首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
BackgroundGenetic diversity and genetic variation of 10 populations and subpopulations of Magnolia wufengensis, a new and endangered endemic species, were examined by inter simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) molecular markers. Compared with other endangered endemic Magnolia taxa, M. wufengensis holds a relatively high level of genetic variation.ResultTotal genetic diversity was found to be 87.7% for ISSR and 88.0% for SRAP markers. For polymorphic loci (P), the effective mean number of alleles (Ae) was 1.414 for ISSR markers and 1.458 for SRAP markers, while the mean expected heterozygosity (H) was 0.256 using ISSR and 0.291 for SRAP markers. Within-population variation was estimated for P as 74.9% using ISSR and 74.6% with SRAP markers; the number of alleles Ae was 1.379 with ISSR and 1.397 for SRAP and H 0.235 with ISSR and 0.247 for SRAP markers.ConclusionThe analysis of molecular variation of both ISSR and SRAP marker systems indicated that most genetic variation is within populations, with values of 90.64% and 82.92% respectively. Mantel tests indicated a moderate association between the two marker systems and a low correlation between genetic and geographic distances. High levels of genetic diversity and low levels of population divergence suggest that genetic drift is not currently of great concern for this species. Severe habitat loss and fragmentation, predominantly ascribed to anthropogenic pressures, caused in-situ developing restriction of this species. Action for conserving this rare species for its long-term survival should be taken immediately.  相似文献   

2.
BackgroundPenthorum chinense Pursh (P. chinense) is a well-known traditional Chinese medicine (TCM) plant, which has long been used for the prevention and treatment of hepatic diseases. This study aimed to genetically characterize the varieties of P. chinense from different geographic localities of China by random amplification of polymorphic DNA (RAPD)-PCR technique and verified with inter-simple sequence repeat (ISSR) markers.ResultsThe P. chinense samples were collected from nine different geographic localities. Previously improved RAPD and ISSR markers were utilized for genetic analysis using DNA amplification. The genetic relationship dendrogram was obtained by conducting cluster analysis to the similarity coefficient of improved RAPD and ISSR markers. Improved RAPD yielded 185 scorable amplified products, of which 68.6% of the bands were polymorphic, with an average amplification of 9.25 bands per primer. The ISSR markers revealed 156 alleles with 7.8 bands per primers, where 59.7% bands were polymorphic. Furthermore, the similarity coefficient ranges of RAPD and ISSR markers were 0.71–0.91 and 0.66–0.89, respectively.ConclusionsThis study indicated that improved RAPD and ISSR methods are useful tools for evaluating the genetic diversity and characterizing P. chinense. Our findings can provide the theoretical basis for cultivar identification, standardization, and molecular-assisted breeding of P. chinense for medicinal use.  相似文献   

3.
BackgroundYacon (Smallanthus sonchifolius) is a root crop native to the Andean region. Low sexual reproductive capacity is a major constraint facing the genetic breeding of this crop. Biotechnological techniques offer alternative ways to widen genetic variability. We investigated somaclonal variation in regenerants of yacon derived from in vitro somatic embryogenesis using simple sequence repeat (ISSR) analysis and flow cytometry.ResultsTwenty tested ISSR primers provided a total of 7848 bands in 60 in vitro regenerants and control plant. The number of bands for each primer varied from 3 to 10, and an average of 6.95 bands was obtained per ISSR primer. Eight primers were polymorphic and generated 10 polymorphic bands with 7.19% mean polymorphism. ISSR analysis revealed genetic variability in 6 plants under study. These regenerants had Jaccard's distances 0.104, 0.020, 0.040, 0.106, 0.163 and 0.040. Flow cytometric analysis did not reveal changes of relative nuclear DNA content in regenerants suggesting that the plants obtained via somatic embryogenesis had maintained stable octoploid levels.ConclusionsOur findings show that indirect somatic embryogenesis could be used in yacon improvement to widen genetic variability, especially when low sexual reproductive capacity hinders classical ways of breeding.  相似文献   

