Morphological and molecular evidence for two new species of Tetragonopterus (Characiformes: Characidae) from central Brazil

The combination of morphological and molecular data of Tetragonopterus species collected in the Rio Araguaia basin allows the recognition of two undescribed species that are presented in this article. These species are distinguished from their congeners (Tetragonopterus anostomus, Tetragonopterus argenteus, Tetragonopterus carvalhoi, Tetragonopterus chalceus and Tetragonopterus rarus) by characters related to the number and morphology of the teeth, the numbers of gill rakers on the upper and lower limbs of the first gill arch, the number of predorsal scales and the overall colour pattern. In addition, the analysis of mitochondrial DNA sequences identified an accentuated genetic distance between these two new species and their congeners. A discussion of the phylogenetic relationships within Tetragonopterus is provided. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

First cytogenetic information for Drymoreomys albimaculatus (Rodentia, Cricetidae), a recently described genus from Brazilian Atlantic forest

The recently described taxon Drymoreomys albimaculatus is endemic to the Brazilian Atlantic Forest and its biology and genetics are still poorly known. Herein, we present, for the first time, the karyotype of the species using classical and molecular cytogenetics, which showed 2n=62, FN=62, and interstitial telomeric signals at the sex chromosomes. Nuclear and mitochondrial DNA sequences from the two karyotyped individuals verify the taxonomic identity as the recently described D. albimaculatus and confirm the relationship of the species with other Oryzomyini. Additionally, external morphological information is provided. © Elkin Y. Suárez-Villota et al.

Description of larva of Amblyomma romitii (Acari: Ixodidae) by optical and scanning electron microscopy, including porotaxy and phylogenetic analysis

The description of the larva of Amblyomma romitii Tonelli-Rondelli is based on optical and scanning electron microscopy. Larvae were obtained under laboratory conditions from an engorged female collected on capybara from Rurópolis municipality, State of Pará, Northern Brazil. Several characters are presented including the chaetotaxy of idiosoma, palpi and Haller's organ. The larval porotaxy (topographical and numerical patterns of integumentary structures) was presented and compared to that of the other Amblyomma spp. larvae. The mitochondrial 16S rDNA partial sequence of A. romitii generated in the present study was aligned with sequences previously determined for other Amblyomma species available in Genbank and with some species presently sequenced. The larval morphology of A. romitii and other Neotropical Amblyomma spp. larvae is discussed as well as the DNA sequence and its phylogenetic position among other species of the genus. © 2012 Springer Science+Business Media Dordrecht.

Comparative cytogenetic analysis of some species of the Dendropsophus microcephalus group (Anura, Hylidae) in the light of phylogenetic inferences

Background: Dendropsophus is a monophyletic anuran genus with a diploid number of 30 chromosomes as an important synapomorphy. However, the internal phylogenetic relationships of this genus are poorly understood. Interestingly, an intriguing interspecific variation in the telocentric chromosome number has been useful in species identification. To address certain uncertainties related to one of the species groups of Dendropsophus, the D. microcephalus group, we carried out a cytogenetic analysis combined with phylogenetic inferences based on mitochondrial sequences, which aimed to aid in the analysis of chromosomal characters. Populations of Dendropsophus nanus, Dendropsophus walfordi, Dendropsophus sanborni, Dendropsophus jimi and Dendropsophus elianeae, ranging from the extreme south to the north of Brazil, were cytogenetically compared. A mitochondrial region of the ribosomal 12S gene from these populations, as well as from 30 other species of Dendropsophus, was used for the phylogenetic inferences. Phylogenetic relationships were inferred using maximum parsimony and Bayesian analyses.Results: The species D. nanus and D. walfordi exhibited identical karyotypes (2n = 30; FN = 52), with four pairs of telocentric chromosomes and a NOR located on metacentric chromosome pair 13. In all of the phylogenetic hypotheses, the paraphyly of D. nanus and D. walfordi was inferred. D. sanborni from Botucatu-SP and Torres-RS showed the same karyotype as D. jimi, with 5 pairs of telocentric chromosomes (2n = 30; FN = 50) and a terminal NOR in the long arm of the telocentric chromosome pair 12. Despite their karyotypic similarity, these species were not found to compose a monophyletic group. Finally, the phylogenetic and cytogenetic analyses did not cluster the specimens of D. elianeae according to their geographical occurrence or recognized morphotypes.Conclusions: We suggest that a taxonomic revision of the taxa D. nanus and D. walfordi is quite necessary. We also observe that the number of telocentric chromosomes is useful to distinguish among valid species in some cases, although it is unchanged in species that are not necessarily closely related phylogenetically. Therefore, inferences based on this chromosomal character must be made with caution; a proper evolutionary analysis of the karyotypic variation in Dendropsophus depends on further characterization of the telocentric chromosomes found in this group. © 2013 Medeiros et al.; licensee BioMed Central Ltd.

