Cristina Gardenal | Universidad Nacional de Córdoba (original) (raw)

Papers by Cristina Gardenal

PLoS ONE, 2011

Until recently, the genus Epicrates (Boidae) presented only one continental species, Epicrates ce... more Until recently, the genus Epicrates (Boidae) presented only one continental species, Epicrates cenchria, distributed in Central and South America, but after a taxonomic revision using morphologic characters five species were recognized: E. cenchria, E. crassus, E. maurus, E. assisi, and E. alvarezi. We analyzed two independent data sets, environmental niche models and phylogeny based on molecular information, to explore species delimitation in the continental species of this genus. Our results indicated that the environmental requirements of the species are different; therefore there are not evidences of ecological interchangeability among them. There is a clear correlation between species distributions and the major biogeographic regions of Central and South America. Their overall distribution reveals that allopatry or parapatry is the general pattern. These evidences suggest that habitat isolation prevents or limits gene exchange among them. The phylogenetic reconstruction showed that the continental Epicrates are monophyletic, being E. alvarezi the sister species for the remaining two clades: E. crassus -E. assisi, and E. maurus -E. cenchria. The clade grouping the continental Epicrates is the sister taxon of the genus Eunectes and not of the Caribbean Epicrates clade, indicating that the genus is paraphyletic. There is a non-consistent pattern in niche evolution among continental Epicrates. On the contrary, a high variation and abrupt shifts in environmental variables are shown when ancestral character states were reconstructed on the sequence-based tree. The degree of genetic and ecological divergence among continental Epicrates and the phylogenetic analyses support the elevation to full species of E. cenchria, E. crassus, E. maurus, E. assisi, and E. alvarezi. Citation: Rivera PC, Di Cola V, Martínez JJ, Gardenal CN, Chiaraviglio M (2011) Species Delimitation in the Continental Forms of the Genus Epicrates (Serpentes, Boidae) Integrating Phylogenetics and Environmental Niche Models. PLoS ONE 6(9): e22199.

Zoological Journal of the Linnean Society, 2014

Several species of the genus Oligoryzomys are natural hosts of different hantavirus genotypes aff... more Several species of the genus Oligoryzomys are natural hosts of different hantavirus genotypes affecting humans. The systematics of the genus is confusing, which complicates the identification of the rodent host and hence the potential endemic areas of hantavirus pulmonary syndrome. In this study, we analyse molecular data to infer phylogenetic relationships among Central and South American specimens of Oligoryzomys, and compare our results with previously published data on karyotypic, geographic distribution and host–virus associations to solve contradictory taxonomic reports. We identified 25 clades, each one corresponding to a different putative species. The phylogenetic trees show that Oligoryzomys longicaudatus is strongly related to the Oligoryzomys flavescens complex, which comprises four clades; Oligoryzomys nigripes is related to Oligoryzomys stramineus, Oligoryzomys vegetus is related to Oligoryzomys fulvescens from Central America, and Oligoryzomys brendae is the sister species of Oligoryzomys aff. destructor. We identified the following rodent host–hantavirus genotype relationships: O. longicaudatus–Andes; O. flavescens ‘West’–Bermejo; O. flavescens ‘East’–Lechiguanas; O. nigripes–Juquitiba; Oligoryzomys microtis–Rio Mamore and Rio Mamore-3; Oligoryzomys chacoensis–Oran; Oligoryzomys costaricencis–Choclo; Oligoryzomys delicatus–Maporal; Oligoryzomys utiaritensis–Castelo dos Sonhos; Oligoryzomys sp. RT2012–Rio Mamore-4; Oligoryzomys sp. (and not Oligoryzomys fornesi)–Anajatuba. This work, besides contributing to the development
of prevention programmes for hantavirus epidemiology in Latin America, represents a comprehensive update of the systematics of the genus Oligoryzomys.