4.
BackgroundCultivation of algae for conversion to biofuels has gained global interest. Outdoor raceway cultivation is preferred because of its lower capital and operating costs. A major disadvantage of outdoor cultivation is susceptibility of algal crops to attack by predatory rotifers. In order to quantify the impact of rotifer attack on different species of algae, we evaluated the growth of eleven microalgal species over a 21-d period after being infected by the predatory rotifer Brachionus rubens.ResultsOf the eleven species, Chlorella sorokiniana was the most susceptible with rapid decline in algal growth concomitant with increase in rotifer population growth (3.82/d). In contrast, Synechococcus elongatus and Scenedesmus dimorphus were both resistant to the rotifer and suppressed rotifer growth (-0.06/d). An index of algal species susceptibility to be consumed by the rotifer was generated with C. sorokiniana as the baseline (index = 1.000) indicating most susceptible among species tested. Other species' susceptibilities are indicated in parenthesis as follows: Monoraphidium spp. (0.997), Chlamydomonas globosa (0.827), Botryococcus braunii (0.740), Chlorella minutissima (0.570), Chlamydomonas augustae (0.530), Chlamydomonas yellowstonensis (0.500), Scenedesmus bijuga (0.420), and Haematococcus pluvialis (0.360). Two species, namely, S. dimorphus and S. elongatus were unique in that they exhibited an ability to suppress the growth of the rotifer as indicated by the decline in rotifer populations in their presence.ConclusionsVariations in susceptibility of algal species to rotifer predation could be a result of their individual morphology, cell walls structure, or the biochemical composition of individual species.  相似文献   

5.
BackgroundMemecylon species are commonly used in Indian ethnomedical practices. The accurate identification is vital to enhance the drug's efficacy and biosafety. In the present study, PCR based techniques like RAPD, ISSR and DNA barcoding regions, such as 5s, psbA-trnH, rpoC1, ndh and atpF-atpH, were used to authenticate and analyze the diversity of five Memecylon species collected from Western Ghats of India.ResultsPhylogenetic analysis clearly distinguished Memecylon malabaricum from Memecylon wightii and Memecylon umbellatum from Memecylon edule and clades formed are in accordance with morphological keys. In the RAPD and ISSR analyses, 27 accessions representing five Memecylon species were distinctly separated into three different clades. M. malabaricum and M. wightii grouped together and M. umbellatum, M. edule and Memecylon talbotianum grouped in the same clade with high Jaccard dissimilarity coefficient and bootstrap support between each node, indicating that these grouped species are phylogenetically similar.ConclusionData from the present study reveals that chloroplast psbA-trnH region could be used as a potential candidate region for identifying Memecylon species, and ISSR marker system could be used for estimating genetic diversity since it has high percent polymorphism compared to RAPD marker.  相似文献   

6.
BackgroundAt present, species known as camote de cerro (Dioscorea spp.) are found only in the wilderness in Mexico, but their populations are extremely depleted because they are indiscriminately collected, it is urgent to evaluate the conservation status of these plants in order to design conservation genetics programs. In this study, genetic diversity parameters along with cluster analysis based on Jaccard's coefficient were estimated with the objective to assess the efficiency of Random Amplified Polymorphic DNA (RAPD), Inter Simple Sequence Repeat (ISSR), Amplified Fragment Length Polymorphism (AFLP) and Inverse Sequence Tagged Repeat (ISTR) molecular DNA markers in the Dioscorea genus.ResultsThe polymorphic information contents were quite similar for all markers (≈ 0.48). Genetic variation of Dioscorea spp., in terms of average heterozygosity was lower with ISTR (0.36), and higher when other markers were used (RAPD = 0.43; ISSR = 0.45 and AFLP = 0.47).ConclusionThis indicates an important level of genetic differences despite the fact that the plant is asexually propagated. Based on the diversity statistics, any marker tested in present work can be recommended for use in large-scale genetic studies of populations. However, the low correlations among different molecular marker systems show the importance of the complementarity of the information that is generated by different markers for genetic studies involving estimation of polymorphism and relationships.  相似文献   

