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.     

Evaluation of genetic relationship in Typhonium species through random amplified polymorphic DNA markers

Studies were undertaken to identify genetic relationships in three species of Typhonium and to evaluate the genetic variance within populations of Typhonium trilobatum, Typhonium roxburghii and Typhonium flagelliforme by using random amplified polymorphic DNA (RAPD) markers. A total of 193 distinct DNA fragments ranging from 0.2 to 3.2 kb, were amplified using 22 selected random decamer primers. The cluster analysis indicated that the three species of Typhonium formed two clusters: the first one consisted of T. trilobatum and T. roxburghii, the second one was represented by T. flagelliforme. A maximum similarity of 63 % was observed in T. trilobatum and T. roxburghii. T. flagelliforme shared up to 43 % similarity with T. trilobatum and T. roxburghii. The closest genetic distance was obtained within populations of different Typhonium species.     

Genetic Relationships among Far Eastern Species of the Family Araliaceae Inferred by RAPD Analysis

A molecular genetic study of Far Eastern species of the family Araliaceae by means of RAPD analysis was conducted. Using 21 primers we assessed variability at 595 loci. Based on matrices of genetic distances D, dendrograms of genetic relationships among eleven species of this family were constructed. Our results suggest that Acanthopanax sessiliflorus and Eleutherococcus senticosus belong to different genera, Aralia cordata andA. continentalis are different species, and A. elata and A. mandshurica probably cannot be regarded as distinct species. Genetic similarity of Far Eastern A. cordata and American A. hispida is shown.     

Genetic variability among Alexandrium tamarense and Alexandrium minutum strains studied by RAPD banding pattern analysis

We performed random amplification of polymorphic DNA (RAPD) analysis on five strains of Alexandrium tamarense and nine strains of Alexandrium minutum. Arbitrary 10-mer oligonucleotides were used as primers for the PCR. Electrophoresis on denaturing acrylamide gels improved RAPD reproducibility and increased the band number. Eight of the 20 primers assayed gave reproducible results and the band profiles generated by them were used for constructing a similarity matrix. Analyses were performed independently for the strains of each species and jointly for all the strains of both species. Results for A. tamarense showed the highest similarity for two distinct clones isolated from the same water sample in the Baltic Sea during a bloom (KAC01 and KAC02). The highest similarity among A. minutum clones was found for three strains (AL1V, AL2V and AL3V) isolated in the Ria de Vigo in NW Spain. The results show a high genetic diversity within a single species. We have shown the potential of the RAPD technique to discriminate between two conspecific strains, as well as for establishing similarities that are related to the biogeographic origin of the strains.     

25份槭属优良种质资源亲缘关系的ISSR分析

槭属植物是世界园林绿化中的重要植物种类,种质资源丰富且大多数种类具有重要的观赏价值。针对目前我国槭属植物杂交育种工作中面临的品种混杂不清、亲缘状况不明等情况,该研究采用ISSR分子标记对槭属25份植物材料进行了亲缘关系分析。结果表明:选用12条扩增带型清晰且重复性好的引物共获得84条谱带,其中81条呈多态性,多态性比例(PPB)达96.43%,表明槭属植物遗传多样性较高。25份槭属植物材料的遗传相似性系数介于0.405与0.952之间,平均值为0.627,表明不同品种或物种之间遗传相似性系数变化较大。根据Nei遗传相似性系数,在0.578处,UPGMA结果将25份植物材料分为2个类群,其中鸡爪槭品种(或变种)聚为一类,显示了各品种(或变种)之间具有较高的亲缘关系,其余槭属植物则聚为类群II;在0.646处,可进一步分为6个亚类群,部分鸡爪槭品种间表现出了叶形、叶色等表型形状与其遗传关系的相关性。研究未发现鸡爪槭品种(或变种)的亲缘关系与地理分布存在相关性。我国槭树资源丰富,但目前我国对槭树新品种的开发及选育工作仍十分薄弱,建议采取自行选育结合国外引进新品种的方式,丰富我国的槭树种质资源。     

Phylogenetic relationships and gene flow between sympatric diploid and tetraploid plants ofDactylis glomerata (Gramineae)

