scholarly journals Clonal Population Structure of Pseudomonas stutzeri, a Species with Exceptional Genetic Diversity

2001 ◽  
Vol 183 (2) ◽  
pp. 736-744 ◽  
Author(s):  
Núria Rius ◽  
M. Carme Fusté ◽  
Caterina Guasp ◽  
Jorge Lalucat ◽  
José G. Lorén

ABSTRACT Genetic diversity and genetic relationships among 42Pseudomonas stutzeri strains belonging to several genomovars and isolated from different sources were investigated in an examination of 20 metabolic enzymes by multilocus enzyme electrophoresis analysis. Forty-two distinct allele profiles were identified, indicating that all multilocus genotypes were represented by a single strain. All 20 loci were exceptionally polymorphic, with an average of 15.9 alleles per locus. To the best of our knowledge, thisP. stutzeri sample exhibited the highest mean genetic diversity (H = 0.876) found to date in all bacterial species studied by multilocus enzyme electrophoresis. A high frequency of occurrence of null alleles was identified. The index of association (IA ) for the P. stutzeri strains analyzed was 1.10. The IA values were always significantly different from zero for all subgroups studied, including clinical and environmental isolates and strains classified as genomovar 1. These results suggest that the population structure of P. stutzeri is strongly clonal, indicating that there is no significant level of assortative recombination that might destroy linkage disequilibrium.

Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2891-2900 ◽  
Author(s):  
Marco Scortichini ◽  
Emanuela Natalini ◽  
Luca Angelucci

To assess the genetic diversity and genetic relationships of Pseudomonas avellanae, the causative agent of hazelnut decline, a total of 102 strains, obtained from central Italy (provinces of Viterbo and Rome) and northern Greece, were studied using multilocus enzyme electrophoresis (MLEE). Their allelic variation in 10 loci was determined. All loci were polymorphic and 53 electrophoretic types (ETs) were identified from the total sample. The mean genetic diversity (H) was 0·65 and this value ranged from 0·37 for the least polymorphic to 0·82 for the most polymorphic locus. The dendrogram originated from MLEE data indicated two main groups of ETs, A and B. The groups do not appear to be correlated to the geographic origin of the strains, although all the ETs from northern Greece clustered into subgroup B1. Pseudomonas syringae pv. actinidiae and P. syringae pv. theae, included in the analysis as outgroups, clustered apart. The index of association (I A) for P. avellanae was 0·90. The I A values were always significantly different from zero for the population subsets studied and no epidemic structure was found. These results would indicate that the population structure of P. avellanae is clonal either in northern Greece or in central Italy. The recent outbreaks of the bacterium in new areas of hazelnut cultivation would explain the current clonal structure that is persisting over decades.


2004 ◽  
Vol 70 (12) ◽  
pp. 7210-7219 ◽  
Author(s):  
Blanca de las Rivas ◽  
Ángela Marcobal ◽  
Rosario Muñoz

ABSTRACT Oenococcus oeni is the organism of choice for promoting malolactic fermentation in wine. The population biology of O. oeni is poorly understood and remains unclear. For a better understanding of the mode of genetic variation within this species, we investigated by using multilocus sequence typing (MLST) with the gyrB, pgm, ddl, recP, and mleA genes the genetic diversity and genetic relationships among 18 O. oeni strains isolated in various years from wines of the United States, France, Germany, Spain, and Italy. These strains have also been characterized by ribotyping and restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified 16S-23S rRNA gene intergenic spacer region (ISR). Ribotyping grouped the strains into two groups; however, the RFLP analysis of the ISRs showed no differences in the strains analyzed. In contrast, MLST in oenococci had a good discriminatory ability, and we have found a higher genetic diversity than indicated by ribotyping analysis. All sequence types were represented by a single strain, and all the strains could be distinguished from each other because they had unique combinations of alleles. Strains assumed to be identical showed the same sequence type. Phylogenetic analyses indicated a panmictic population structure in O. oeni. Sequences were analyzed for evidence of recombination by split decomposition analysis and analysis of clustered polymorphisms. All results indicated that recombination plays a major role in creating the genetic heterogeneity of O. oeni. A low standardized index of association value indicated that the O. oeni genes analyzed are close to linkage equilibrium. This study constitutes the first step in the development of an MLST method for O. oeni and the first example of the application of MLST to a nonpathogenic food production bacteria.


