Taxonomic relationships in East AsianVicia species with unijugate leaves based on random amplified polymorphic DNA markers

Random amplified polymorphic DNA(RAPD) markers were investigated to clarify the taxonomic positions ofVicia linearifolia andV. bifolia, and to assess the genomic diversity among the 9 populations ofV. unijuga, each of which represents a geographical variation or infraspecific taxa in southern Korea. These species are characterized by unijugate leaves in East Asia and have been controversial as to infra-or interspecific classification. The polymorphic markers among the populations examined were observed for fifteen decamer primers. The degree of band sharing was used to calculate genetic similarity between populations, and a phenogram using UPGMA cluster analysis was generated based on the Dice similarity coefficient. The taxa studied were divided into two main groups and the populations ofV. unijuga were all grouped together in the phenogram. The genetic similarities ofV. unijuga were very high among the populations and did not show distinctions between the infraspecific taxa, although the populations of Mt. Odae and adjacent areas in eastern Korea were different from others of the species.V. linearifolia fell within the range of the genomic variation among the populations ofV. unijuga, whileV. bifolia was grouped withV. venosa var.cuspidata having multijugate leaves rather thanV. unijuga. The result from studying RAPD markers suggested thatV. linearifolia should be integrated intoV. unijuga and that species with unijugate leaves ofV. bifolia andV. unijuga are polyphyletic.     

Expression of recombinant alpha and beta tubulins from the yew Taxus cuspidata and analysis of the microtubule assembly in the presence of taxol

Taxol was originally isolated from the yew Taxus brevifolia. Because taxol inhibits the depolymerization of microtubules, the presence of a self-resistance mechanism in Taxus spp. was hypothesized. The cloning of the cDNA for alpha and beta tubulins from Taxus cuspidata and those from the human embryonic kidney cell line HEK293T revealed that the ²⁶Asp, ³⁵⁹Arg, and ³⁶¹Leu residues in the human beta tubulin, which are important for taxol binding, were replaced with Glu, Trp, and Met in the beta tubulin of T. cuspidata, respectively. The microtubule assembly of the recombinant alpha and beta tubulins was monitored turbidimetrically, and the results clearly demonstrated that the microtubule from T. cuspidata is less sensitive to taxol than that from HEK293T cells. The Taxus microtubule composed of the wild-type alpha tubulin and the beta tubulin with the E26D mutation restored the sensitivity to taxol. We thus postulated that the mutation identified in the beta tubulin of T. cuspidata plays a role in the self-resistance of this species against taxol.     

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     

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     

Genetic diversity in North American ginseng (Panax quinquefolius L.) grown in Ontario detected by RAPD analysis

Genetic diversity within North American ginseng (Panax quinquefolius L.) grown in Ontario was investigated at the DNA level using the randomly amplified polymorphic DNA (RAPD) method via the polymerase chain reaction (PCR). A total of 420 random decamers were initially screened against DNA from four ginseng plants and 78.8% of them generated RAPD fragments. Thirty-six of the decamers that generated highly repeatable polymorphic RAPD markers were selected for further RAPD analysis of the ginseng population. With these primers, 352 discernible DNA fragments were produced from DNA of 48 ginseng plants, corresponding to an average of 9.8 fragments per primer, of which over 45% were polymorphic. The similarity coefficients among the DNA of ginseng plants analyzed were low, ranging from 0.149 to 0.605 with a mean of 0.412, indicating that a high degree of genetic diversity exists in the ginseng population. Lower levels of genetic diversity were detected among 3-year-old ginseng plants selected on the basis of greater plant height than among the plants randomly selected from the same subpopulation or over the whole population, suggesting that genetic factors at least partly contribute to morphological variation within the ginseng population and that visual selection can be effective in identifying the genetic differences. The significance of a high degree of genetic variation in the ginseng population on its potential for improvement by breeding is also discussed.     

Using RAPD markers to identify genets of an arable grass weed, Arrhenatherum elatius ssp. bulbosum

RAPD (Random Amplified Polymorphic DNA) markers were used to identify genets within a weed infestation of Arrhenatherum elatius ssp bulbosum (“onion couch”). Three selected primers could discriminate between 18 sexually-derived plants of A. elatius ssp. elatius. Using these primers, RAPD phenotypes were obtained for ramets of ssp. bulbosum from a population of unknown sexual derivation, i.e. predominantly sexual or vegetative. Thirty three RAPD phenotypes were observed amongst 65 plants. Ramets with identical RAPD phenotypes were termed “genets”. Some genets of ssp. bulbosum were found in localised patches, whereas others had much wider ranges, indicating long-distance dispersal by farm machinery. RAPD markers provide a useful tool for discriminating between genets within an established plant population.     