Journal of Mammalogy, 2006

ABSTRACT Calomys musculinus is the natural reservoir of Junin virus, the etiological agent of Arg... more ABSTRACT Calomys musculinus is the natural reservoir of Junin virus, the etiological agent of Argentine hemorrhagic fever. In this paper we measure the effective size of 2 populations of the rodent over a 2-year period. Twenty enzyme-coding loci were analyzed using vertical starch gel electrophoresis. Effective population sizes (Nes) were estimated by the pseudolikelihood method in 2 populations 280 km apart in central Argentina. Both populations experienced marked seasonal changes in relative density and in Ne (between 19.8 and infinity). Changes in percentage of polymorphic loci and mean number of alleles per locus were statistically significant and were roughly correlated with density and Ne. Observed changes in heterozygosity, in contrast, were not significant. After low-density periods, mixing of surviving individuals coming from different demes may play an important role in the maintenance of variability and recovery of Ne in populations of C. musculinus.

Annals of The Entomological Society of America, 2002

Journal of Medical Entomology, 2001

Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) polymorphism was analyzed i... more Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) polymorphism was analyzed in five Aedes aegypti (L.) populations from Argentina and one from Puerto Rico to estimate levels of intraspecific polymorphism and genetic relatedness. Allele frequencies were estimated assuming that RAPD products segregate as dominants and that genotype frequencies at those loci are in Hardy-Weinberg equilibrium. Mean expected heterozygosity (He) was 0.350; F(ST) values were significant at all loci except one, supporting the usefulness of the fragments used here to discriminate among populations. Rogers' genetic similarity between samples ranged from 0.806 to 0.621. The population from Puerto Rico was the most different from the Argentina populations. Considering that Ae. aegypti eggs, larvae, and pupae can be transported easily, relationships among the Argentinian populations may reflect the routes and intensity of commercial transit.

Genetica, 1997

In species acting as hosts of infectious agents, the extent of gene flow between populations is o... more In species acting as hosts of infectious agents, the extent of gene flow between populations is of particular interest because the expansion of different infectious diseases is usually related to the dispersal of the host. We have estimated levels of gene flow among populations of the sigmodontine rodent Oligoryzomys flavescens, in which high titers of antibodies have been detected for

Hereditas, 1994

Graomys griseoflavus is a South American murid rodent showing a high degree of chromosomal polymo... more Graomys griseoflavus is a South American murid rodent showing a high degree of chromosomal polymorphism. We have recently demonstrated that cytotypes 2n = 36-38 form a complex reproductively isolated from the kariomorph 2n = 42, and that they may be considered separate species. Given the importance of olfactory perception for precopulatory recognition, we have investigated the ability of G. griseoflavus females to distinguish between odiferous stimuli from conspecific and heterospecific males by means of olfactory discrimination tests.

Heredity, 2004

The geographic distribution of haplotype diversity in the rodent Calomys musculinus, sampled from... more The geographic distribution of haplotype diversity in the rodent Calomys musculinus, sampled from 16 wild populations of Argentina, was analysed on two geographical scales. The species is the natural reservoir of the Junin virus, the etiological agent of the Argentine haemorrhagic fever (AHF). In all, 24 composite haplotypes were recognised in the mtDNA D-loop region. Haplotypes 1 and 2, internal

Genome, 2008

In a previous phylogeographic study of the rodent Calomys musculinus, 24 haplotypes of the mitoch... more In a previous phylogeographic study of the rodent Calomys musculinus, 24 haplotypes of the mitochondrial DNA D-loop region were detected using the restriction fragment length polymorphism technique (PCR-RFLP). Seven percent of the individuals showed patterns in which the sum of the sizes of the restriction fragments exceeded the size of the original PCR product. In the present paper we analyze possible causes of these atypical haplotypes. PCR products were cloned, and two or three different clones from a single individual were detected by their RFLP patterns. Nine clones with different restriction patterns were selected for sequence analyses. A maximum parsimony phylogenetic analysis revealed two well-supported paraphyletic groups. One group comprised sequences showing low nucleotide divergence compared with the most common haplotypes detected in the phylogeographic study. The other group was basal to the three species of Calomys other than C. musculinus included in the study; the mutations in the short portion of the cytochrome b gene amplified corresponded to 12 amino acid substitutions. The results suggest that two independent insertions of mtDNA sequences into the nucleus occurred; these sequences would co-amplify in the PCR procedure. Identification of pseudogenes is crucial to obtain reliable reconstruction of the intraspecific genealogy in phylogeographic studies.

