimated based on band presence/ absence. These matrices were subsequently utilized in cluster analysis and principal coordinate analysis. Both isozymes and RAPDs were proficient at distinguishing between the 24 accessions. The correspondence between the elements of both distance matrices was moderate (r=0.36**). Nevertheless, the overall representation of relationships among accessions by cluster analysis and ordination was in considerable agreement. The two techniques contrasted most notably in pair-by-pair comparisons of relationships. RAPD analysis resulted in a more definitive separation of clusters of accessions. The most significant impact of the DNA-based markers probably will be the more accurate determination of relationships between accessions that are too close to be accurately differentiated by isozymes.The research reported in this publication was funded by the North Carolina Agricultural Research Service, the North Carolina Biotechnology Center, and by a Heisenberg Fellowship (HE 1497/3-2) provided by the German Research Council to Manfred Heun     

Estimation of genetic distance based on RAPDs between 11 cotton accessions varying in heat tolerance

The genetic distance of 11 cotton genotypes varying in heat tolerance was studied using RAPD markers. Fifty-three random decamer primers were used for the estimation of genetic distance. Among the 53 RAPD primers, which were custom synthesized by GeneLink Inc., UK, 32 were polymorphic and 21 were monomorphic. The 32 polymorphic primers produced 273 fragments, with a mean of 8.3 fragments per primer. The number of polymorphic bands produced in the 11 cotton accessions ranged from 1 to 31. Primer GLC-20 produced 31 polymorphic bands, while two primers, GLB-5 and GLC-12, produced one polymorphic band each. A range of 88.89 to 42.48% genetic similarity was observed among the 11 cotton accessions. The highest genetic similarity was observed between FH-945 and BH-160 (88.89%), whereas the lowest value was found between NIAB-801/2 and FH-945 (42.48%). Unique amplification profiles were produced by most of the cultivars; the differences were sufficient to distinguish them from other genotypes. This confirms the efficacy of RAPD markers for the identification of plant genotypes. An accumulative analysis of amplified products generated by RAPDs was sufficient to assess the genetic diversity among the genotypes. This information should be helpful for formulating breeding and genome mapping programs.     

RAPD polymorphism of wild emmer wheat populations, Triticum dicoccoides, in Israel

 Genetic diversity in random amplified polymorphic DNAs (RAPDs) was studied in 110 genotypes of the tetraploid wild progenitor of wheat, Triticum dicoccoides, from 11 populations sampled in Israel and Turkey. Our results show high level of diversity of RAPD markers in wild wheat populations in Israel. The ten primers used in this study amplified 59 scorable RAPD loci of which 48 (81.4%) were polymorphic and 11 monomorphic. RAPD analysis was found to be highly effective in distinguishing genotypes of T. dicoccoides originating from diverse ecogeographical sites in Israel and Turkey, with 95.5% of the 100 genotypes correctly classified into sites of origin by discriminant analysis based on RAPD genotyping. However, interpopulation genetic distances showed no association with geographic distance between the population sites of origin, negating a simple isolation by distance model. Spatial autocorrelation of RAPD frequencies suggests that migration is not influential. Our present RAPD results are non-random and in agreement with the previously obtained allozyme patterns, although the genetic diversity values obtained with RAPDs are much higher than the allozyme values. Significant correlates of RAPD markers with various climatic and soil factors suggest that, as in the case of allozymes, natural selection causes adaptive RAPD ecogeographical differentiation. The results obtained suggest that RAPD markers are useful for the estimation of genetic diversity in wild material of T. dicoccoides and the identification of suitable parents for the development of mapping populations for the tagging of agronomically important traits derived from T. dicoccoides. Received: 13 July 1998 / Accepted: 13 August 1998     

Assessment of genetic variation withinBrassica campestris cultivars using amplified fragment length polymorphism and random amplification of polymorphic DNA markers