7.
BackgroundGenetic diversity of sheep in Jordan was investigated using microsatellite markers (MS). Six ovine and bovine MS located on chromosomes 2 and 6 of sheep genome were genotyped on 294 individual from ten geographical regions.ResultsThe number of alleles per locus (A), the expected heterozygosity (He) and observed heterozygosity (Ho) were measured. Overall A, He and Ho were 12.67, 0.820 and 0.684, respectively. On the other hand, genetic distances undoubtedly revealed the expected degree of differentiation among the studied populations. The finding showed closeness of three populations from south (Maan, Showbak and Tafeilah) to each other. Populations from the middle regions of Jordan (Karak, Madaba, Amman, AzZarqa and Mafraq) were found to be in one cluster. Only two populations of the middle region were an exception: AlSalt and Dead Sea. Finally, sheep populations from Irbid were located in separated cluster. It was clear that the studied predefined populations were subdivided from four populations and would be most probably accounted as ancestral populations. These results indicate that number of population is less than the predefined population as ten based on geographical sampling areas.ConclusionsThe possible inference might be that geographical location, genetic migration, similar selection forces, and common ancestor account for population admixture and subdivision of Awassi sheep breed in Jordan. Finally, the present study sheds new light on the molecular and population genetics of Awassi sheep from different regions of Jordan and to utilize the possible findings for future management of genetic conservation under conditions of climate changes and crossbreeding policy.  相似文献   

8.
BackgroundAssessments of genetic diversity are essential for germplasm characterization and exploitation. Molecular markers are valuable tools for exploring genetic variation and identifying germplasm. They play key roles in a Xanthoceras sorbifolia breeding program.ResultsWe analyzed the genetic diversity of populations of this species using 23 simple sequence repeat (SSR) loci and data on kernel oil content. The 11 populations included in the study were distributed across a large geographic range in China. The kernel oil content differed significantly among populations. The SSR marker analysis detected high genetic diversity among the populations. All SSRs were polymorphic, and we identified 80 alleles across the populations. The number of alleles at each locus ranged from two to six, averaging 3.48 per primer pair. The polymorphism information content values ranged from 0.35 to 0.70, averaging 0.51. Expected heterozygosity, observed heterozygosity, and Shannon's information index calculations detected large genetic variations among populations of different provenance. The high average number of alleles per locus and the allelic diversity observed in the set of genotypes analyzed indicated that the genetic base of this species was relatively wide. The statistically significant positive correlation between genetic and geographic distances suggested adaptations to local conditions.ConclusionsMicrosatellite markers can be used to efficiently distinguish X. sorbifolia populations and assess their genetic diversity. The information we have provided will contribute to the conservation and management of this important plant genetic resource.  相似文献   

9.
BackgroundFor the crossbreeding of Auricularia auricula-judae, selecting the appropriated parents in hybridization is very important. However, the classification and diversity analysis of A. auricula-judae has been equivocal, due to the similarity of the fruiting body morphology and its susceptibility to environmental influences. For this purpose, the molecular diversity of 32 A. auricula-judae commercial cultivars in China was analyzed by using the nuclear ribosomal DNA intergenic spacer.ResultsThe complete nuclear rDNA gene complex of A. auricula-judae isolate is 11,210 bp long, and contains the 18S, 5.8S, and 28S rRNA gene as well as the ITS and IGS regions. Based on the sequence data, four more effective primer combinations for the IGS region of A. auricula-judae were designed. Nucleotide sequence variation in the IGS among 32 A. auricula-judae commercial cultivars in China sorted into three strongly supported clades, which is correlated with geographical regions. Most strains originated from the same area were with a narrow genetic basis and could possibly be domesticated from the local wild-type strains.ConclusionThe grouping information obtained in the present work provides significant information for further genetic improvement in A. auricula-judae, and suggested that the IGS region can be used as an excellent tool for identification of genetic variation.  相似文献   