Phylogenetic relationships between sympatric, morphologically indistinguishable diploid and tetraploid plants ofDactylis glomerata L. (Gramineae) in Galicia (Spain) were assessed using allozyme markers for 6 distinct systems. The study exploited recent introduction in Galicia and subsequent hybridization of an alien 4xDactylis subspecies possessing distinct allozymes from those of all the native plants. Opportunities for gene exchanges between the ploidies were estimated from in situ observations of flowering, examination of progenies in 2x/4x natural and experimental crosses, and enzyme analyses. Results show a high genetic similarity between the Galician diploids and tetraploids, which possess peculiar alleles in common. Although the ploidy levels usually have distinct flowering periods, interploidal crosses do occasionally occur. Gene flow is likely much more important from the diploid to the tetraploid level. A good genetic intermixing occurs between the Galician and the alien tetraploid entities which have simultaneous flowering. Autopolyploidization of the diploids followed by various rates of hybridization is proposed as one very probable origin of natural tetraploids inDactylis.     

Allozyme variation and population differentiation of the Aconitum delavayi complex (Ranunculaceae) in the Hengduan Mountains of China

The Aconitum delavayi complex is a group of four climbing species with trisect-leaves occurring in the Hengduan Mountains. The species of this complex are highly localized on very narrow regions with quite small population sizes. Because of rapid environmental changes recently in the Hengduan Mountains, this complex shows complicated morphological variability, which makes it difficult to delimit species. In the present study, 10 enzyme systems coding for 14 putative loci were employed to detect the interspecific and intraspecific genetic variation of the complex. In addition to low genetic diversity within all eight populations surveyed, the results indicate that A. episcopale is a distinct species because of high genetic identities among its three populations. Very low genetic divergence among populations of A. stapfianum and A. delavayi suggests that the two species should be treated as a single one.     

Investigating niche and lineage diversification in widely distributed taxa: phylogeography and ecological niche modeling of the Peromyscus maniculatus species group

The relationship between lineage formation and variation in the ecological niche is a fundamental evolutionary question. Two prevailing hypotheses reflect this relationship: niche conservatism and niche divergence. Niche conservatism predicts a pattern where sister taxa will occupy similar niche spaces; whereas niche divergence predicts that sister taxa will occupy different niche spaces. Widely distributed species often show distinct phylogeographic structure, but little research has been conducted on how the environment may be related to these phylogenetic patterns. We investigated the relationship between lineage divergence and environmental space for the closely related species Peromyscus maniculatus and P. polionotus utilizing phylogenetic techniques and ecological niche modeling (ENM). We estimated the phylogenetic relationship among individuals based on complete cytochrome b sequences that represent individuals from a majority of the species ranges. Niche spaces that lineages occupy were estimated by using 12 environmental layers. Differences in niche space were tested using multivariate statistics based on location data, and ENMs were employed using maximum entropy algorithms. Two similarity indices estimated significant divergence in environmental space based on the ENM. Six geographically structured lineages were identified within P. maniculatus. Nested within P. maniculatus we found that P. polionotus recently diverged from a clade occupying central and western United States. We estimated that the majority of the genetic lineages occupy distinct environmental niches, which supports a pattern of niche divergence. Two sister taxa showed niche divergence and represent different ecomorphs, suggesting morphological, genetic and ecological divergence between the two lineages. Two other sister taxa were observed in the same environmental space based on multivariate statistics, suggesting niche conservatism. Overall our results indicate that a widely distributed species may exhibit both niche conservatism and niche divergence, and that most lineages seem to occupy distinct environmental niches.     

Spatial analysis of taxonomic and genetic patterns and their potential for understanding evolutionary histories

