987 resultados para phylogeny


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Moenkhausia is one of the most speciose genera in Characidae, currently composed of 75 nominal species of small fishes distributed across South American hydrographic basins, primarily the Amazon and Guyanas. Despite the large number of described species, studies involving a substantial number of its species designed to better understand their relationships and putative monophyly are still lacking. In this study, we analysed a large number of species of Moenkhausia to test the monophyly of the genus based on the phylogenetic analysis of DNA sequences of two mitochondrial and three nuclear genes. The in-group included 29 species of Moenkhausia, and the out-group was composed of representatives of Characidae and other members of Characiformes. All species of Moenkhausia belong to the same clade (Clade C); however, they appear distributed in five monophyletic groups along with other different genera, which means that Moenkhausia is polyphyletic and indicates the necessity of an extensive revision of the group. © 2013 Blackwell Verlag GmbH.

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Despite their great importance as pests of cultivated plants worldwide, members of the family Tetranychidae have never been subjected to a thorough cladistic analysis to reveal the history and relationships among related genera. Herein, we provide the first phylogenetic analysis and taxonomic review of species of the genera Aponychus, Paraponychus and Stylophoronychus using morphological characters. The results indicate a monophyletic clade uniting the aforementioned genera, although none of the three genera were recovered as monophyletic. We reinstate the tribe Aponychini as the taxon containing those three genera. Aponychus bambusae and A. aequilibris are herein considered junior synonyms of Stylophoronychus vannus and A. corpuzae, respectively. © 2013 CSIRO.

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The PRP8 intein is the most widespread intein among the Kingdom Fungi. This genetic element occurs within the prp8 gene, and is transcribed and translated simultaneously with the gene. After translation, the intein excises itself from the Prp8 protein by an autocatalytic splicing reaction, subsequently joining the N and C terminals of the host protein, which retains its functional conformation. Besides the splicing domain, some PRP8 inteins also have a homing endonuclease (HE) domain which, if functional, makes the intein a mobile element capable of becoming fixed in a population. This work aimed to study (1) The occurrence of this intein in Histoplasma capsulatum isolates (n=. 99) belonging to different cryptic species collected in diverse geographical locations, and (2) The functionality of the endonuclease domains of H. capsulatum PRP8 inteins and their phylogenetic relationship among the cryptic species. Our results suggest that the PRP8 intein is fixed in H. capsulatum populations and that an admixture or a probable ancestral polymorphism of the PRP8 intein sequences is responsible for the apparent paraphyletic pattern of the LAmA clade which, in the intein phylogeny, also encompasses sequences from LAmB isolates. The PRP8 intein sequences clearly separate the different cryptic species, and may serve as an additional molecular typing tool, as previously proposed for other fungi genus, such as Cryptococcus and Paracoccidioides. © 2013 Elsevier B.V.

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The characiform family Gasteropelecidae, the so-called freshwater hatchetfishes, is comprised of three genera and nine species found in Panama and all South American countries except Chile. Our goal was to investigate the molecular characteristics, phylogenetic relationships among the species and genera of Gasteropelecidae and phylogenetic relationships between the Gasteropelecidae family with other Characiformes. DNA fragments from two mitochondrial (16S rRNA and Cytochrome B) and three nuclear genes (Rag1, Rag2 and Myh6) were sequenced. Our results corroborate the morphology-based hypothesized monophyly of the Gasteropelecidae family and most of the relationships among its genera. However, the genus Gasteropelecus is polyphyletic because G. maculatus is placed as the sister group to all other gasteropelecids, whereas G. sternicla is more closely related to species of Carnegiella. Similarly, the species Carnegiella strigata is not monophyletic, which suggests that the family needs a taxonomic review. Moreover, the species Thoracocharax stellatus was composed by four distinct lineages suggesting the this species may represents a species complex. © 2013 Elsevier Inc.