10.
11.
BackgroundProcambarus clarkii produces high-quality, delicious meat that is high in protein, low in fat, and rich in calcium and phosphorus. It has become an important aquatic resource in China. Our objectives are (i) to analyze the level of genetic diversity of P. clarkii populations; (ii) to explore the genetic differentiation (Gst); and (iii) to propose appropriate strategies for the conservation.ResultsIn this study, Shannon's index (I) and Nei's gene diversity index (H) for P. clarkii were high (I = 0.3462 and H = 0.2325 on average and I = 0.6264, H = 0.4377 at the species level) based on the SSR markers. The expected heterozygosity value of 17 microsatellite loci in 25 crayfish populations was 0.9317, the observed heterozygosity value was 0.9121, and the observed number of alleles per locus was 2.000; and the effective number of alleles per locus was 1.8075. Among the P. clarkii populations, the inbreeding coefficient within populations (Fis) was 0.2315, overall inbreeding coefficient (Fit) was 0.4438, genetic differentiation coefficient among populations (Fst) was 0.3145 and gene differentiation (Gst) was 0.4785 based on SSR analyses. The cluster analysis results obtained by unweighted pair-group method with arithmetic mean (UPGMA) analysis, principal coordinate analysis (PCoA) and STRUCTURE analysis were similar. A mantel test showed that the isolation-by-distance pattern was not significant.ConclusionsThe high Gst among P. clarkii populations is attributed to genetic drift and geographic isolation. The results indicated that more P. clarkii populations should be collected when formulating conservation and aquaculture strategies.How to citeLiu F, Qu Y-K, Geng C, et al. Analysis of the population structure and genetic diversity of the red swamp crayfish (Procambarus clarkii) in China using SSR markers. Electron J Biotechnol 2020;47. https://doi.org/10.1016/j.ejbt.2020.06.007.  相似文献   

12.
BackgroundPomegranate (Punica granatum L.), one of the most important tropical fruits in Azad Jammu and Kashmir regions of Pakistan, is highly valued for its nutrition and medicinal purposes. Although pomegranate is native to this region, the genetic diversity among wild pomegranate accessions is currently unknown. Such information would be vital for germplasm conservation and breeding efforts. In the current study, genetic diversity among forty-eight wild pomegranate accessions collected from different agro-ecological zones of Azad Jammu and Kashmir was assessed using 41 simple sequence repeat (SSR) markers.ResultsThe markers revealed 303 alleles averaging 7.39 alleles per marker. Polymorphic information content ranged from 0.12 (PGCT093B) to 0.88 (Pom006), with a mean of 0.54. The average genetic distance (GD) across all genotypes was 0.52, and was lowest between Chattar Class and Thorar genotypes (GD = 0.27), but highest between Khun Bandway and Akhor Ban (GD = 0.74). A neighbor-joining dendrogram separated the genotypes into three major clusters, with further sub-clustering within each cluster.ConclusionsOverall, the results presented here show significant genetic diversity among wild pomegranate accessions in Azad Jammu and Kashmir region of Pakistan. These accessions present a valuable genetic resource to breeding and cultivar improvement programs within the region.How to cite: Aziz S, Firdous S, Rahman H, et al. Genetic diversity among wild pomegranate (Punica granatum) in Azad Jammu and Kashmir region of Pakistan. Electron J Biotechnol 2020;46. https://doi.org/10.1016/j.ejbt.2020.06.002.  相似文献   

13.
BackgroundAgave tequilana has a great economic importance in Mexico in order to produce alcoholic beverages and bioenergy. However, in this species the structure and organization of the rDNAs in the genome are limited, and it represents an obstacle both in their genetic research and improvement as well. rDNA copy number variations per eukaryotic genome have been considered as a source of genetic rearrangements. In this study, the copy number of 18S and 5S rDNAs in the A. tequilana genome was estimated, and an absolute quantitative qPCR assay and genome size was used. In addition, an association between the rDNAs copy number and physical mapping was performed to confirm our results.ResultsThe analysis were successfully applied to determine copy number of 18S and 5S rDNAs in A. tequilana genome, showing high reproducibility with coefficient of variation (CV) values of 0.014–0.0129%, respectively. A variation of 51 times in the copy number the 18s regarding 5s rDNA was found, thus contributing to genome size of 1.47 and 8.38 × 10-3%, respectively. Similarly, data show a linear relationship (R [2] = 0.992) between rDNA copy number and the detected signals for each of the loci by FISH. The comparison of the rDNA copy number of agave showed differential relationship with other organisms and it may be due to evolutionary ecology.ConclusionsResults show that the proposed method a) can correctly detect the rDNA copy number, b) could be used as species-specific markers and c) might help in understanding the genetic diversity, genome organization and evolution of this species.  相似文献   