Aim The aim of this research is to develop and investigate methods for the spatial analysis of diversity based on genetic and taxonomic units of difference. We use monophyletic groups of species to assess the potential for these diversity indices to elucidate the geographical components of macro‐scaled evolutionary processes. Location The range occupied by Pultenaea species in temperate and sub‐tropical eastern Australia, extending from western South Australia (133° E–32° S) to Tasmania (146° E–43° S) to coastal central Queensland (148° E–20° S). Methods We applied a series of both spatially explicit and spatially implicit analyses to explore the nature of diversity patterns in the genus Pultenaea, Fabaceae. We first analysed the eastern species as a whole and then the phylogenetic groups within them. We delineated patterns of endemism and biotic (taxon) regions that have been traditionally circumscribed in biogeographical studies of taxa. Centres of endemism were calculated using corrected weighted endemism at a range of spatial scales. Biotic regions were defined by comparing the similarity of species assemblages of grid cells using the Jaccard index and clustering similar cells using hierarchical clustering. On the basis that genetically coherent areas were likely to be more evolutionary informative than species patterns, genetic indices of similarity and difference were derived. A matrix of similarity distances between taxa was generated based on the number of shared informative characters of two sections of trnL‐F and ndhF chloroplast nuclear regions. To identify genetically similar areas, we clustered cells using the mean genetic similarities of the species contained within each pair of cells. Measures of the mean genetic similarity of species in areas were delineated using a geographically local multi‐scalar approach. Resultant patterns of genetic diversity are interpreted in relation to theories of the evolutionary relationships between species and species groups. Results Centres of Pultenaea endemism were defined, those of clades 1 congruent with the spatially separated centres of clades 2 and 3. The taxonomic classification analysis defined cells with shared groups of species, which in some cases clustered when plotted in geographic space, defining biotic regions. In some instances the distribution of biotic regions was congruent with centres of endemism, however larger scale groupings were also apparent. In clade 1 one set of species was replaced by another along the extent of the range, with some connectivity between some geographically disjunct regions due to the presence of widespread species. In the combined analysis of clade 2 and 3 species the major biotic (taxonomic) groups with geographic coherence were defined by species in the respective clades, representing the geographic separation of these clades. However distinctive biotic regions within these main groupings of clades 2 and 3 were also apparent. Clustering cells using the mean genetic similarities of the species contained within each pair of cells indicated that some of the taxonomically defined biotic boundaries were the result of changes in composition of closely related species. This was most apparent in clades 1 and 2 where most cells were highly genetically similar. In clade 3 genetically distinct groups remained and were in part defined by sister taxa with disjunct distributions. Gradients in mean genetic similarity became more apparent from small to larger scales of analysis. At larger scales of analysis, regions of different levels of genetic diversity were delineated. Regions with highest diversity levels (lowest level of similarity) often represented regions where the ranges of phylogenetically distinctive species intergraded. Main conclusions The combined analysis of diversity, phylogeny and geography has potential to reveal macro‐scaled evolutionary patterns from which evolutionary processes may be inferred. The spatial genetic diversity indices developed in this study contribute new methods for identifying coherent evolutionary units in the landscape, which overcome some of the limitations of using taxonomic data, and from which the role of geography in evolutionary processes can be tested. We also conclude that a multiple‐index approach to diversity pattern analysis is useful, especially where patterns may be the result of a long history of different environmental changes and related evolutionary events. The analysis contributes to the knowledge of large‐scale diversity patterns of Pultenaea which has relevance for the assessment of the conservation status of the genus.     

Molecular phylogeny of Gossypium species by DNA fingerprinting

Total genomic DNA from 31 available Gossypium species, three subspecies and one interspecific hybrid, were analysed to evaluate genetic diversity by RAPD, using 45 random decamer primers. A total of 579 amplified bands were observed, with 12.9 bands per primer, of which 99.8% were polymorphic. OPJ-17 produced the maximum number of fragments while the minimum number of fragments was produced with primer OPA-08. Cluster analysis by the unweighted paired group method of arithmetic means (UPGMA) showed six main clusters. Cluster ’A’ consisted of two species and one subspecies of the A-genome, with a 0.78–0.92 Nei’s similarity range. Cluster B, composed of all available tetraploid species and one interspecific hybrid, showed the same sister cluster. Nei’s similarity ranged from 0.69 to 0.84. The B-genome formed the UPGMA sister cluster to the E-genome species. Cluster ’C’ consisted of five Gossypium species of which three belong to the B-genome, with Nei’s similarity values of 0.81 to 0.86. Although there was considerable disagreement at lower infra-generic ranks, particularly among the D- genome (diploid New World species) and C-genome (diploid Australian species) species. The sole F-genome species Gossypium longicalyx was resolved as a sister group to the D-genome species. Gossypium herbaceum and G. herbaceum Africanum showed the maximum Nei’s similarity (0.93). Minimum similarity (0.29) was observed between Gossypium trilobum and Gossypium nelsonii. The average similarity among all studied species was 50%. The analysis revealed that the interspecific genetic relationship of several species is related to their centre of origin. As expected, most of the species have a wide genetic base range. The results also revealed the genetic relationships of the species Gossypium hirsutum to standard cultivated Gossypium barbadense, G. herbaceum and Gossypium arboreum. These results correspond well with previous reported results. The level of variation detected in closely related genotypes by RAPD analysis indicates that it may be a more efficient marker than morphological marker, isozyme and RFLP technology for the construction of genetic linkage maps. Received: 2 January 2000 / Accepted: 12 February 2000     

