Characterization of gene polymorphisms related to immune system physiology in Mangalarga horses / Caracterização de polimorfismos gênicos relacionados à fisiologia do sistema imune em equinos da raça Mangalarga

The objectives of this study were to standardize a PCR-RFLP genotyping method for the AY_731081:g.1900T>C SNP of the equine CD14 gene, and to characterize this SNP and two other polymorphisms (AY_005808: c.1530A>G of the TLR4 gene and AX_463789: g.133T>C of the Cε gene) in Mangalarga horses, in order to contribute to future studies investigating the association between DNA markers and traits related to immune system physiology in this breed. A total of 151 Mangalarga horses of both sexes and variable ages, representative of the population of São Paulo State, were used. PCR-RFLP was found to be adequate for genotyping of the AY_731081: g.1900T>C SNP of the equine CD14 gene. However, this polymorphism is probably not present in Mangalarga horses, thus impairing association studies using this marker in the breed. The population genetic parameters obtained for the TLR4 AY_005808:c.1530A>G and Cε AX_463789:g.133T>C polymorphisms suggest the use of these markers in association studies with immune system-related traits in Mangalarga horses.

Os objetivos deste trabalho foram a padronização da metodologia PCR-RFLP para genotipagem do SNP AY_731081:g.1900T>C do gene CD14 equino, bem como a caracterização em equinos da raça brasileira Mangalarga deste e de outros dois polimorfismos, o AY_005808: c.1530A>G do TLR4 e o AX_463789: g.133T>C do Cε, a fim de promover o embasamento necessário para futuras pesquisas visando à associação entre marcadores de DNA e características relacionadas à fisiologia do sistema imune na raça. Para tanto, foram utilizados 151 animais Mangalarga, de ambos os sexos e de idades variadas, representativos da população do estado de São Paulo. O método de PCR-RFLP mostrou-se adequado para a genotipagem do SNP AY_731081: g.1900T>C do gene CD14 equino. Entretanto, tal polimorfismo provavelmente não ocorre em equinos Mangalarga, impossibilitando estudos de associação com o marcador na raça. Os parâmetros genético-populacionais obtidos para os polimorfismos AY_005808:c.1530A>G do gene TLR4 e o AX_463789:g.133T>C do gene Cε demonstraram a possibilidade de realização de pesquisas.

Mitochondrial D-loop nucleotide diversity in Astyanax (Osteichthyes, Characidae) from the upper Paraná and upper Paraguay River basins.

The morphological discrimination between the species Astyanax altiparanae and A. asuncionensis of the upper Paraná River and Paraguay River basins, respectively, has always been difficult. Two D-loop haplogroups of A. altiparanae are known, one with the presence (AltoPR) or the absence (AltoPR-D) of a 32-bp block similar to that in A. asuncionensis. We examined these samples to characterize A. altiparanae and verify whether A. asuncionensis occurred in the upper Paraná River prior to the submergence of the Sete Quedas Falls when Itaipu reservoir was impounded. D-loop sequences were analyzed in A. altiparanae of the upper Paraná and Iguaçu Rivers and those of A. asuncionensis of the upper Paraguay River. The haplogroup AltoPR was found at all sites of the upper Paraná and Iguaçu Rivers, whereas AltoPR-D occurred in the Itaipu reservoir, floodplain and in the Tietê and Grande Rivers. Two haplogroups of A. asuncionensis were identified and both did not have the 32-bp block. However, AltoPR and AltoPR-D differed from one another in 5.1% of their bases and between 8.9 and 12.5% with regard to the haplogroups of the upper Paraguay basin. Further, AltoPR-D occurred in the Grande River upstream the Marimbondo Falls and other older reservoirs than Itaipu. The results reject the hypothesis of the establishment of A. asuncionensis and suggest that the haplogroup AltoPR-D existed in the upper Paraná River before the impounding of the Itaipu reservoir. Moreover, morphological similarity and high genetic variation within the altiparanae/asuncionensis group suggest the existence of a cryptic species complex.

Molecular differentiation of species of the genus Zungaro (Siluriformes, Pimelodidae) from the Amazon and Paraná-Paraguay River basins in Brazil.

Fish species of the Zungaro genus (Siluriformes, Pimelodidae) are amongst the largest migratory fish in Latin America and have considerable economic importance for commercial fishing in Brazil. However, natural populations of this large catfish are experiencing a severe decline. There are significant taxonomical inconsistencies for this fish. Two geographically separated species of the fish were initially described, one endemic in the Amazon and another in the Paraná-Paraguay River basins. A taxonomic review had recently proposed that there is only one Zungaro species in Brazil, based on morphological data. We made a molecular study of Zungaro populations in an attempt to solve taxonomical inconsistencies and to analyze genetic diversity in natural populations of this genus. We analyzed two regions of the mitochondrial DNA (the control region and the ATPase 6 gene region) of individuals sampled from the Paraná-Paraguay River and Amazon River basins. Analyses based on p-distances and maximum likelihood phylogenetic models showed a genetic difference between populations corresponding to different species. Genetic differentiation between Zungaro populations was at the same level as that observed between other Siluriformes species, using the same DNA sequences. We conclude that Zungaro species of the Paraná-Paraguay River basin do not belong to the same species found in the Amazon basin. This finding has a significant implication for conservation of this fish, given that populations are disappearing at a high rate in the Paraná-Paraguay River basin, mainly due to impoundments.

