Montevideo, Uruguay
Montevideo, Uruguay

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Garcia G.,Seccion Genetica Evolutiva | Gutierrez V.,Seccion Genetica Evolutiva | Vergara J.,Seccion Genetica Evolutiva | Vergara J.,CONICET | And 3 more authors.
Journal of Biogeography | Year: 2012

Aim To elucidate the role of vicariance versus dispersal at the microevolutionary scale in annual killifish populations belonging to the Austrolebias bellottii species complex (Rivulidae). Within this complex, A. bellottii and A. apaii have low vagility and occur widely within the study area, making them excellent models for testing biogeographic hypotheses of differentiation. Location South America, in the Paraná-Uruguay-La Plata river basin. Methods Molecular data and morphometric analyses were used to reconstruct the phylogeographic history and morphological variation of 24 populations of two taxa of the A. bellottii species complex. Phylogenetic analyses using maximum likelihood (ML) and Bayesian inference (BI) model-based methods, estimates of clade divergence times implemented in beast, non-metric multidimensional scaling, analysis of molecular variance results, and morphological analyses elucidated the role of vicariance versus dispersal hypotheses in population differentiation in the aforementioned river basin. Results In the A. bellottii species complex from the Paraná-Uruguay-La Plata river basin, past allopatric fragmentation from vicariance events seems to be the most plausible scenario for diversification since the Late Miocene and more recently since the Plio-Pleistocene. The Plio-Pleistocene vicariance produced the differentiation of three major clades in A. bellottii populations. One clade from the eastern Uruguay River drainage was separated from another in western Uruguay and the Paraná-La Plata River drainages. A later vicariance event split populations to the south (lower Paraná-La Plata Basin) and north (middle Paraná) of the western Paraná River drainage. However, our results do not exclude the possibility of dispersal events among A. bellottii populations from both the Uruguay and Paraná river drainages, which could occur in these river basins during hypothesized connectivity cycles of the Late Pliocene and Pleistocene. Main conclusions Past allopatric fragmentation caused by different vicariance events seems to be the main driver of diversification in the A. bellottii species complex since the Plio-Pleistocene. However, the current molecular data suggest that populations from both drainages of the Paraná-Uruguay rivers may have experienced cycles of connectivity during the Pleistocene, perhaps including multiple vicariance or dispersal events from populations located in the western lower Uruguay River drainage, which encompassed climatic and geological changes in the Paraná-Uruguay-La Plata Basin. © 2012 Blackwell Publishing Ltd.


PubMed | University of the Republic of Uruguay, University of Padua, Seccion Genetica Evolutiva and University of the Sea
Type: Journal Article | Journal: BMC veterinary research | Year: 2016

Campylobacter fetus is a pathogen of major concern for animal and human health. The species shows a great intraspecific variation, with three subspecies: C. fetus subsp. fetus, C. fetus subsp. venerealis, and C. fetus subsp. testudinum. Campylobacter fetus fetus affects a broad range of hosts and induces abortion in sheep and cows. Campylobacter fetus venerealis is restricted to cattle and causes the endemic disease bovine genital campylobacteriosis, which triggers reproductive problems and is responsible for major economic losses. Campylobacter fetus testudinum has been proposed recently based on genetically divergent strains isolated from reptiles and humans. Both C. fetus fetus and C. fetus testudinum are opportunistic pathogens for immune-compromised humans. Biochemical tests remain as the gold standard for identifying C. fetus but the fastidious growing requirements and the lack of reliability and reproducibility of some biochemical tests motivated the development of molecular diagnostic tools. These methods have been successfully tested on bovine isolates but fail to detect some genetically divergent strains isolated from other hosts. The aim of the present study was to develop a highly specific molecular assay to identify and quantify C. fetus strains.We developed a highly sensitive real-time PCR assay that targets a unique region of the 16S rRNA gene. This assay successfully detected all C. fetus strains, including those that were negative for the cstA gene-based assay used as a standard for molecular C. fetus identification. The assay showed high specificity and absence of cross-reactivity with other bacterial species. The analytical testing of the assay was determined using a standard curve. The assay demonstrated a wide dynamic range between 10The possibility to characterize samples in a rapid, sensitive and reproducible way makes this assay a good option to establish a new standard in molecular identification and quantification of C. fetus species.