Ecological genetics of the cave beetle Neaphaenops tellkampfii (Coleoptera: Carabidae)

Summary Genetic variability and similarity were examined in eight populations of the Kentucky cave beetle Neaphaenops tellkampfii (Coleoptera: Carabidae) using the technique of polyacrylamide gel electrophoresis. Results indicate that N. tellkampfii has high genetic variation within and high genetic similarity among local populations. These results are in sharp contrast to the patterns of low variability and similarity reported for other cave dwelling species in the same region. It is concluded that the differences in genetical population structure among cave species in the Central Kentucky Karst are related to ecological differences among the species.     

Identification of Prosopis juliflora and Prosopis pallida Accessions Using Molecular Markers

There has been much taxonomic confusion over the identification of Prosopis species, especially where introduced. Prosopis juliflora is the most widespread species in the arid and semi-arid tropics, although it has been confused with other species, particularly the closely related Prosopis pallida. In this study, RAPDs markers were used for the first time to distinguish between these species. Eighteen primers were used in amplification reactions, which yielded an average of 120 bands per accession. A dendrogram showing genetic similarities among accessions was constructed using UPGMA cluster analysis and the Nei and Li similarity coefficient. The genetic similarity observed between P. juliflora and P. pallida is similar to the value in sympatric Prosopis species in North America, and reconsideration of the series rank in section Algarobia is suggested. Species-specific markers confirmed that material in Burkina Faso is P. juliflora, but suggested that material collected in Brazil, Cape Verde and Senegal is P. pallida, whereas this has previously been identified as P. juliflora.     

Genetic and behavioral components of the cryptic species boundary between Laupala cerasina and L. kohalensis (Orthoptera: Gryllidae)

Cryptic species are often hypothesized on the basis of differences in courtship signals. These signal differences suggest that mate recognition systems, which include both courtship signals and responses to those signals, have diverged between genetically isolated populations. Cryptic species are therefore thought to represent distinct genetic units, the boundaries of which are maintained by premating incompatibilities, specifically by receiver preferences for conspecific signals. Laupala cerasina and L. kohalensis are sympatric species of swordtail crickets endemic to the big island of Hawaii, that are distinguishable by differences in male courtship song. We first tested whether groupings hypothesized by acoustic similarity reflect genetic groupings, using AFLP data to estimate genetic relationships. Second, we tested whether genetic boundaries are maintained by female preferences for conspecific song characteristics. Phonotaxis trials were used to determine the extent of female preferences for conspecific male song. Results generally support both hypotheses, but suggest the presence of porous species boundaries.     

Genetic diversity analysis of Rhodothermus reflects geographical origin of the isolates

The genetic diversity and relationships of 81 Rhodothermus isolates from different geothermal environments in Iceland were examined by analysis of electrophoretically demonstrable allelic variation of 13 genes encoding enzymes. All the enzymes were polymorphic. A total of 71 distinctive multilocus genotypes (electrophoretic types, ETs) were identified. The mean genetic diversity per locus (H _t ) was 0.586. The relatively high genetic variance observed within Rhodothermus isolates from different locations is most likely the result of genetic changes occurring independently in the locations studied. A high G _st value (0.284) indicates that a considerable part of the variance observed is due to differences between locations. Cluster analysis revealed two major groups of ET clusters diverging at a genetic distance of 0.75, reflecting strongly the geographic origin of isolates. Estimation of the association index (I _A) indicates that Rhodothermus marinus is a clonal species in which recombination events occur rarely. Partial or whole sequencing of the 16S rRNA genes of Rhodothermus isolates grouping at genetic distance of 0.40 confirmed that all the isolates belonged to the species Rhodothermus marinus. The results of this study confirm that, despite phylogenetic and phenotypic similarity, genetic diversity within Rhodothermus marinus is quite high. Received: January 21, 2000 / Accepted: April 27, 2000     

Restriction Endonuclease Analysis of Mitochondrial DNA as an Aid in the Taxonomy of Naegleria and Vahlkampfia1