Genetic variation,population structure and identification of yellow catfish, <Emphasis Type="Italic">Mystus nemurus</Emphasis> (C&;V) in Thailand using RAPD,ISSR and SCAR marker

Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers were used to investigate the genetic structure of four subpopulations of Mystus nemurus in Thailand. The 7 RAPD and 7 ISSR primers were selected. Of 83 total RAPD fragments, 80 (96.39%) were polymorphic loci, and of 81 total ISSR fragments, 75 (92.59%) were polymorphic loci. Genetic variation and genetic differentiation obtained from RAPD fragments or ISSR fragments showed similar results. Percentage of polymorphic loci (%P), observed number of alleles, effective number of alleles, Nei’s gene diversity (H) and Shannon’s information index revealed moderate to high level of genetic variations within each M. nemurus subpopulation and overall population. High levels of genetic differentiations were received from pairwise unbiased genetic distance (D) and coefficient of differentiation. Mantel test between D or gene flow and geographical distance showed a low to moderate correlation. Analysis of molecular variance indicated that variations among subpopulations were higher than those within subpopulations. The UPGMA dendrograms, based on RAPD and ISSR, showing the genetic relationship among subpopulations are grouped into three clusters; Songkhla (SK) subpopulation was separated from the other subpopulations. The candidate species-specific and subpopulation-specific RAPD fragments were sequenced and used to design sequence-characterized amplified region primers which distinguished M. nemurus from other species and divided SK subpopulation from the other subpopulations. The markers used in this study should be useful for breeding programs and future aquacultural development of this species in Thailand.     

南方红豆杉不同居群遗传多样性的RAPD研究

用随机扩增多态性方法对广东、湖南、江西等3省的12个南方红豆杉自然居群进行了基因组DNA多态性分析,从100条引物中共筛选出10个引物,获得RAPD谱带86条,多态性谱带占51％。聚类分析结果表明：南方红豆杉居群间的遗传距离与这些居群的地理分布相关,即相同或相邻产地的居群间的遗传距离较小,不同产地个体间的遗传距离较大。粤北南方红豆杉的9个居群的遗传多样性较低,可能与近年来资源遭到严重破坏,及其生长缓慢、种子萌发率低、成活率不高等原因有关。     

Deletion of a large genomic segment in tobacco varieties that are resistant to potato virus Y (PVY)

Recessive alleles (va, va ¹ , va ² , etc) of the tobacco Va locus confer resistance to potato virus Y (PVY). To elucidate the mechanism underlying this resistance, we attempted to identify randomly amplified polymorphic (RAPD) markers that reveal polymorphism between two nearly isogenic lines (NILs) that differ in their susceptibility to PVY. Using each of 500 primers and 800 pairs of primers, we identified over 100 RAPD fragments that differed between the NILs. We applied these RAPD primers or primer combinations to an F₂ population obtained from a cross between the susceptible line BY4 and the resistant va ² -bearing NIL, F55. It was found that only 10 RAPD markers were polymorphic between resistant and susceptible plants. Unexpectedly, these markers were all linked to Va. All 10 RAPD markers were present in all 8 susceptible varieties tested. At least one RAPD marker was not detected in 8 out of 10 resistant varieties. Southern analysis revealed that the sequences of markers were not present in the genomes of resistant varieties, and the markers were found in individually distinct positions on the chromosomes of susceptible tobacco varieties. These results strongly suggest that the resistance conferred by va is due to deletions at the Va locus governing susceptibility to PVY. Received: 20 May 1999 / Accepted: 17 August 1999     

红豆杉科植物RAPD分析及其系统学意义

利用随机扩增多态性ＤＮＡ（ＲＡＰＤ）技术分析了红豆杉科（Ｔａｘａｃｅａｅ）红豆杉属（Ｔａｘｕｓ）、白豆杉属（Ｐｓｅｕｄｏｔａｘｕｓ）、穗花杉属（Ａｍｅｎｔｏｔａｘｕｓ）和榧树属（Ｔｏｒｒｅｙａ）的６种植物：红豆杉（Ｔａｘｕｓ ｃｈｉｎｅｎｓｉｓ （Ｐｉｌｇｅｒ）Ｒｅｈｄ）、南方红豆杉（Ｔａｘｕｓ ｃｈｉｎｅｎｓｉｓ ｖａｒ．ｍａｉｒｅｉ（Ｌｅｍｅｅ ｅｔＬｅｖｌ．）Ｃｈｅｎｇ ｅｔＭａｉｒｅＹｅｗ     