Diversidade genética entre três linhagens de codorna selecionadas para produção de ovos / Genetic diversity among three lineages of quail, selected for egg production

A diversidade genética entre três linhagens de codorna (Coturnix japônica) foi avaliada utilizando-se a técnica de random amplified polymorphic DNA (RAPD). As linhagens selecionadas para produção de ovos foram identificadas como amarela, azul e vermelha por meio de anilhas no pé esquerdo. Seis primers de RAPD amplificaram 55 loci, os quais geraram padrão de bandas intensa e reproduzível em gel de agarose. Os resultados indicaram polimorfismos dentro e entre as linhagens. A similaridade de Jaccard média e o índice de diversidade Shannon revelaram alta diversidade dentro das linhagens de codornas. O teste de Mantel por meio do algoritmo unweighted pair-group method using arithmetic average (UPGMA) e a dispersão de coordenadas principais indicaram diferenciação genética significativa, embora em baixo nível. Os resultados sugerem que a diversidade genética dentro e entre as linhagens de codornas da Universidade Estadual de Maringá são promissoras para uso em programas de melhoramento.

The genetic diversity among three lineages of quail (Coturnix japonica) was evaluated by the random amplified polymorphic DNA (RAPD) technique. The lineages were selected for egg production and identified with a yellow, blue, or red ring fasten on their left foot. Six selected RAPD primers amplified 55 loci, which generated intense and reproducible bands on agarose gel. The results indicated polymorphism within and among the lineages. The Jaccard similarity average and the Shannon diversity index revealed high diversity values within the quail lineages. The Mantel test, unweighted pair-group method using arithmetic average (UPGMA) algorithm and dispersion of principal coordinates indicated significant genetic differentiation, although at low levels. Overall, the results suggest that the genetic diversity within and among the quail lineags from the State Universidade Estadual de Maringá are promising for use in breeding programs.

Molecular characterization and phylogenetic relationships among species of the genus Brycon (Characiformes: Characidae) from four hydrographic basins in Brazil.

Brycon is one of the main genera of Neotropical freshwater fish. In Brazil, Brycon species have been found in many hydrographic basins, such as the Amazon, Paraná, Paraguay, and Araguaia-Tocantins basins. We examined the phylogenetic relationships among the species Brycon orbignyanus, B. hilarii, B. cf. pesu, B. cephalus, B. falcatus, and B. gouldingi, using mitochondrial and nuclear molecular markers. Specimens of B. orbignyanus were collected in the Paraná River. Specimens of B. hilarii were collected in the Manso River. Specimens of B. cephalus were obtained from a fish farm, and specimens of B. cf. pesu, B. falcatus and B. gouldingi were sampled in the Araguaia-Tocantins basin. DNA extraction was carried out using the phenol/chloroform method. Molecular polymorphism studies of Brycon species were carried out with the inter-simple sequence repeat (ISSR) technique, using the total DNA of six specimens of each species. In DNA amplification of B. cf. pesu, eight specimens were used. The partial sequence of mitochondrial cytochrome b was amplified by PCR. The PCR products were used directly in sequencing reactions. Each ISSR primer produced from 7 to 14 scorable and reproducible bands. The (GGAC)(3)A and (GGAC)(3)C primers produced the greatest number of species-specific bands. A 264-bp fragment, corresponding to the partial region of mitochondrial DNA cytochrome b, was sequenced and used for analysis. According to the phylogenetic tree obtained from the data, these Brycon species can be divided into two clades: one comprised only B. cf. pesu, and the second comprised the remaining Brycon species. We conclude that ISSR primers can be used for the identification of species-specific bands in fish, such as Brycon spp.

Genetic divergence between Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Siluriformes: Pimelodidae) in the Paraná River Basin.