14.
BackgroundEnteric red mouth disease and Saprolegniasis, which are caused by the bacteria Yersinia ruckeri and the oomycete Saprolegnia parasitica, respectively, are important illnesses that affect salmonid farming. Sanitary problems in farms are addressed by the prevention of disease outbreaks or by the treatment of diseases with chemicals. Environmental and governmental restrictions, toxicity and high treatment costs limit the use of drugs. Marine organisms, such as algae, sponges and corals, have developed an antimicrobial defense strategy based on the production of bioactive metabolites. Among these organisms, seaweeds offer a particularly rich source of potential new drugs. Hence, many pharmacologically active substances have been isolated from seaweeds. In the Ceramium genus, Ceramium rubrum has been emphasized by several authors for its antimicrobial properties. Based on this background, the present study focused on the antimicrobial activity of a lipophilic extract of C. rubrum on Y. ruckeri and S. parasitica.ResultsThe alga, collected from the Pacific coast of Chile, underwent an ethanol extraction, and the concentrated extract was partitioned between water and dichloromethane. From the dichloromethane extract, fatty acids, fatty acid esters, one hydrocarbon and phytol were identified by Gas Chromatography–Mass Spectrometry (GC/MS) analysis. The antimicrobial study showed that the whole extract was more active than the individual components, which suggests a strong synergistic effect among the components.ConclusionsThese results may constitute a basis for promising future applied research that could investigate the use of C. rubrum seaweed as a source of antimicrobial compounds against fish pathogens.  相似文献   

15.
BackgroundFragrance is one of the most important quality traits in rice, and the phenotype is attributed to the loss-of-function betaine aldehyde dehydrogenase (BADH2) gene. At least 12 allelic variations of BADH2 have been identified, and some of these have been applied to rice fragrance breeding using traditional molecular markers and Sanger sequencing techniques. However, these traditional methods have several limitations, such as being very expensive, imprecise, inefficient, and having security issues. Thus, a new molecular marker technology must be developed to improve rice fragrance breeding.ResultsIn this study, more than 95% of the cultivated fragrant rice varieties belonged to a 7-bp deletion in exon 2 (badh2-E2) or an 8-bp deletion and 3-bp variation in exon 7 (badh2-E7). Both allelic variations resulted in the loss of function of the badh2 gene. We developed two novel SNP molecular markers, SNP_badh2-E2 and SNP_badh2-E7, related to the alleles. Their genotype and phenotype were highly cosegregated in the natural variation of rice accessions, with 160 of the 164 fragrant rice varieties detected with the two markers. These markers cosegregated with the fragrance phenotype in the F2 population.ConclusionsTwo functional SNP molecular markers of badh2-E2 and badh2-E7 allelic variations were developed. These functional SNP molecular markers can be used for genotype and genetic improvement of rice fragrance through marker-assisted selection and will significantly improve the efficiency of fragrant rice breeding and promote commercial molecular breeding of rice in the future.How to cite: Li W, Zeng X, Li S, et al. Development and application of two novel functional molecular markers of BADH2 in rice. Electron J Biotechnol 2020;46. https://doi.org/10.1016/j.ejbt.2020.04.004.  相似文献   

16.
BackgroundThe aim of the present study was to assess the genetic diversity of Pantaneiro sheep, using microsatellite markers, in order to assist maintenance and management plans, enhance mating systems and reduce the inbreeding rate. A total of 127 animals were genotyped at eight microsatellite loci. They belonged to populations from the Experimental Farm of the Universidade Federal da Grande Dourados (UFGD) (Dourados/MS/Brazil) and Embrapa Pantanal (Corumbá/MS/Brazil).ResultsThe population of Pantaneiro sheep from the UFGD exhibited a high mean number of alleles (11.13) and allelic richness (10.66). The polymorphic information content was highly informative in the locus studied, resulting in a mean value of 0.71. Observed heterozygosity was lower than expected for all molecular markers assessed. The analysis of molecular variance showed a differentiation rate of 5.2% between populations.ConclusionsThe results of the statistical parameters indicated that populations of Pantaneiro sheep require special attention on herd management, and it's further necessary to implement breeder exchange programs in order to preserve the genetic variability of these populations. Furthermore, the maintenance of those populations in their typical habitats is rather required to allow different responses from the herds to the interactions between genotype and environment.  相似文献   