Iraola G.,Institute Pasteur Montevideo | Perez R.,Seccion Genetica Evolutiva | Naya H.,Institute Pasteur Montevideo | Paolicchi F.,University of the Sea | And 6 more authors.
Genome Biology and Evolution | Year: 2014

The genus Campylobacter includes some of the most relevant pathogens for human and animal health; the continuous effort in their characterization has also revealed new species putatively involved in different kind of infections. Nowadays, the available genomic data for the genus comprise a wide variety of species with different pathogenic potential and niche preferences. In this work, we contribute to enlarge this available information presenting the first genome for the species Campylobacter sputorum bv. Sputorum and use this and the already sequenced organisms to analyze the emergence and evolution of pathogenicity and niche preferences among Campylobacter species. We found that campylobacters can be unequivocally distinguished in established and putative pathogens depending on their repertory of virulence genes, which have been horizontally acquired from other bacteria because the nonpathogenic Campylobacter ancestor emerged, and posteriorly interchanged between some members of the genus. Additionally, we demonstrated the role of both horizontal gene transfers and diversifying evolution in niche preferences, being able to distinguish genetic features associated to the tropism for oral, genital, and gastrointestinal tissues. In particular, we highlight the role of nonsynonymous evolution of disulphide bond proteins, the invasion antigen B (CiaB), and other secreted proteins in the determination of niche preferences. Our results arise from assessing the previously unmet goal of considering the whole available Campylobacter diversity for genome comparisons, unveiling notorious genetic features that could explain particular phenotypes and set the basis for future research in Campylobacter biology. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.


PubMed | Seccion Genetica Evolutiva, University of the Sea and Institute Pasteur Montevideo
Type: Journal Article | Journal: Genome biology and evolution | Year: 2014

The genus Campylobacter includes some of the most relevant pathogens for human and animal health; the continuous effort in their characterization has also revealed new species putatively involved in different kind of infections. Nowadays, the available genomic data for the genus comprise a wide variety of species with different pathogenic potential and niche preferences. In this work, we contribute to enlarge this available information presenting the first genome for the species Campylobacter sputorum bv. sputorum and use this and the already sequenced organisms to analyze the emergence and evolution of pathogenicity and niche preferences among Campylobacter species. We found that campylobacters can be unequivocally distinguished in established and putative pathogens depending on their repertory of virulence genes, which have been horizontally acquired from other bacteria because the nonpathogenic Campylobacter ancestor emerged, and posteriorly interchanged between some members of the genus. Additionally, we demonstrated the role of both horizontal gene transfers and diversifying evolution in niche preferences, being able to distinguish genetic features associated to the tropism for oral, genital, and gastrointestinal tissues. In particular, we highlight the role of nonsynonymous evolution of disulphide bond proteins, the invasion antigen B (CiaB), and other secreted proteins in the determination of niche preferences. Our results arise from assessing the previously unmet goal of considering the whole available Campylobacter diversity for genome comparisons, unveiling notorious genetic features that could explain particular phenotypes and set the basis for future research in Campylobacter biology.


Garcia G.,Seccion Genetica Evolutiva | Rios N.,Seccion Genetica Evolutiva | Gutierrez V.,Seccion Genetica Evolutiva | Varela J.G.,University of Santiago de Compostela | And 3 more authors.
PLoS ONE | Year: 2014