Genetic relationships were evaluated among nine cultivars ofBrassica campestris by employing random amplification of polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers. RAPDs generated a total of 125 bands using 13 decamer primers (an average of 9.6 bands per assay) of which nearly 80% were polymorphic. The per cent polymorphism ranged from 60–100%. AFLP, on the other hand generated a total of 319 markers, an average of 64 bands per assay. Of these, 213 were polymorphic in nature (66.8%). AFLP methodology detected polymorphism more efficiently than RAPD approach due to a greater number of loci assayed per reaction. Cultivar-specific bands were identified, for some cultivars using RAPD, and for most cultivars with AFLP. Genetic similarity matrix, based on Jaccard’s index detected coefficients ranging from 0.42 to 0.73 for RAPD, and from 0.48 to 0.925 for AFLPs indicating a wide genetic base. Cluster analyses using data generated by both RAPD and AFLP markers, clearly separated the yellow seeded, self-compatible cultivars from the brown seeded, self-incompatible cultivars although AFLP markers were able to group the cultivars more accurately. The higher genetic variation detected by AFLP in comparison to RAPD was also reflected in the topography of the phenetic dendrograms obtained. These results have been discussed in light of other studies and the relative efficiency of the marker systems for germplasm evaluation.     

Monitoring of cultivar identity in tissue culture-derived date palms using RAPD and AFLP analysis

In the present study, two polymerase chain reaction (PCR)-based methods namely, randomly amplified polymophic DNA (RAPD) and amplification fragment length polymorphism (AFLP) were employed to assess genetic variations, which may appeared, in tissue culture-derived date palm (Phoenix dactylifera) offshoots. Analysis of RAPD banding patterns generated by PCR amplification using 37 random primers gave no evidences for somaclonal variations and the percentage of polymorphic bands in a total of 259 scored bands was zero. Meanwhile, analysis of AFLP banding patterns generated using 13 primer combinations pointed to minor genetic variations in the AFLP banding patterns. The percentage of genetic variations (polymorphism) in tissue culture-derived date palm offshoots belonging to cultivars Sakkoty, Gandila and Bertamoda was 2.6, 0.79 and 1 %, respectively, as revealed by AFLP analysis. The low percentage of genetic variations confirms the genetic stability of tissue culture-derived dry date palm cultivars.     

Comparison of RAPD and ISSR markers for assessment of genetic diversity among endangered rare Dalbergia oliveri (Fabaceae) genotypes in Vietnam

Dalbergia oliveri is a leguminous tree of the Fabaceae family. This species is popular and valuable in Vietnam and is currently listed on the Vietnam Red List and on the IUCN Red List as endangered. Two PCR techniques using RAPD and inter-simple sequence repeat (ISSR) markers were used to make a comparative analysis of genetic diversity in this species. Fifty-six polymorphic primers (29 RAPD and 27 ISSR) were used. The RAPD primers produced 63 bands across 35 genotypes, of which 24 were polymorphic. The number of amplified bands varied from one to four, with a size range from 250 to 1400 bp. The percentage polymorphism ranged from 0 to 75. Amplification of genomic DNA of the 35 genotypes, using ISSR analysis, yielded 104 fragments, of which 63 were polymorphic. The number of amplified fragments using ISSR primers ranged from one to nine and varied in size from 250 to 1500 bp. The percentage polymorphism ranged from 0 to 100. ISSR markers were relatively more efficient than RAPDs. The mental test between two Jaccard's similarity matrices gave r ≥0.802, showing good fit correlation between ISSRs and RAPDs. Clustering of isolates remained more or less the same for RAPDs compared to combined RAPD and ISSR data. The similarity coefficient ranged from 0.785 to 1.000, 0.698 to 0.956 and 0.752 to 0.964 with RAPD, ISSR, and the combined RAPD-ISSR dendrogram, respectively.     

应用RAPD技术对蜘蛛系统演化的初步研究

利用随机扩增多态ＤＮＡ 技术检测了３ 类不同蜘蛛的系统发生关系．用１２ 个随机引物对各实验蜘蛛的基因组ＤＮＡ 进行扩增,选择其中扩增谱带清晰的８ 个引物进行分析并计算不同类蜘蛛间的遗传距离．结果表明：所有８ 个引物获得的ＲＡＰＤ谱带均表现为不同程度的多态性;地穴型蜘蛛与结网型蜘蛛间的遗传距离及结网型与游猎型之间的遗传距离,均比地穴型与游猎型之间的遗传距离近,体现了蜘蛛由地穴→结网→游猎的系统演化进程．这一结论与根据古生物学、胚胎学、形态学及生态学等得出的结论一致,从而进一步从ＤＮＡ 分子水平上为蜘蛛系统演化提供了新的证据．     

Suitability of RAPD for analyzing spined and spineless variant regenerants of pineapple (Ananas comosus L., Merr.)

