scholarly journals Genetic structure and gene flow of Eugenia dysenterica natural populations

2005 ◽  
Vol 40 (10) ◽  
pp. 975-980 ◽  
Author(s):  
Maria Imaculada Zucchi ◽  
José Baldin Pinheiro ◽  
Lázaro José Chaves ◽  
Alexandre Siqueira Guedes Coelho ◽  
Mansuêmia Alves Couto ◽  
...  

This study was carried out to assess the genetic variability of ten "cagaita" tree (Eugenia dysenterica) populations in Southeastern Goiás. Fifty-four randomly amplified polymorphic DNA (RAPD) loci were used to characterize the population genetic variability, using the analysis of molecular variance (AMOVA). A phiST value of 0.2703 was obtained, showing that 27.03% and 72.97% of the genetic variability is present among and within populations, respectively. The Pearson correlation coefficient (r) among the genetic distances matrix (1 - Jaccard similarity index) and the geographic distances were estimated, and a strong positive correlation was detected. Results suggest that these populations are differentiating through a stochastic process, with restricted and geographic distribution dependent gene flow.

Genome ◽  
1997 ◽  
Vol 40 (5) ◽  
pp. 600-606 ◽  
Author(s):  
Ines Swoboda ◽  
Prem L. Bhalla

The use of randomly amplified polymorphic DNA (RAPD) to study genetic variability in Scaevola (family Goodeniaceae), a native Australian species used in ornamental horticulture, is demonstrated. Plants of the genus Scaevola are commonly known as "fan flowers," due to the fan-like shape of the flowers. Nineteen accessions of Scaevola (12 cultivated and 7 wild) were studied using 20 random decamer arbitrary primers. Eight primers gave a distinct reproducible amplification profile of 90 scorable polymorphic fragments, enabling the differentiation of the Scaevola accessions. RAPD amplification of genomic DNA revealed a high genetic variability among the different species of Scaevola studied. Molecular markers were used to calculate the similarity coefficients, which were then used for determining genetic distances between each of the accessions. Based on genetic distances, a dendrogram was constructed. Though the dendrogram is in general agreement with the taxonomy, it also highlights discrepancies in the classification. The RAPD data showed that Scaevola aemula (series Pogogynae) is closer to Scaevola glandulifera of series Globuliferae than to the rest of members of series Pogogynae. In addition, the RAPD banding pattern of white flower S. aemula, one of the commercial cultivars, was identical to that of Scaevola albida, indicating their genetic similarity. Our study showed that there is a large genetic distance between commercial cultivars of Scaevola (Purple Fanfare, Pink Perfection, and Mauve Cluster), indicating considerable genetic variation among them. The use of RAPDs in intra- and inter-specific breeding of Scaevola is also explored.Key words: Scaevola, Australian native, RAPD, genetic distance, genetic variability.


2018 ◽  
Vol 15 (4) ◽  
pp. 381-386
Author(s):  
Baghdad Science Journal

Methicillin resistant Staphylococcus aureus (MRSA) is one of the principal nosocomial causative agents. This bacterium has the capability to resist wide range of antibiotics and it is responsible for many diseases like skin, nose and wounds infection. In this study, randomly amplified polymorphic DNA (RAPD)-PCR was applied with ten random primers to examine the molecular diversity among methicillin resistant Staphylococcus aureus (MRSA) isolates in the hospitals and to investigate the genetic distance between them. 90 Isolates were collected from clinical specimens from Iraqi hospitals for a total of 90 isolates. Only 10 strains (11.11%) were found to be MRSA. From these 10 primers, only 9 gave clear amplification products. 91 fragment lines were generated from these primers across all isolates with an average of 10 fragment lines per primer. Of these, 90 (99%) were polymorphic. The size of the amplified bands ranged between 145-2109 bp. The polymorphism percentage for all primers was 100% except OP-X17 primer which gave 86% polymorphism. The genetic distances revealed from Jaccard similarity index was calculated for the 90 RAPD polymorphic fragment lines. The highest genetic distance value 0.959 was between isolate number (1) and (5) and between isolate number (3) and (10), while the lowest genetic distance value 0.218 was between isolate number (6) and (7). This study shows that RAPD-PCR technique assayed with nine primers can be successfully applied to reveal the genetic distances among methicillin resistant Staphylococcus aureus (MRSA) isolates from different hospitals.