The present paper integrates phylogenetic and population genetics analyses based on mitochondrial and nuclear molecular markers in silversides, genus Odontesthes, from a non-sampled area in the SW Atlantic Ocean to address species discrimination and to define Managements Units for sustainable conservation. All phylogenetic analyses based on the COI mitochondrial gene were consistent to support the monophyly of the genus Odontesthes and to include O. argentinensis , O. perugiae-humensis and some O. bonariensis haplotypes in a basal polytomy conforming a major derivative clade. Microsatellites data revealed somewhat higher genetic variability values in the O. argentinensis-perugia populations than in O. bonariensis and O. perugia-humensis taxa. Contrasting population genetics structuring emerged from mitochondrial and microsatellites analyses in these taxa. Whereas mitochondrial data supported two major groups ( O. argentinensis-perugiahumensis vs. O. bonariensis-perugiae-humensis populations), microsatellite data detected three major genetic entities represented by O. bonariensis, O. perugiae-humensis and an admixture of populations belonging to O. argentinensis-perugiae respectively. Therefore, the star COI polytomy in the tree topology involving these taxa could be interpreted by several hypothetic scenarios such as the existence of shared ancestral polymorphisms, incomplete lineage sorting in a radiating speciation process and/or reticulation events. Present findings support that promiscuous and recent contact between incipient species sharing asymmetric gene flow exchanges, blurs taxa boundaries yielding complicated taxonomy and Management Units delimitation in silverside genus Odontesthes from SW Atlantic Ocean basins. © 2014 Garcia et al.


PubMed | Seccion Genetica Evolutiva and University of Santiago de Compostela
Type: Journal Article | Journal: PloS one | Year: 2014

The present paper integrates phylogenetic and population genetics analyses based on mitochondrial and nuclear molecular markers in silversides, genus Odontesthes, from a non-sampled area in the SW Atlantic Ocean to address species discrimination and to define Managements Units for sustainable conservation. All phylogenetic analyses based on the COI mitochondrial gene were consistent to support the monophyly of the genus Odontesthes and to include O. argentinensis, O. perugiae-humensis and some O. bonariensis haplotypes in a basal polytomy conforming a major derivative clade. Microsatellites data revealed somewhat higher genetic variability values in the O. argentinensis-perugia populations than in O. bonariensis and O. perugia-humensis taxa. Contrasting population genetics structuring emerged from mitochondrial and microsatellites analyses in these taxa. Whereas mitochondrial data supported two major groups (O. argentinensis-perugia-humensis vs. O. bonariensis-perugiae-humensis populations), microsatellite data detected three major genetic entities represented by O. bonariensis, O. perugiae-humensis and an admixture of populations belonging to O. argentinensis-perugiae respectively. Therefore, the star COI polytomy in the tree topology involving these taxa could be interpreted by several hypothetic scenarios such as the existence of shared ancestral polymorphisms, incomplete lineage sorting in a radiating speciation process and/or reticulation events. Present findings support that promiscuous and recent contact between incipient species sharing asymmetric gene flow exchanges, blurs taxa boundaries yielding complicated taxonomy and Management Units delimitation in silverside genus Odontesthes from SW Atlantic Ocean basins.


Novello A.,Seccion Genetica Evolutiva | Villar S.,Seccion Genetica Evolutiva | Urioste J.,Laboratorio Celsius
Cytogenetic and Genome Research | Year: 2010

Heterochromatin patterns were analyzed in the genus Ctenomys from Uruguay which exhibits high karyotype variability. Different amounts and localizations of heterochromatin were observed in species and populations analyzed. While species as C. rionegrensis presented heterochromatic arms in all the chromosomes of the karyotype, other species like C. torquatus showed only few chromosomes with pericentric heterochromatin. At the pachytene stage, bivalents merge in densely stained chromocenters. We detected in these chromocenters the typical highly repeated DNA of this genus after in situ hybridization, the M31 chromodomain through immunofluorescence as well as dense Giemsa staining after C-banding. In species that present low amounts of heterochromatin, only 1 or 2 chromocenters were observed in which bivalents merge as observed in C. rionegrensis. After BRCA1 immunodetection we observed in early pachytene cells positive spots located over heterochromatic chromocenters that strongly suggest heterochromatic DNA repair. Mechanical stress mainly due to increasing chromatin compactness before metaphase I might be a mechanism to spread heterochromatin between different chromosomes within a karyotype. Copyright © 2010 S. Karger AG, Basel.