应用RAPD标记技术对树鼩遗传多样性的分析

目的建立树鼩RAPD（random amplified polymorphic DNA）遗传标记分析方法,了解中缅树鼩种群的遗传多样性。方法采用PCR技术对40条随机引物进行优化,筛选出能有效用于树鼩群体遗传分析的RAPD位点,对48只树鼩个体的基因组DNA进行PCR扩增,并应用Popgene 1.32与RAPDistance Package Version 1.04等软件进行数据处理,分析树鼩的群体遗传特性。结果20个RAPD引物共检测到113个位点,平均每个引物可扩增出5.65个位点,其中多态位点数为69个（占61.1%）。个体间的遗传相似系数平均为0.8307,个体间遗传距离在0.09-0.27之间,平均遗传距离为0.1693。雄性群体的遗传多态度（H0）（0.1864）略高于雌性群体（0.1470）,平均遗传多态度（Hpop）为0.1667;树鼩遗传多态度所占的比例在群体内为48.29%,而雌、雄群体间为51.71%。NJ法进行聚类分析得出T15、T33和T47号树鼩个体聚类成一大类,其余45只树鼩个体聚成另一大类,雌、雄个体呈相互交叉现象。结论实验所筛选的随机引物可有效用于中缅树鼩种群的遗传结构分析。本树鼩群体具有较好的遗传多样性。     

Inter- and intraspecific genetic variation inHippophae (Elaeagnaceae) investigated by RAPD markers

Genetic diversity has been investigated by the application of molecular markers in, for the first time, all the taxa recognised in recent treatises of the genusHippophae. RAPD (random amplified polymorphic DNA) analyses were conducted with 9 decamer primers, which together yielded 219 polymorphic markers. We found 16 fixed RAPD markers, i.e. markers that either occurred in all plants of a population or were absent from all plants. Several of these markers were useful for analysis of interspecific relationships, whereas others can be considered as taxon-specific markers. Clustering of taxa and populations in our neighbour-joining based dendrogram was in good agreement with some recently suggested taxonomic treatises ofHippophae. Amount and distribution of genetic variability varied considerably between species. Partitioning of molecular variance withinH. rhamnoides supported earlier findings that a considerable part of the total variance resides among subspecies (59.6%) Within-population variability also differed considerably. Percentage polymorphic RAPD loci and Lynch and Milligan within-population gene diversity estimates showed relatively high values for some species close to the geographic centre of origin in Central Asia, e.g.H. tibetana and the putatively hybridogenousH. goniocarpa. Spatial autocorrelation analyses performed on 12 populations ofH. rhamnoides revealed positive autocorrelation of allele frequencies when geographic distances ranged from 0 to 700 km, and no or negative autocorrelation at higher distances. At distances between 700 and 1900 km, we observed deviations from the expected values with strongly negative autocorrelation of allele frequencies. A corresponding relationship between geographic and genetic distances could not be found when the analysis instead was based on one population from each of 8 species.     

Evaluation of genetic diversity of <Emphasis Type="Italic">Clinacanthus nutans</Emphasis> (Acanthaceaea) using RAPD,ISSR and RAMP markers

Three polymerase chain reaction (PCR) techniques were compared to analyse the genetic diversity of Clinacanthus nutans eight populations in the northern region of Peninsular Malaysia. The PCR techniques were random amplified polymorphic deoxyribonucleic acids (RAPD), inter-simple sequence repeats (ISSR) and random amplified microsatellite polymorphisms (RAMP). Leaf genomic DNA was PCR amplified using 17 RAPD, 8 ISSR and 136 RAMP primers . However, only 10 RAPD primers, 5 ISSR primers and 37 RAMP primers produced reproducible bands. The results were evaluated for polymorphic information content (PIC), marker index (MI) and resolving power (RP). The RAMP marker was the most useful marker compared to RAPD and ISSR markers because it showed the highest average value of PIC (0.25), MI (11.36) and RP (2.86). The genetic diversity showed a high percentage of polymorphism at the species level compared to the population level. Furthermore, analysis of molecular variance revealed that the genetic diversity was higher within populations, as compared to among populations of C. nutans. From the results, the RAMP technique was recommended for the analysis of genetic diversity of C. nutans.     