2021 ◽  
Vol 63 (1-2) ◽  
pp. 171-193
Author(s):  
S. Pandey ◽  
A. Alam

Genetic relationships among 24 genotypes of Hyophila involuta collected from five different natural populations of Mount Abu (Rajasthan) is analysed using RAPD and SSR markers. Based on efficiency parameters calculated for each marker system such as polymorphic information content (RAPD = 0.34; SSR = 0.66), marker index (RAPD = 2.78; SSR = 2.62) and resolving power (RAPD = 8.13; SSR = 2.23), the RAPD marker system shows higher values for some indices but microsatellites are more accurately reproducible than RAPD. Moreover, in case of the SSR, the average number of alleles was almost twice compared to RAPD. Mean coefficient of genetic differentiation between populations with RAPD was Gst = 0.269, while with SSR marker was Fst = 0.224. The UPGMA cluster analysis assembled genotypes into two main clusters with diverse levels of sub-clustering within the clusters. Also, the Mantel test showed no significant correlation between geographical and genetic distances. The observed moderately high genetic variability can be explained by efficient spore dispersal. Other factors such as reproductive mode, somatic mutation, continuous propagule recruitment and high degree of intermingling have great impact on the level of genetic variability in moss populations.


2000 ◽  
Vol 90 (8) ◽  
pp. 901-908 ◽  
Author(s):  
S. Salamati ◽  
J. Zhan ◽  
J. J. Burdon ◽  
B. A. McDonald

Restriction fragment length polymorphism (RFLP) markers were used to compare the genetic structure of field populations of Rhynchosporium secalis from barley. A total of 543 isolates representing 8 field populations were sampled from Australia, California, Finland, and Norway. Gene and genotype diversity were high in all populations. Nei's average gene diversity across seven RFLP loci was 0.513. Hierarchical gene diversity analysis showed that 9% of the total genetic variability was distributed among continents, 4% was distributed among fields within continents, and 13% was distributed among collection stations within a field. The majority (74%) of genetic variability was distributed within collection areas of approximately 1 m2 within fields. Gene flow appears to be significant on a regional scale but more restricted among continents. Allele frequencies were significantly different at several RFLP loci. Genetic distances were small among populations within regions and large between regions. Pairwise comparisons of genotype diversity in the populations revealed significant differences among populations that were related mainly to differences in sampling strategies. Isolates from Norway and Finland showed a lower copy hybridization pattern with probe pRS26. This probe functioned as a fingerprint probe for the California and Australian isolates. Seven out of the eight populations studied were at gametic equilibrium for RFLP loci, suggesting that R. secalis populations in Norway, Finland, and Australia undergo regular recombination, although a teleomorph has not yet been recognized.


2020 ◽  
Vol 36 ◽  
Author(s):  
Ronaldo Rodrigues Coimbra ◽  
Danielle Pereira Dos Santos ◽  
Wagner de Melo Ferreira ◽  
Waldesse Piragé de Oliveira Junior ◽  
Elainy Cristina Alves Martins Oliveira

The objective of the current study was to measure the genetic variability of natural populations of Hancornia speciosa using RAPD type molecular markers to assay variation in existing sampled genotypes, using morphological variables, and so assess germplasm bank composition. Morphological and chemical characteristics H. speciosa fruits and seeds were evaluated using descriptive statistics and principal components analysis. Cluster analyzes was conducted using Jaccard's similarity index, via the UPGMA hierarchical agglomerative method. Phenotypic variability was found in the two studied populations. However, variability was higher in the São Judas population, where the variables: pulp yield and soluble solids content were higher than those in the Canaã population. High genetic variability was found in both study populations, and between- and within-population morphological and genetic variation was present in the studied populations. The nine primers generated 70 bands, of which 68 were polymorphic, with the primers A-08 and C-04 generating the highest number of polymorphic bands. The two populations differ principally in the pulp ratio and the proportion of total solids in the pulp (°Brix). RAPD markers used gave acceptable results and, to initiate the Federal University of Tocantins Active Mangaba Germplasm Bank, seven genotypes were sampled from the Canaã population and five from the São Judas Tadeu population.