Delgado C.,Seccion Genetica Evolutiva | Garcia G.,Seccion Genetica Evolutiva
Parasitology Research | Year: 2015

In recent years, molecular studies in host-parasite interactions in terms of coevolution have become important. Larvae (L3) of two species of Contracaecum were found parasitizing species of Rivulidae in the Atlantic coastal basins from Uruguay. The aim of this study is to determine the patterns of differentiation of this host-parasite complex in order to clarify possible coevolutionary events in such interaction throughout phylogeographic approach using both nuclear and mitochondrial molecular markers (internal transcribed spacers (ITS) and cytochrome oxidase subunit 1 (cox-1)). Based on both markers, intraspecific variation in Contracaecum species was lower than 2 %, while interspecific variation was greater than 10 %. Both species of Contracaecum constitute monophyletic groups. Contracaecum resulted in a paraphyletic genus when incorporating other Contracaecum species and closely related nematode sequences from GenBank. ITS regions showed that Contracaecum sp. 1 is more closely related to other species of the same genus than with their counterparts from Atlantic coastal basins in Uruguay. Haplotype network for both markers corroborate the existence of two distinct taxa. While ITS pairwise FST comparisons and the indirect estimate of gene flow confirm the existence of two distinct Contracaecum species, mitochondrial gene detected low levels of migrants between some of the populations from both species. Our results suggest that coevolution in this host-parasite complex species is plausible. Parasite cladogenetic events occur almost simultaneously with the separation of the hypothetical ancestors of each species complex of Austrolebias during Pliocene. Additionally, the two lineages of Contracaecum colonize differently the species within each of the Austrolebias complexes. © 2014, Springer-Verlag Berlin Heidelberg.


Garcia G.,Seccion Genetica Evolutiva | Rios N.,Seccion Genetica Evolutiva | Gutierrez V.,Seccion Genetica Evolutiva
Genetica | Year: 2015

Among Neotropical fish fauna, the South American killifish genus Austrolebias (Cyprinodontiformes: Rivulidae) constitutes an excellent model to study the genomic evolutionary processes underlying speciation events. Recently, unusually large genome size has been described in 16 species of this genus, with an average DNA content of about 5.95 ± 0.45 pg per diploid cell (mean C-value of about 2.98 pg). In the present paper we explore the possible origin of this unparallel genomic increase by means of comparative analysis of the repetitive components using NGS (454-Roche) technology in the lowest and highest Rivulidae genomes. Here, we provide the first annotated Rivulidae-repeated sequences composition and their relative repetitive fraction in both genomes. Remarkably, the genomic proportion of the moderately repetitive DNA in Austrolebias charrua genome represents approximately twice (45 %) of the repetitive components of the highly related rivulinae taxon Cynopoecilus melanotaenia (25 %). Present work provides evidence about the impact of the repeat families that could be distinctly proliferated among sublineages within Rivulidae fish group, explaining the great genome size differences encompassing the differentiation and speciation events in this family. © 2015, Springer International Publishing Switzerland.


Among Neotropical fish fauna, the South American killifish genus Austrolebias (Cyprinodontiformes: Rivulidae) constitutes an excellent model to study the genomic evolutionary processes underlying speciation events. Recently, unusually large genome size has been described in 16 species of this genus, with an average DNA content of about 5.95 0.45 pg per diploid cell (mean C-value of about 2.98 pg). In the present paper we explore the possible origin of this unparallel genomic increase by means of comparative analysis of the repetitive components using NGS (454-Roche) technology in the lowest and highest Rivulidae genomes. Here, we provide the first annotated Rivulidae-repeated sequences composition and their relative repetitive fraction in both genomes. Remarkably, the genomic proportion of the moderately repetitive DNA in Austrolebias charrua genome represents approximately twice (45%) of the repetitive components of the highly related rivulinae taxon Cynopoecilus melanotaenia (25%). Present work provides evidence about the impact of the repeat families that could be distinctly proliferated among sublineages within Rivulidae fish group, explaining the great genome size differences encompassing the differentiation and speciation events in this family.

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