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The PrPC prion protein contains 250 amino acids with some variation among species and is expressed in several cell types. PrPC is converted to PrPSc by a post-translational process in which it acquires amino acid sequences of three-dimensional conformation of -sheets. Variations in the prion protein gene were observed among 16 genera of New World primates (Platyrrhini), and resulted in amino acid substitutions when compared with the human sequence. Seven substitutions not yet described in the literature were found: W  R at position 31 in Cebuella, T  A at position 95 in Cacajao and Chiropotes, N S at position 100 in Brachyteles, L  Q at position 130 in Leontopithecus (in the sequence responsible for generating the -sheet 1), D  E at position 144 in Lagothrix (in the sequence responsible for the -helix 1), D G at position 147 in Saguinus (also located in the -helix 1 region), and M  I at position 232 in Alouatta. The phylogenetic trees generated by parsimony, neighbor-joining and Bayesian analyses strongly support the monophyletic status of the platyrrhines, but did not resolve relationships among families. However, the results do corroborate previous findings, which indicate that the three platyrrhine families radiated rapidly from an ancient split.

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The systematics of the subfamily Callitrichinae (Platyrrhini, Primates), a group of small monkeys from South America and Panama, remains an area of considerable discussion despite many investigations, there being continuing controversy over subgeneric taxonomic classifications based on morphological characters. The purpose of our research was to help elucidate the phylogenetic relationships within the monkey genus Saguinus (Callitrichinae) using a molecular approach to discover whether or not the two different sections containing hairy-faced and bare-faced species are monophyletic, whether Saguinus midas midas and Saguinus bicolor are more closely related than are S. midas midas and Saguinus midas niger, and if Saguinus fuscicollis melanoleucus and Saguinus fuscicollis weddelli really are different species. We sequenced the 957 bp ND1 mitochondrial gene of 21 Saguinus monkeys (belonging to six species and nine morphotypes) and one Cebus monkey (the outgroup) and constructed phylogenetic trees using maximum parsimony, neighbor joining, and maximum likelihood methods. The phylogenetic trees obtained divided the genus Saguinus into two groups, one containing the small-bodied species S. fuscicollis and the other, the large-bodied species S. mystax, S. leucopus, S. oedipus, S. midas, S. bicolor. The most derived taxa, S. midas and S. bicolor, grouped together, while S. fuscicollis melanoleucus and S. f. weddelli showed divergence values that did not support the division of these morphotypes into subspecies. On the other hand, S. midas individuals showed divergence compatible with the existence of three subspecies, two of them with the same morphotype as the subspecies S. midas niger. The results of our study suggest that there is at least one Saguinus subspecies that has not yet been described and that the conservation status of Saguinus species and subspecies should be carefully revised using modern molecular approaches.

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Oysters (Ostreidae) manifest a high degree of phenotypic plasticity, whereby morphology is of limited value for species identification and taxonomy. By using molecular data, the aim was to genetically characterize the species of Crassostrea occurring along the Brazilian coast, and phylogenetically relate these to other Crassostrea from different parts of the world. Sequencing of the partial cytochrome oxidase c subunit I gene (COI), revealed a total of three species of Crassostrea at 16 locations along the Brazilian coast. C. gasar was found from Curuçá (Pará state) to Santos (São Paulo state), and C. rhizophorae from Fortim (Ceará state) to Florianópolis (Santa Catarina state), although small individuals of the latter species were also found at Ajuruteua beach (municipality of Bragança, Pará state). An unidentified Crassostrea species was found only on Canela Island, Bragança. Crassostrea gasar and C. rhizophorae grouped with C. virginica, thereby forming a monophyletic Atlantic group, whereas Crassostrea sp. from Canela Island was shown to be more similar to Indo-Pacific oysters, and either arrived in the Atlantic Ocean before the convergence of the Isthmus of Panama or was accidentally brought to Brazil by ship.

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Four DNA datasets were combined in tandem (6700 bp) and Maximum parsimony and Neighbor-Joining analyses were performed. The results suggest three groups emerging almost at the same time: Atelidae, Pitheciidae and Cebidae. The total analysis strongly supports the monophyly of the Cebidae family, grouping Aotus, Cebus and Saimiri with the small callitrichines. In the callitrichines, the data link Cebuela to Callithrix, place Callimico as a sister group of Callithrix/Cebuella, and show Saguinus to be the earliest offshoot of the callitrichines. In the family Pithecidae, Callicebus is the basal genus. Finally, combined molecular data showed congruent branching in the atelid clade, setting up Alouatta as the basal lineage and Brachyteles-Lagothrix as a sister group and the most derived branch. Two major points remain to be clarified in the platyrrhine phylogeny: (i) what is the exact branching pattern of Aotus, Cebus, Saimiri and the small callitrichines, and (ii), which two of these three lineages, pitheciines, atelines or cebids, are more closely related?

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)