2010 ◽  
Vol 10 (3) ◽  
pp. 211-217 ◽  
Author(s):  
Michelly de Cristo Araújo ◽  
Doriane Picanço Rodrigues ◽  
Spartaco Astolfi Filho ◽  
Charles Roland Clement

Peach palm is a native Amazonian fruit species with broad genetic diversity in its wild and domesticated populations. This study completed the molecular characterization and genetic analysis of the accessions in the Peach Palm genebank, Brazil, using RAPD markers. Eight primers generated 132 markers, of which 128 were polymorphic. Average heterozigosity was 0.35, with 95.5% polymorphism. The genetic variability within the landraces (H S) was 0.32, while genetic divergence (G ST) was 0.09 among the four well-represented landraces. The average gene flow was 5.0, with high gene flow between the Solimões and Pampa Hermosa (Nm=10.07), and between the Putumayo and Solimões (Nm=10.73) landraces, all western landraces. The dendrograms of the Nei's and Rogers' genetic distances of the well-represented landraces presented similar groupings to previous analyses, with the Solimões, Putumayo and Pampa Hermosa landraces grouped together in western Amazonia, and distant from the Pará landrace in central and eastern Amazonia.


Author(s):  
Giulia Seghezzo ◽  
Yvonne Van Hoecke ◽  
Laura James ◽  
Donna Davoren ◽  
Elizabeth Williamson ◽  
...  

Abstract Background The Preclinical Alzheimer Cognitive Composite (PACC) is a composite score which can detect the first signs of cognitive impairment, which can be of importance for research and clinical practice. It is designed to be administered in person; however, in-person assessments are costly, and are difficult during the current COVID-19 pandemic. Objective To assess the feasibility of performing the PACC assessment with videoconferencing, and to compare the validity of this remote PACC with the in-person PACC obtained previously. Methods Participants from the HEalth and Ageing Data IN the Game of football (HEADING) Study who had already undergone an in-person assessment were re-contacted and re-assessed remotely. The correlation between the two PACC scores was estimated. The difference between the two PACC scores was calculated and used in multiple linear regression to assess which variables were associated with a difference in PACC scores. Findings Of the 43 participants who were invited to this external study, 28 were re-assessed. The median duration in days between the in-person and the remote assessments was 236.5 days (7.9 months) (IQR 62.5). There was a strong positive correlation between the two assessments for the PACC score, with a Pearson correlation coefficient of 0·82 (95% CI 0·66, 0·98). The multiple linear regression found that the only predictor of the PACC difference was the time between assessments. Interpretation This study provides evidence on the feasibility of performing cognitive tests online, with the PACC tests being successfully administered through videoconferencing. This is relevant, especially during times when face-to-face assessments cannot be performed.


2004 ◽  
Vol 64 (2) ◽  
pp. 327-336 ◽  
Author(s):  
J. M. M. Santos ◽  
J. F. Maia ◽  
W. P. Tadei

Populations of Anopheles triannulatus from Macapá (AP), Aripuanã (MT), Ji-Paraná (RO), and Manaus-Janauari Lake (AM) were studied using 16 enzymatic loci. The results of the isozyme analysis showed that the population of Macapá presented higher polymorphism (56.3%). The lowest variability was observed in the population of Manaus (p = 25.0; Ho = 0.077 ± 0.046). The results of Wright's F statistics showed unbalance due to excess of homozygotes (Fis > Fst), denoting a certain intrapopulational differentiation. Although the populations are genetically very close (D = 0.003 - 0.052), the dendrogram separates the populations in two groups: Macapá separated from that of Manaus, Ji-Paraná, and Aripuanã. This result may suggest a reduction in the genic flow, which possibly had some influence in the substructuration of the populations.


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