Evolutionary dynamics of retrotransposable elements Rex1, Rex3 and Rex6 in neotropical cichlid genomes

Background: Transposable elements (TEs) have the potential to produce broad changes in the genomes of their hosts, acting as a type of evolutionary toolbox and generating a collection of new regulatory and coding sequences. Several TE classes have been studied in Neotropical cichlids; however, the information gained from these studies is restricted to the physical chromosome mapping, whereas the genetic diversity of the TEs remains unknown. Therefore, the genomic organization of the non-LTR retrotransposons Rex1, Rex3, and Rex6 in five Amazonian cichlid species was evaluated using physical chromosome mapping and DNA sequencing to provide information about the role of TEs in the evolution of cichlid genomes. Results: Physical mapping revealed abundant TE clusters dispersed throughout the chromosomes. Furthermore, several species showed conspicuous clusters accumulation in the centromeric and terminal portions of the chromosomes. These TE chromosomal sites are associated with both heterochromatic and euchromatic regions. A higher number of Rex1 clusters were observed among the derived species. The Rex1 and Rex3 nucleotide sequences were more conserved in the basal species than in the derived species; however, this pattern was not observed in Rex6. In addition, it was possible to observe conserved blocks corresponding to the reverse transcriptase fragment of the Rex1 and Rex3 clones and to the endonuclease of Rex6. Conclusion: Our data showed no congruence between the Bayesian trees generated for Rex1, Rex3 and Rex6 of cichlid species and phylogenetic hypothesis described for the group. Rex1 and Rex3 nucleotide sequences were more conserved in the basal species whereas Rex6 exhibited high substitution rates in both basal and derived species. The distribution of Rex elements in cichlid genomes suggests that such elements are under the action of evolutionary mechanisms that lead to their accumulation in particular chromosome regions, mostly in heterochromatins. © 2013 Schneider et al.; licensee BioMed Central Ltd.

Cross-mating experiments detect reproductive compatibility between Triatoma sherlocki and other members of the Triatoma brasiliensis species complex

Phylogenetic approaches based on mitochondrial DNA variation (fragments of Cyt B and 16S ribosomal RNA) have revealed Triatoma sherlocki as the most recent species addition to the Triatoma brasiliensis species complex; a monophyletic group which includes T. brasiliensis, Triatoma melanica, and Triatoma juazeirensis. T. sherlocki is the most differentiated among all species of this complex: it is unable to fly, possesses longer legs than the other members, and has reddish tonality in some parts of its exochorion. We question whether these species are reproductively compatible because of this pronounced morphological differentiation, and therefore, we present a series of cross breeding experiments that test compatibility between T. sherlocki and other members of the T. brasiliensis complex. We extended our analyses to include crosses between T. sherlocki and Triatoma lenti, because the latter has been suggested as a possible member of this complex. T. sherlocki male. ×. T. lenti female pairs failed to produce hybrids. All other crosses of T. sherlocki and members of T. brasiliensis species complex, as well as backcrosses, produced viable offspring through the third generation. This study stresses the importance of searching for the features that may isolate members of the T. brasiliensis species complex. © 2013 Elsevier B.V.

Análises moleculares e da presença de endobactérias de Camponotus textor Forel, 1899 (Hymenoptera, Formicidae)

Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC

Expressão de genes relacionados à função mitocondrial em bovinos Nelore extremos para consumo alimentar residual

Pós-graduação em Genética e Melhoramento Animal - FCAV

Caracterização da estrutura genética populacional do tubarão-crocodilo (Pseudocarcharias kamoharai) no Atlântico equatorial utilizando marcadores moleculares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relação filogenètica entre sete espécies de Triatominae (Hemiptera, Reduviidae) da região Centro-Oeste do Brasil baseada no sequenciamento de genes mitocondriais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evolução do sistema reprodutivo de formigas da tribo Attini (Hymenoptera : myrmiciane): análise das espermatecas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aplicação da genética molecular no manejo e conservação de tubarões

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Origem do suíno casco-de-burro e sua relação genética com populações ibéricas e americanas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genetic characterization of native and introduced populations of the neotropical cichlid genus Cichla in Brazil

A molecular phylogenetic analysis based on mitochondrial 16S ribosomal DNA and Control Region sequences from native and introduced populations was undertaken, in order to characterize the introduction of Cichla (peacock bass or tucunaré) species in Brazil. Mitochondrial DNA haplotypes found in introduced fish from Minas Gerais state (southeastern Brazil) clustered only with those from native species of the Tocantins River (Cichla piquiti and C. kelberi), thereby suggesting a single or, at most, few translocation acts in this area, even though with fish from the same source-population. Our study contributes to an understanding of the introduction of Cichla in regions of Brazil outside the Amazon basin, and adds phylogenetic data to the recently describe Cichla species, endemic from the Tocantins-Araguaia basin.

Population analysis of Scomberomorus cavalla (Cuvier, 1829) (Perciformes, Scombridae) from the Northern and Northeastern coast of Brazil

Scomberomorus cavalla é uma espécie de peixe pelágico amplamente distribuído na costa oeste do Atlântico, e uma diminuição no seu nível de captura tem sido verificada nos E.U.A e Golfo do México, comparada com os níveis alcançados pela espécie no passado. Da mesma forma, em algumas áreas do Brasil, há indícios de sobre-exploração. Entretanto, não existem estudos moleculares que visam o manejo deste importante item. Desta forma, no presente estudo, foram seqüenciados 380 pares de bases nucleotídicas da região da Alça-D do DNA mitocondrial de amostras provenientes de desembarque em Macapá, Bragança e Fortaleza. As análises filogenéticas e populacionais revelaram que há apenas uma população panmítica e baixos níveis de variabilidade genética foram observados. Estes resultados, assim como a observada sobre-exploração de S. cavala, representam dados muito importantes para o estabelecimento do manejo deste estoque a fim de prevenir um colapso ou risco de extinção no futuro.