A random amplified polymorphic DNA (RAPD) analysis of spineless (variant phenotype) plants obtained from micropropagated dormant pineapple (Ananas comosus L., Merr.) axillary buds was performed using arbitrary 10-mer oligonucleotide primers. This was done to investigate the genetic fidelity of the regenerants and to distinguish these variants from regenerants bearing the normal spined phenotype. Of the 58 arbitrary primers used, 29 produced bands unique to the spineless phenotype, and 30 produced bands unique to the spined phenotype. A total of 914 bands were scored, 55 of which were polymorphic to the spineless phenotype and 51 of which were polymorphic to the spined phenotype. On the basis of RAPD amplification products, genetic similarity was estimated in both types of regenerants using similarity coefficients (Nei and Li, 1979). The characteristic finger-prints generated by each probe emphasize genetic variability of regenerants. This technique is suitable for analyzing variant regenerants induced in vitro.     

Genetic variation within and among populations of a wild rice Oryza granulata from China detected by RAPD and ISSR markers

Genetic variation within and between five populations of Oryza granulata from two regions of China was investigated using RAPD (random amplified polymorphic DNA) and ISSR (inter-simple sequence repeat amplification) markers. Twenty RAPD primers used in this study amplified 199 reproducible bands with 61 (30.65%) polymorphic; and 12 ISSR primers amplified 113 bands with 52 (46.02%) polymorphic. Both RAPD and ISSR analyses revealed a low level of genetic diversity in wild populations of O. granulata. Furthermore, analysis of molecular variance (AMOVA) was used to apportion the variation within and between populations both within and between regions. As the RAPD markers revealed, 73.85% of the total genetic diversity resided between the two regions, whereas only 19.45% and 6.70% were present between populations within regions and within a population respectively. Similarly, it was shown by ISSR markers that a great amount of variation (49.26%) occurred between the two regions, with only 38.07% and 12.66% between populations within regions and within a population respectively. Both the results of a UPGMA cluster, based on Jaccard coefficients, and pairwise distance analysis agree with that of the AMOVA partition. This is the first report of the partitioning of genetic variability within and among populations of O. granulata at the DNA level, which is in general agreement with a recent study on the same species in China using allozyme analysis. Our results also indicated that the percentage of polymorphic bands (PPB) detected by ISSR is higher than that detected by RAPD. It seems that ISSR is superior to RAPD in terms of the polymorphism detected and the amplification reproducibility. Received: 29 March 2000 / Accepted: 15 May 2000     

中国茶树初选核心种质遗传多样性的RAPD分析

以中国茶树初选核心种质中的69份种质为实验材料,采用改良的SDS法提取它们的基因组DNA,并运用优化的RAPD 分析体系对基因组DNA进行分子标记遗传差异研究。从50个随机引物中筛选出32个扩增效果好的引物,对全部试验材料进 行了RAPD扩增共得到348条有效带,其中多态性带为328条(占94.3%),它们之间的遗传距离为0.223～0.723。研究结果表 明中国茶树初选核心种质的遗传结构、遗传多样性和遗传距离基本上能较好的代表中国的茶树种质资源。同时,指出结合形 态标记和DNA分子标记是构建茶树核心种质较好的选择。     