17.
BackgroundMeretrix petechialis is one of the commercially important marine bivalves. In this study, we selected six highly polymorphic EST-derived microsatellite markers to assess the genetic diversity and population differentiation on nine wild populations of Meretrix petechialis.ResultsThe number of alleles detected per locus ranged from 4 to 30 (mean NA = 27.5) with a total of 165 alleles. The mean value of observed and expected heterozygosities varied from 0.717 to 0.861 and from 0.797 to 0.856, respectively. Meanwhile, the result of Neighbor-joining and overall FST = 0.214 (P < 0.01) reveled that M. petechialis populations from GX are the farthest populations, a certain degree of genetic variation among individuals in each population and the genetic differentiation is significant.ConclusionsGX population has high genetic diversity among individual, and there are certain differences in genetic characteristics among different populations. This study will provide a basis for the domestication and cultivation of genetic diversity of M. petechialis population and the protection of clam germplasm resources.How to citeXu Q, Zheng J, Yan X, et al. Genetic diversity and differentiation of nine populations of the hard clam (Meretrix petechialis) assessed by EST-derived microsatellites. Electron J Biotechnol 2020;48. https://doi.org/10.1016/j.ejbt.2020.09.003  相似文献   

18.
19.
BackgroundAvailability of related rice species is critical for rice breeding and improvement. Two distinct species of domesticated rice exist in the genus Oryza: Oryza sativa (Asian rice) and Oryza glaberrima (African rice). New rice for Africa (NERICA) is derived from interspecific crosses between these two species. Molecular profiling of these germplasms is important for both genetics and breeding studies. We used 30 polymorphic SSR markers to assess the genetic diversity and molecular fingerprints of 53 rice genotypes of O. sativa, O. glaberrima, and NERICA.ResultsIn total, 180 alleles were detected. Average polymorphism information content and Shannon's information index were 0.638 and 1.390, respectively. Population structure and neighbor-joining phylogenetic tree revealed that 53 genotypes grouped into three distinct subpopulations conforming to the original three groups, except three varieties (IR66417, WAB450-4, MZCD74), and that NERICA showed a smaller genetic distance from O. sativa genotypes (0.774) than from O. glaberrima genotypes (0.889). A molecular fingerprint map of the 53 accessions was constructed with a novel encoding method based on the SSR polymorphic alleles. Ten specific SSR markers displayed different allelic profiles between the O. glaberrima and O. sativa genotypes.ConclusionsGenetic diversity studies revealed that 50 rice types were clustered into different subpopulations whereas three genotypes were admixtures. Molecular fingerprinting and 10 specific markers were obtained to identify the 53 rice genotypes. These results can facilitate the potential utilization of sibling species in rice breeding and molecular classification of O. sativa and O. glaberrima germplasms.  相似文献   

20.
BackgroundArsenic contamination in the ground water of rural India is a recurrent problem and decontamination is mostly based on the chemical or physical treatments until now. Microbial bioremediation is eco-friendly, cheap, time-efficient and does not produce any toxic by-products.ResultIn the present study, a high arsenic tolerant bacteria Brevundimonas aurantiaca PFAB1 was isolated from Panifala hot spring located in West Bengal, India. Previously Panifala was also reported to be an arsenic-rich hot spring. B. aurantiaca PFAB1 exhibited both positive arsenic reductase and arsenite oxidase activity. It was tolerant to arsenite up to 90 mM and arsenate up to 310 mM. Electron microscopy has proved significant changes in cellular micromorphology and stalk appearance under the presence of arsenic in growth medium. Bioaccumulation of arsenic in As (III) treated cells were 0.01% of the total cell weight, while 0.43% in case of As (V) treatment.ConclusionsAll experimental lines of evidence prove the uptake/accumulation of arsenic within the bacterial cell. All these features will help in the exploitation of B. aurantiaca PFAB1 as a potent biological weapon to fight arsenic toxicity in the near future.How to cite: Banerjee A, Sarkar S, Gorai S, et al. High arsenic tolerance in Brevundimonas aurantiaca PFAB1 from an arsenic-rich Indian hot spring. Electron J Biotechnol 2021:52. https://doi.org/10.1016/j.ejbt.2021.05.006  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号