ABSTRACT Using restriction enzyme analysis, mitochondrial DNA fragment patterns from seven strains of pathogenic and nonpathogenic Naegleria and one strain of Vahlkampfia were compared to estimate nucleotide sequence divergence. Significantly high levels of estimated genetic variation between strains of N. gruberi, N. fowleri, and N. jadini support the current taxonomic level of the individual Naegleria species and suggest a distinct phylogeny for each group. Naegleria lovaniensis, strain TS, was shown to have significant nucleotide sequence homology with N. gruberi, strain EGs, suggesting that the two groups share a close taxonomic relationship. The pathogenic strain MB-41 of N. fowleri exhibited distinct genetic divergence from the highly homologous, pathogenic strain Nf66 and the drug-cured strain 6088. Morphologically distinct strains EGs and 1518/la of N. gruberi exhibited significantly large sequence divergence consistent with a more distant taxonomic relationship. Amoebae from the genus Vahlkampfia expressed genetic similarity with strains of N. gruberi.     

QUANTITATIVE GENETICS OF MORPHOLOGICAL DIFFERENTIATION IN PEROMYSCUS. I. TESTS OF THE HOMOGENEITY OF GENETIC COVARIANCE STRUCTURE AMONG SPECIES AND SUBSPECIES

Phenotypic and additive genetic covariance matrices were estimated for 15 morphometric characters in three species and subspecies of Peromyscus. Univariate and multivariate ANOVAs indicate these groups are highly diverged in all characters, P. leucopus having the largest body size, P. maniculatus bairdii the smallest, and P. maniculatus nebrascensis being intermediate. Comparing the structure of P and G within each taxon revealed significant similarities in all three cases. This proportionality was strong enough to justify using P in the place of G to analyze evolutionary processes using quantitative genetic models when G can not be estimated, as in fossil material. However, the similarity between genetic and phenotypic covariance structures is sufficiently low that estimates of the genetic parameters should be used when possible. The additive genetic covariance matrices were compared to examine the assumption that they remain constant during evolution, an assumption which underlies many applications of quantitative-genetic models. While matrix permutation tests indicated statistically significant proportionality between the genetic covariance structures of the two P. maniculatus subspecies, there is no evidence of significant genetic structural similarity between species. This result suggests that the assumption of constant genetic covariance structure may be valid only within species. (It does not, however, necessarily imply a causal relationship between speciation and heterogeneity of genetic covariance structures.) The low matrix correlation for the two P. maniculatus subspecies' genetic covariance matrices indicates G may not be functionally constant, even within species. The lack of similarity observed here may be due partly to sampling variation.     

Molecular diversity and relationships of North American Elymus trachycaulus and the Eurasian E. caninus species

The morphological similarity of Elymus trachycaulus to the Eurasian E. caninus has often been noted. This has lead to controversial and contradicting taxonomic treatments. Nevertheless, there has been no systematic investigation on molecular genetic similarity between E. trachycaulus and E. caninus. In this study, random amplified polymorphic DNA (RAPD) analysis was used to study the similarity between the two species. RAPD analysis of 38 samples representing E. caninus and E. trachycaulus complex yielded 111 interpretable RAPD bands. The Jaccard’s similarity values for E. caninus ranged from 0.38 between accessions H10345 and H10353 to 0.97 between accessions H8745 and H10096, with an average of 0.67. The Jaccard’s similarity values for E. trachycaulus complex ranged from 0.09 between E. trachycaulus ssp. subsecundus (PI 537321) and E. trachycaulus ssp. violaceus (PI 272612) to 0.78 between accessions PI 315368 and PI 372644, with an average of 0.43. The results from different analyses (NJ and PCA) were similar but not identical. The molecular genetic separation between E. caninus and E. trachycaulus was consistent. The PCA analysis clearly separated all E. caninus accessions from E. trachycaulus and its subspecies. The NJ analysis also showed separation between most accessions of E. caninus and E. trachycaulus. Further analysis excluding E. trachycaulus ssp. subsecundus and ssp. violaceus revealed that E. caninus species and E. trachycaulus species were clearly separated into two distinct groups. The RAPD data thus support the treatment of E. caninus and E. trachycaulus as distinct species. The analyses further indicate that E. violaceus is nested within E. trachycaulus, and more related to E. trachycaulus complex rather than to E. caninus.     