1996 ◽  
Vol 116 (1) ◽  
pp. 41-49 ◽  
Author(s):  
M. M. Feizabadi ◽  
I. D. Robertson ◽  
D. V. Cousins ◽  
D. Dawson ◽  
W. Chew ◽  
...  

SummaryGenetic relationships amongst 115 mainly Australian isolates ofMycobacterium aviumwere assessed using multilocus enzyme electrophoresis (MEE). The isolates were divided into 58 electrophoretic types (ETs), with a mean genetic diversity of 0·29. Isolates from humans were closely related to but distinct from those cultured from birds, whilst some porcine isolates belonged to the same ETs as certain human isolates. Pulsed field gel electrophoresis (PFGE) was used to differentiate related isolates, and those from birds and some from other animals, including pigs, were distinguished from the human isolates. The results of MEE and PFGE suggested that certain strains ofM. aviummay be transmitted between birds and pigs, but there was no clear evidence of transmission to humans. The serovar of theM. aviumisolates was not obviously related to their ET assignment or their PFGE type.


1992 ◽  
Vol 108 (1) ◽  
pp. 31-38 ◽  
Author(s):  
C. L. Poh ◽  
J. C. Ocampo ◽  
G. K. Loh

Multilocus enzyme electrophoretic analysis was employed to assess the genetic relatedness ofNeisseria gonorrhoeae. Based on the diversity of electromorphs at 9 enzyme loci, 16 electrophoretic types (ETs) were estabilished amongst the 65 isolates. The average number of alleles per enzyme locus was 1·7 and the mean genetic diversity per locus was 0·212. The majority of isolates belonged to either ET1 (32·3%) or ET2 (16·9%). No specific correlation of ETs was seen with serovars as the major types, ETs 1 and 2, were found distributed amongst the various serovars. Major serovars such as Bacjk (IB-1/2) and Bajk (IB-3/6) were each represented by 6 or 8 ETs respectively. Analysis of the genetic relationships of ETs to each other showed some clustering of subgroups that were more closely related than others.


2002 ◽  
Vol 184 (5) ◽  
pp. 1304-1313 ◽  
Author(s):  
M. Farfán ◽  
D. Miñana-Galbis ◽  
M. C. Fusté ◽  
J. G. Lorén

ABSTRACT Comparative analysis of gene fragments of six housekeeping loci, distributed around the two chromosomes of Vibrio cholerae, has been carried out for a collection of 29 V. cholerae O139 Bengal strains isolated from India during the first epidemic period (1992 to 1993). A toxigenic O1 ElTor strain from the seventh pandemic and an environmental non-O1/non-O139 strain were also included in this study. All loci studied were polymorphic, with a small number of polymorphic sites in the sequenced fragments. The genetic diversity determined for our O139 population is concordant with a previous multilocus enzyme electrophoresis study in which we analyzed the same V. cholerae O139 strains. In both studies we have found a higher genetic diversity than reported previously in other molecular studies. The results of the present work showed that O139 strains clustered in several lineages of the dendrogram generated from the matrix of allelic mismatches between the different genotypes, a finding which does not support the hypothesis previously reported that the O139 serogroup is a unique clone. The statistical analysis performed in the V. cholerae O139 isolates suggested a clonal population structure. Moreover, the application of the Sawyer's test and split decomposition to detect intragenic recombination in the sequenced gene fragments did not indicate the existence of recombination in our O139 population.


2021 ◽  
Author(s):  
Varun Hiremath ◽  
Kanwar Pal Singh ◽  
Neelu Jain ◽  
Kishan Swaroop ◽  
Pradeep Kumar Jain ◽  
...  