中国食用向日葵种质资源遗传变异的RAPD及AFLP分析

本研究采用RAPD和AFLP方法对23个中国不同地区的食用向日葵（Helianthus annuus L.)骨干品种进行了遗传变异分析,同时对两种标记系统进行了比较。26个RAPD引物产生了总计192条DNA条带,大小分布 于0.26kb-1.98kb之间,其中165条（86．12％）具有多态性,每条引物产生DNA条带的平均数为7．38。8对AFLP引物组合共产生了576条带,分布于100bp-500bp之间,其中的341条具有多态性,多态百分率为76．00％,每对引物组合产生DNA条带的平均数为72。RAPD方法检测的每位点有效等位基因数（1．76）大于AFLP（1．65）,AFLP标记位点的平均多态性信息量（PIC）（0．38）低于RAPD标记位点PIC（0．41）,但AFLP标记具有很高的多态性检测效率（Ai=38．52）。用RAPD标记分析23个食用向日葵材料的亲缘关系,Nei氏相似性系数分布在47．84％－82．06％,平均相似性系数为0．6495,而采用AFLP的Nei氏相似性系数分布在54．15％－83．52％,平均相似性系数为0．6884。RAPD数据的标准差为0．13,而AFLP数据的标准差为0．08。因此,采用RAPD和AFLP方法分析食用向日葵遗传变异,RAPD标记具有较低相似性系数和较高方差而AFLP则相反。源于两种不同标记的遗传相似矩阵的相关系数为0．51,说明采用RAPD和AFLP系统分析食用向日葵遗传变异得到的结果有一定的相关性,无论采用RAPD还是AFLP标记进行聚类分析,都将23个不同基因型的食用向日葵材料分成了三个类群。     

Rapid identification of white-Engelmann spruce species by RAPD markers

Fragments of random amplified polymorphic DNA (RAPDs) were used as markers to distinguish Picea glauca (Moench) Voss (white spruce) and Picea engelmannii Parry (Engelmann spruce). These species and their putative hybrids are difficult to differentiate morphologically and are collectively known as interior spruce. Four oligodeoxynucleotide decamer primers showed species-specific amplification products between white spruce and Engelmann spruce. These fragments are highly conserved among seed lots and individual trees of each species from diverse geographic origins. The consistency and reproducibility of these species-specific amplification products were tested in more than two amplification reactions. Therefore, RAPD markers can provide genetic markers for easy and rapid identification of the specific genetic entry of these spruce species and their reported putative hybrids. According to the frequencies of the species-specific RAPD markers, it is possible to estimate the hybrid fraction, indicative of true introgression between the two species. These results are useful for quick identification of both species and their hybrid swarms at any stage in the sporophyte phase of the life cycle, for determining the occurrence and the magnitude of introgressive hybridization in an overlap zone between the two species, and for certification purposes in operational re-forestation and tree-improvement programs.     

Genetic mapping of mutations using phenotypic pools and mapped RAPD markers.

Genetic markers facilitate the study of inheritance and the cloning of genes by genetic approaches. Molecular markers detect differences in DNA sequence, and are thus less ambiguous than phenotypic markers, which require gene expression. We have demonstrated a molecular approach to the mapping of mutant genes using RAPD markers and pooling of individuals based on phenotype. To map genes by phenotypic pooling a strain carrying a mutation is crossed to a strain that is homozygous for the wild-type allele of the corresponding gene. A set of primers corresponding to mapped RAPDs distributed throughout the genome and in coupling phase with respect to the wild type parent is then used to amplify DNA from wild type and mutant pools of F2 individuals. Linkage between the mutant gene and the RAPD markers is visualized by the absence of the corresponding RAPD DNA bands in the mutant pool. We developed a mathematical model for calculating the probability of linkage between RAPDs and target genes and we successfully tested this approach with the model plant Arabidopsis thaliana.     

Lack of genetic variation of an invasive clonal plant Eichhornia crassipes in China revealed by RAPD and ISSR markers

Random amplified polymorphic DNAs (RAPDs) and inter-simple sequence repeats (ISSRs) markers were used to analyze genetic structure of six populations of invasive plant Eichhornia crassipes that were sampled from its introduced regions in Southern China. Using 25 RAPD primers and 18 ISSR primers, 172 RAPD bands and 145 ISSR bands were produced respectively. But no polymorphic band was detected either within population or among populations by both markers, indicating the genetic diversity of E. crassipes in Southern China is extremely low, and all populations most likely consist of the same genotype. This study suggested that some other adaptability related factors, other than the genetic diversity, are responsible to the E. crassipes rapid expansion in China.