Efficiency of phenotypic and DNA markers for a genetic diversity study of alfalfa

Information on genetic diversity and germplasm characterization is essential for successful crop improvement. Diverse data sets (pedigree, morphological, biochemical, DNA based-markers) are employed in various aspects of plant analysis. The objective of this study was to determine the efficiency of phenotypic and RAPD markers in diversity assessment of ten alfalfa (Medicago spp.) accessions from Europe, North America and Australia. Field experiment was designed as a randomised complete block with three replications over two consecutive years (2004, 2005) at one location. Twelve morpho-agronomic traits were recorded on 50 plants per each accession. Genomic DNA’s from 16–20 randomly selected individual plants per accession were used for RAPD analysis. Six primers selected in this study generated a total of 93 polymorphic RAPD bands. The number of polymorphic bands detected per primer ranged from 11 to 20. Genetic distances (GD) among investigated accessions and two-dimensional principal coordinate analysis (2D PCoA) based on phenotypic and molecular data were obtained. The average GD between (0.283–0.416) and within (0.247–0.332) accessions based on RAPD data was higher than GD values obtained by morpho-agronomic traits (0.171–0.354 and 0.157–0.261, respectively). 2D PCoA based on GD from RAPD data grouped most of the studied individual plants to four clusters according to their geographical or taxonomy origin. 2D PCoA based only on morpho-agronomic data did not group plants congruently to their origin, probably due to a strong environmental influence on studied traits. Our results indicated that the RAPD markers were effective in assessing genetic diversity within and between studied alfalfa accessions. In addition, the obtained results suggested that the RAPD markers might be useful for grouping of germplasm with similar genetic background and for pre-screening of potential heterotic groups in our breeding programme.     

R-ISSR marker as a useful tool for detection of new genomic loci in <Emphasis Type="Italic">Arthrocnemum macrostachyum</Emphasis>

Arthrocnemum macrostachyum, is a perennial halophytic shrub typical of Mediterranean salt marshes. The present study aims to investigate some combinations of inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) primers applied in real PCR. Thereby, the potential of R-ISSR markers to detect new genomic loci in 3 genotypes of A. macrostachyum grown in the Western coast of Syria was examined. Different combinations of RAPD and ISSR primers produced bands that were absent when single ISSR or RAPD primers were used. The results have demonstrated that ISSR primer (AG)₈TC gave more informative pattern when combined with different RAPD primers comparing to other tested primers. In contrast, the tested ISSR primer (GACA)₄ gave less informative pattern when used alone. These combinations were successfully applied in real PCR to detect new genomic variability in A. macrostachyum genotypes.     

Morphological and molecular characterisation of Pythium species causing chilli (Capsicum annuum L.) damping-off

Twenty-five Pythium isolates comprising five species viz., Pythium aphanidermatum, P. deliense, P. graminicola, P. heterothallicum and P. ultimum from different geographical locations of Tamil Nadu (Coimbatore, 4; Cuddalore, 6; Dindigul, 1; Dharmapuri, 1; Erode, 1; Madurai, 1; Namakkal, 7; Thanjavur, 1; Theni, 1; Thirunelveli, 1 and Vellore, 1) isolated from chilli crop were analysed with randomly amplified polymorphic DNA (RAPD) markers. Morphological and molecular characteristics of these different species were correlated with the RAPD. Polymerase chain reaction amplification of total genomic DNA with six random primers generated unique banding patterns depending on the primer and the isolate. The isolate I₁₇ produced identical banding patterns, while other isolates produced dissimilar bands within the particular species, indicating the genetic diversity among the isolates within a species. Morphological characters were also different from each other even in isolate I₁₇ which shared identical bands. Cluster analysis showed minimum and maximum per cent similarities among the tested Pythium species which ranged from 49 to 89%, respectively. RAPD markers were better suited for differentiating isolates within a species rather than species.     

Characterization of Fusarium oxysporum Isolates from Common Bean and Sugar Beet Using Pathogenicity Assays and Random-amplified Polymorphic DNA Markers

Fusarium wilt is an economically important fungal disease of common bean and sugar beet in the Central High Plains (CHP) region of the USA, with yield losses approaching 30% under appropriate environmental conditions. The objective of this study was to characterize genetic diversity and pathogenicity of isolates of Fusarium oxysporum obtained from common bean and sugar beet plants in the CHP that exhibited Fusarium wilt symptoms. A total of 166 isolates of F. oxysporum isolated from diseased common bean plants were screened for pathogenicity on the universal susceptible common bean cultivar ‘UI 114’. Only four of 166 isolates were pathogenic and were designated F. oxysporum f.sp. phaseoli (Fop). A set of 34 isolates, including pathogenic Fop, F. oxysporum f.sp. betae (Fob) isolates pathogenic on sugar beet, and non‐pathogenic (Fo) isolates, were selected for random‐amplified polymorphic DNA (RAPD) analysis. A total of 12 RAPD primers, which generated 105 polymorphic bands, were used to construct an unweighted paired group method with arithmetic averages dendrogram based on Jaccard's coefficient of similarity. All CHP Fop isolates had identical RAPD banding patterns, suggesting low genetic diversity for Fop in this region. CHP Fob isolates showed a greater degree of diversity, but in general clustered together in a grouping distinct from Fop isolates. As RAPD markers revealed such a high level of genetic diversity across all isolates examined, we conclude that RAPD markers had only limited usefulness in correlating pathogenicity among the isolates and races in this study.     