Genetic diversity of <Emphasis Type="Italic">Caragana</Emphasis> species of the Ordos Plateau in China

Plants of the genus Caragana (Fabaceae) are dominant shrub species of high ecological and economic importance on the Ordos Plateau in China. Due to natural environmental variability and anthropogenic impacts, Caragana pastures have experienced severe degradation, which has decreased their carrying capacity. In this study, we investigated the genetic diversity of eight Caragana species (C. purdomii, C. opulens, C. stenophylla, C. intermedia, C. korshinskii, C. roborovskyi, C. tibetica and C. brachypoda) on the Ordos Plateau by using ISSR markers. The results reveal high genetic diversity of all the species, with the percentage of polymorphic bands (PPB) reaching 100%. However, interspecific differences in genetic diversity within the genus were significant, as indicated by higher levels of genetic diversity of C. stenophylla, C. tibetica, C. intermedia, C. korshinskii and C. roborovskyi (PPB > 86%) when compared to the C. brachypoda with the lowest genetic diversity (PPB = 42.86%). Caragana brachypoda showed the lowest genetic similarity with and largest genetic distance from other taxa of the genus. Caragana tibetica had higher genetic diversity than C. roborovskyi. A large genetic distance was found between C. roborovskyi and C. tibetica, although the two species belong to Ser. Tragacanthoides and grow in a semidesert area. Such differences in genetic structure may be the reason for large areas occupied by C. tibetica, whereas C. roborovsky has rather limited distribution in the semidesert area. Caragana intermedia had high genetic diversity and a large genetic differentiation between intraspecific populations implying strong adaptability of the species to environmental fluctuations and selection capabilities. There was an obvious gene flow between C. intermedia and C. korshinskii, suggesting possible hybridization between these species is consistent with ecological variability, which may be important characteristics of Caragana plants in terms of molecular variation in the ecotone of Ordos plateau. Our results provide a molecular basis for sustainable management, utilization and conservation of Caragana plants on the Ordos plateau.     

Random amplified polymorphic DNA (RAPD) markers reveal genetic homogeneity in the endangered Himalayan species Meconopsis paniculata and M. simplicifolia

Random amplified polymorphic DNA (RAPD) marker-based analysis was carried out to study the extent of genetic polymorphism between populations of the two endangered Himalayan poppy species, Meconopsis paniculata and M. Simplicifolia. Of the 90 primers tested, 38 revealed marked inter-species genetic polymorphism between individuals of the two species from geographically isolated populations. However, intra-species genetic homogeneity was also evident with respect to a number of primers both within and between populations. A comprehensive analysis incorporating data from RAPDs, DNA fingerprinting and isozyme pattern was carried out and, based on the presence or absence of bands, three matrices of similarity indices were estimated. These matrices were subsequently utilized in cluster analysis. In order to compare the three clusters generated using these three different marker systems, a Mantel matrix-correspondence test was carried out on the basis of comparisons of co-phenetic values. The overall representation of relationships by cluster analysis was similar for all three marker systems and this was substantiated by high correlations among the three analyses revealed by the Mantel matrix-correspondence test. Our results point to very low or absence of, genetic polymorphism in M. paniculata and M. simplicifolia, and are in broad agreement with our previous observations on genetic diversity of Meconopsis species which point to a genetic basis for the possible extinction of this economically important genus.     

Analysis of the genetic diversity of physic nut, <Emphasis Type="Italic">Jatropha curcas</Emphasis> L. accessions using RAPD markers

A sum of 48 accessions of physic nut, Jatropha curcas L. were analyzed to determine the genetic diversity and association between geographical origin using RAPD-PCR markers. Eight primers generated a total of 92 fragments with an average of 11.5 amplicons per primer. Polymorphism percentages of J. curcas accessions for Selangor, Kelantan, and Terengganu states were 80.4, 50.0, and 58.7%, respectively, with an average of 63.04%. Jaccard’s genetic similarity co-efficient indicated the high level of genetic variation among the accessions which ranged between 0.06 and 0.81. According to UPGMA dendrogram, 48 J. curcas accessions were grouped into four major clusters at coefficient level 0.3 and accessions from same and near states or regions were found to be grouped together according to their geographical origin. Coefficient of genetic differentiation (G_st) value of J. curcas revealed that it is an outcrossing species.