Biochemical Systematics and Ecology, 2002

Calomys musculinus, Calomys laucha and Calomys venustus are cryptic species with overlapping dist... more Calomys musculinus, Calomys laucha and Calomys venustus are cryptic species with overlapping distribution ranges. C. musculinus is the natural reservoir of Junin virus (Arenaviridae), the etiological agent of Argentine Hemorrhagic Fever. In epidemiological studies it is very important to unequivocally identify the species of individuals collected in the field in order to test virus infection. The purpose of this work

Molecular ecology resources, 2008

The rodent Oligoryzomys longicaudatus or long-tailed pygmy rice rat is the reservoir of the aetio... more The rodent Oligoryzomys longicaudatus or long-tailed pygmy rice rat is the reservoir of the aetiological agent of the hantavirus pulmonary syndrome in southern Argentina and Chile. We characterize 11 polymorphic microsatellite loci which would be useful for studies on microgeographical population structure in the species. Amplification of these loci in 42 individuals from four natural populations revealed four to 21 alleles per locus, and values of observed heterozygosities ranging from 0.371 to 0.896. Cross-species amplifications showed that some of the primers designed may be useful for other species of the genus Oligoryzomys.

Journal of General Virology, 2015

In recent years, the notion of co-speciation between Hantavirus species and their hosts was disca... more In recent years, the notion of co-speciation between Hantavirus species and their hosts was discarded in favour of a more likely explanation: preferential host switching. However, the relative importance of this last process in shaping the evolutionary history of hantaviruses remains uncertain, given the present limited knowledge not only of virus-host relationships but also of the pathogen and reservoir phylogenies. In South America, more than 25 hantavirus genotypes were detected; several of them act as etiological agents of the Hantavirus Pulmonary Syndrome (HPS). The understanding of the diversity of hantaviruses and of the processes underlying host switching is critical since human cases of HPS are almost exclusively the result of human-host interactions. In this study, we tested if preferential host switching is the main process driving hantavirus diversification in South America, by performing a co-phylogenetic analysis of the viruses and their primary hosts. We also suggest a new level of amino acid divergence to define virus species in the group. Our results indicate that preferential host switching would not be the main process driving virus diversification. The historical geographic proximity among rodent hosts emerges as an alternative hypothesis to be tested.

The genetic structure of populations of the Sigmodontinae rodent Calomys laucha was studied by me... more The genetic structure of populations of the Sigmodontinae rodent Calomys laucha was studied by means of allozyme electrophoresis. This highly opportunistic species is found preferably in periodically perturbed habitats of crop fields in central Argentina, where it can attain very high densities. A total of 17 enzymatic proteins assayed gave information on 25 loci; only four were monomorphic in the seven populations studied. Levels of genetic variability (H o from 0.144 to 0.171; P 95% from 44% to 56%) were higher than mean values reported for mammals and rodents. These high levels of heterozygosity could be maintained by large populations that do not experience great fluctuations in size, or by a social structure consistent in many small breeding groups that are formed and dissappear every breeding season. Genetic differentiation at a macrogeographical scale (θ=0.018) was low but statistically significant, and showed no correlation with geographic distance between pairs of populations. The pattern of population differentiation found is compatible with a relatively recent range expansion. 