Efficiency of ISSR and RAPD markers in genetic divergence analysis and conservation management of Justicia adhatoda L., a medicinal plant

Genetic variation within and among population is the basis for survival of the population both in short and long term. Thus, studying the plant genetic diversity is essential for any conservation program. Indigenous medicinal plants like Justicia adhatoda L. which are facing high rate of depletion from the wild population need immediate attention. DNA-based dominant molecular marker techniques, random amplification of polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) were used to unravel the genetic variability and relationships across thirty-two wild accessions of J. adhatoda L., a valuable medicinal shrub widespread throughout the tropical regions of Southeast Asia. Amplification of genomic DNA using 38 primers (18 RAPD and 20 ISSR) yielded 434 products, of which 404 products were polymorphic revealing 93.11 % polymorphism. The average polymorphic information content value obtained with RAPD and ISSR markers was 0.25 and 0.24, respectively. Marker index (RAPD = 3.94; ISSR = 3.53) and resolving power (RAPD = 4.24; ISSR = 3.94) indicate that the RAPD markers were relatively more efficient than the ISSR assay revealing the genetic diversity of J. adhatoda. The Shannon diversity index obtained with RAPD and ISSR markers was 0.40 and 0.38, respectively. The similarity coefficient ranged from 0.26 to 0.89, 0.33 to 0.93 and 0.31 to 0.90 with RAPD, ISSR and combined UPGMA dendrogram, respectively. PCA derived on the basis of pooled data of both the markers illustrated that the first three principal coordinate components accounted 79.27 % of the genetic similarity variance. The mantel test between two Jaccard’s similarity matrices gave r = 0.901, showing the fit correlation between ISSR- and RAPD-based similarities. Based on the results, ex-situ methods may be the most suitable and efficient measure for long-term conservation.     

Genetic Diversity of Radish (Raphanus sativus L.) Germplasm Resources Revealed by AFLP and RAPD Markers

Genetic diversity of 56 radish accessions, representing nearly all the typical types and origins of cultivated radish germplasms conserved in the National Mid-term Genebank for Vegetables of China, was assessed with amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) markers. A total of 72 and 128 polymorphic bands were generated by the 12 selected RAPD primers and eight AFLP primer combinations respectively. A moderate correlation with the value of r = 0.66 was observed between AFLP and RAPD markers. The total 200 polymorphic bands were integrated to assess the genetic diversity of 56 radish accessions. The Jaccard similarity coefficients between the accessions varied from 0.30 to 0.83 with the mean of 0.54. Cluster analysis classified the germplasms into three groups of var. hortensis Becker, var. sativus, and var. niger Kerner. The three-dimensions scatter plot of principle coordinate analysis (PCA) further divided var. hortensis Becker germplasms into two separate groups. The results indicated that the genetic diversity harbored among var. hortensis Becker germplasms was very abundant, which could be further exploited for radish genetic improvement.     

Genetic diversity in natural populations of Jacaranda decurrens Cham. determined using RAPD and AFLP markers

Jacaranda decurrens (Bignoniaceae) is an endemic species of the Cerrado with validated antitumoral activity. The genetic diversity of six populations of J. decurrens located in the State of São Paulo was determined in this study by using molecular markers for randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP). Following optimization of the amplification reaction, 10 selected primers generated 78 reproducible RAPD fragments that were mostly (69.2%) polymorphic. Two hundred and five reproducible AFLP fragments were generated by using four selected primer combinations; 46.3% of these fragments were polymorphic, indicating a considerable level of genetic diversity. Analysis of molecular variance (AMOVA) using these two groups of markers indicated that variability was strongly structured amongst populations. The unweighted pair group method with arithmatic mean (UPGMA) and Pearson''s correlation coefficient (RAPD -0.16, p = 0.2082; AFLP 0.37, p = 0.1006) between genetic matrices and geographic distances suggested that the population structure followed an island model in which a single population of infinite size gave rise to the current populations of J. decurrens, independently of their spatial position. The results of this study indicate that RAPD and AFLP markers were similarly efficient in measuring the genetic variability amongst natural populations of J. decurrens. These data may be useful for developing strategies for the preservation of this medicinal species in the Cerrado.