Abstract Genetic diversity and structure analysis using molecular markers is necessary for efficient utilization and sustainable management of gladiolus germplasm. Genetic analysis of gladiolus germplasm using SSR markers is largely missing due to scarce genomic information. In the present investigation, we report 66.66% cross transferability of Gladiolus palustris SSRs whereas 48% of Iris EST-SSRs were cross transferable across the gladiolus genotypes used in the study. A total of 17 highly polymorphic SSRs revealed a total 58 polymorphic loci ranging from two to six in each locus with an average of 3.41 alleles per marker. PIC values ranged from 0.11 to 0.71 with an average value of 0.48. Four SSRs were selectively neutral based on Ewens-Watterson test. Analysis of genetic structure of 84 gladiolus genotypes divided whole germplasm into two subpopulations. 35 genotypes were assigned to subpopulation 1 whereas 37 to subpopulation 2 and rest of the genotypes recorded as admixture. Analysis of molecular variance indicated maximum variance (53.59%) among individuals within subpopulations whereas 36.55% of variation observed among individuals within total population. Least variation (9.86%) was noticed between two subpopulations. Moderate (FST = 0.10) genetic differentiation of two subpopulations was observed. Grouping pattern of population structure was consistent with UPGMA dendrogram based on simple matching dissimilarity coefficient (ranged from 01.6 to 0.89) and PCoA. Genetic relationships assessed among the genotypes of respective clusters assist the breeders in selecting desirable parents for crossing. SSR markers from present study can be utilized for cultivar identification, conservation and sustainable utilization of gladiolus genotypes for crop improvement.


2020 ◽  
Author(s):  
Brenda G. Díaz ◽  
Maria I. Zucchi ◽  
Alessandro. Alves-Pereira ◽  
Caléo P. de Almeida ◽  
Aline C. L. Moraes ◽  
...  

AbstractAcrocomia (Arecaceae) is a genus widely distributed in tropical and subtropical America that has been achieving economic interest due to the great potential of oil production of some of its species. In particular A. aculeata, due to its vocation to supply oil with the same productive capacity as the oil palm even in areas with water deficit. Although eight species are recognized in the genus, the taxonomic classification based on morphology and geographic distribution is still controversial. Knowledge about the genetic diversity and population structure of the species is limited, which has limited the understanding of the genetic relationships and the orientation of management, conservation, and genetic improvement activities of species of the genus. In the present study, we analyzed the genomic diversity and population structure of seven species of Acrocomia including 117 samples of A. aculeata covering a wide geographical area of occurrence, using single nucleotide Polymorphism (SNP) markers originated from Genotyping By Sequencing (GBS). The genetic structure of the Acrocomia species were partially congruent with the current taxonomic classification based on morphological characters, recovering the separation of the species A. aculeata, A. totai, A. crispa and A. intumescens as distinct taxonomic groups. However, the species A. media was attributed to the cluster of A. aculeata while A. hassleri and A. glauscescens were grouped together with A. totai. The species that showed the highest and lowest genetic diversity were A. totai and A. media, respectively. When analyzed separately, the species A. aculeata showed a strong genetic structure, forming two genetic groups, the first represented mainly by genotypes from Brazil and the second by accessions from Central and North American countries. Greater genetic diversity was found in Brazil when compared to the other countries. Our results on the genetic diversity of the genus are unprecedented, as is also establishes new insights on the genomic relationships between Acrocomia species. It is also the first study to provide a more global view of the genomic diversity of A. aculeata. We also highlight the applicability of genomic data as a reference for future studies on genetic diversity, taxonomy, evolution and phylogeny of the Acrocomia genus, as well as to support strategies for the conservation, exploration and breeding of Acrocomia species and in particular A. aculeata.


2009 ◽  
Vol 54 (No. 10) ◽  
pp. 468-474 ◽  
Author(s):  
S. Kusza ◽  
E. Gyarmathy ◽  
J. Dubravska ◽  
I. Nagy ◽  
A. Jávor ◽  
...  

In this study genetic diversity, population structure and genetic relationships of Tsigai populations in Slovakia were investigated using microsatellite markers. Altogether 195 animals from 12 populations were genotyped for 16 microsatellites. 212 alleles were detected on the loci. The number of identified alleles per locus ranged from 11 to 35. In the majority of the populations heterozygosity deficiency and potential risks of inbreeding could be determined. High values of <I>F</I><sub>ST</sub> (0.133) across all the loci revealed a substantial degree of population differentiation. The estimation of genetic distance value showed that the Slovak Vojin population was the most different from the other populations. The 12 examined populations were able to group into 4 clusters. With this result our aim is to help the Slovak sheep breeders to establish their own mating system, to avoid genetic loss and to prevent diversity of Tsigai breed in Slovakia.


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