In order to contribute to knowledge of colonization patterns in the rodent Calomys musculinus, a ... more In order to contribute to knowledge of colonization patterns in the rodent Calomys musculinus, a natural reservoir of the virus producing Argentine hemorrhagic fever (AHF), we studied the haplotype diversity of the mitochondrial DNA D-loop region in five natural populations from central Argentina. Digestion with eight restriction enzymes (RsaI, MseI, Tsp509I, AluI, AciI, HaeIII, NlaIII, and AseI) revealed polymorphism in the 1300 bp fragment amplified by PCR. Twenty different composite haplotypes were detected. Hierarchical analyses indicated that almost all variation (94%) is contained within local populations. Haplotypes 1 and 2, shared by all populations, were the most frequent. Nonsignificant genetic differentiation was found among populations of the endemic and nonendemic areas of AHF. All locations sampled presented exclusive haplotypes in spite of their geographic proximity, which would support previous observations indicating restricted gene flow among C. musculinus populations.

Calomys musculinus is a Sigmodontinae rodent inhabiting periodically disturbed habitats in the ce... more Calomys musculinus is a Sigmodontinae rodent inhabiting periodically disturbed habitats in the central eastern plains of Argentina. It is the natural reservoir host of Junin virus, the etiological agent of Argentine Hemorrhagic Fever (AHF). In order to analyze the levels of gene flow among populations of this species, allozymic variability at 26 loci was studied in 291 individuals from the endemic zone of AHF and localities outside it. All populations showed high levels of polymorphism (H e between 0.107 and 0.144; P 95% between 38 and 54%). Individual loci f values were in most cases negative, although not significantly different from zero. Mean genetic differentiation among populations was low, but statistically significant (θ = 0.020; P < 0.01). There was no correlation between genetic and geographic distances between pairs of populations, and scatter of the pairwise points suggests that, at the regional scale, genetic drift is more influential than gene flow. This result can be interpreted as indicative of a relatively recent expansion of C. musculinus habitat and restricted on-going gene flow, which would be compatible with a relatively slow expansion rate of AHF.

Amphibia-reptilia, 2005

Abstract. Boa constrictor occidentalis, the only subspecies of the genus Boa present in Argentina... more Abstract. Boa constrictor occidentalis, the only subspecies of the genus Boa present in Argentina, is endangered because of the strong hunting pressure due to the skin and pet-shop trade and the destruction and fragmentation of its habitat. We estimated levels of protein ...

Biochemical Genetics, 1980

NAD-linked lactate, malate, glycerophosphate, alcohol and nonspecific dehydrogenases, aspartate a... more NAD-linked lactate, malate, glycerophosphate, alcohol and nonspecific dehydrogenases, aspartate aminotransferases, and soluble esterases from extracts of tissues of individuals from a wild population of Calomys musculinus (Rodentia, Cricetidae) have been analyzed by means of starch gel electrophoresis and specific staining. Allelic frequencies and heterozygosity have been determined. Mendelian inheritance of some of the variants detected was confirmed by breeding experiments.

Mastozoología Neotropical. Instituto Argentino de Investigación de las Zonas Aridas. mnsarem@lab.... more Mastozoología Neotropical. Instituto Argentino de Investigación de las Zonas Aridas. mnsarem@lab.cricyt.edu.ar. ISSN (Versión impresa): 0327-9383. ISSN (Versión en línea): 1666-0536. ARGENTINA. 2005. María C. Provensal ...

Hereditas, 1990

Enzyme polymorphism was studied by means of starch gel electrophoresis on five population samples... more Enzyme polymorphism was studied by means of starch gel electrophoresis on five population samples of Calomys laucha collected in different sites and seasons. C. laucha, a cricetid rodent inhabiting preferentially cultivated fields in the central-eastem plains of Argentina, is a reservoir-host of Junin virus, agent of Argentine hemorrhagic fever. Results show high levels of genic variability in all the samples (P from 62.50 to 77.27 ; H from 0.1 18 to 0.163) and low genetic distance among populations (D from 0.0024 to 0,0167). Estimations of gene flow (mean Nm = 10.78) indicate a high migration capability of the species and the possibility of further dispersal of Junin virus.