Pseudoplatystoma corruscans (Spix and Agassiz, 1829) and Pseudoplatystoma reticulatum (Eingenmann and Eigenmann, 1889) are large migratory catfishes of high biological importance and great commercial value in South America. Because fertile crossbreeds can be artificially produced in hatcheries, a high genetic proximity between these two Pimelodidae species is conceivable. Possible escape of crossbred specimens from pisciculture stations is a serious environmental concern. Despite their importance, knowledge of P. corruscans and P. reticulatum biology, ecology, population diversity and genetics is limited. In the present work, the genetic divergence between P. corruscans and P. reticulatum populations from the Paraná River Basin was analyzed on the basis of polymorphisms in ISSR fragments and in the hypervariable sequence of the mitochondrial DNA (mtDNA) control region. Estimates of intraspecific haplotype (h > 0.5) and nucleotide diversities (pi < 0.01) indicate that P. corruscans and P. reticulatum have survived a historical population decline, followed by a demographic expansion. The interspecific polymorphisms within the mtDNA control region and ISSR fragments were suitable as diagnostic molecular markers and could be used to discriminate the two species. A unique Pseudoplatystoma specimen, captured in the Upper Paraná River Floodplain, was identified by these DNA diagnostic markers as a hybrid P. reticulatum x P. corruscans, which possibly escaped from pisciculture. The integrity of the natural population of P. corruscans in the Upper Paraná River is at risk of genetic introgression or homogenization due to the presence of hybrids and the transposition of P. reticulatum upstream through the Canal da Piracema at Itaipu Dam. Data presented herein improve the understanding of the genetic relatedness between P. corruscans and P. reticulatum and represent potential tools for future programs of conservation and surveillance of genetic introgression events and the genetic integrity of these populations.

Genetic divergence between Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Siluriformes: Pimelodidae) in the Paraná River Basin / Divergência genética entre Pseudoplatystoma corruscans e Pseudoplatystoma reticulatum (Pisces; Siluriformes) da Bacia do Rio Paraná

Pseudoplatystoma corruscans (Spix and Agassiz, 1829) and Pseudoplatystoma reticulatum (Eingenmann and Eigenmann, 1889) are large migratory catfishes of high biological importance and great commercial value in South America. Because fertile crossbreeds can be artificially produced in hatcheries, a high genetic proximity between these two Pimelodidae species is conceivable. Possible escape of crossbred specimens from pisciculture stations is a serious environmental concern. Despite their importance, knowledge of P. corruscans and P. reticulatum biology, ecology, population diversity and genetics is limited. In the present work, the genetic divergence between P. corruscans and P. reticulatum populations from the Paraná River Basin was analyzed on the basis of polymorphisms in ISSR fragments and in the hypervariable sequence of the mitochondrial DNA (mtDNA) control region. Estimates of intraspecific haplotype (h > 0.5) and nucleotide diversities (π < 0.01) indicate that P. corruscans and P. reticulatum have survived a historical population decline, followed by a demographic expansion. The interspecific polymorphisms within the mtDNA control region and ISSR fragments were suitable as diagnostic molecular markers and could be used to discriminate the two species. A unique Pseudoplatystoma specimen, captured in the Upper Paraná River Floodplain, was identified by these DNA diagnostic markers as a hybrid P. reticulatum x P. corruscans, which possibly escaped from pisciculture. The integrity of the natural population of P. corruscans in the Upper Paraná River is at risk of genetic introgression or homogenization due to the presence of hybrids and the transposition of P. reticulatum upstream through the Canal da Piracema at Itaipu Dam. Data presented herein improve the understanding of the genetic relatedness between P. corruscans and P. reticulatum and represent potential tools for future programs of conservation and surveillance of genetic ...

Pseudoplatystoma corruscans Spix e Agassiz, 1829 e Pseudoplatystoma reticulatum Eigenmann e Eigenmann, 1889 são peixes migratórios de grande porte, com alta importância biológica e elevado valor comercial na América do Sul. Híbridos férteis são obtidos em cativeiro e, portanto, é esperada alta proximidade genética entre essas duas espécies de Pimelodidae. Escapes de espécimes híbridos a partir de estações de piscicultura representam um sério problema ambiental. Apesar da sua importância, conhecimentos sobre a biologia, ecologia, diversidade de populações e genética de P. corruscans e P. reticulatum são escassos. No presente trabalho, foi avaliada a divergência genética entre P. corruscans e P. reticulatum da Bacia do Rio Paraná, com base em fragmentos ISSR e na seqüência D-loop do DNA mitocondrial (mtDNA). As estimativas das diversidades intra-específicas haplotípica (h > 0,5) e nucleotídica (π < 0,01) evidenciaram que P. corruscans e P. reticulatum sobreviveram a um declínio populacional histórico, seguido de expansão demográfica. Os polimorfismos interespecíficos no mtDNA e nos fragmentos ISSR foram eficientes para diagnósticos e discriminaram as duas espécies. Um espécime de Pseudoplatystoma capturado na planície de inundação do Alto Rio Paraná foi identificado com esses marcadores moleculares como híbrido P. reticulatum x P. corruscans, que possivelmente escapou de psicicultura. A integridade da população de P. corruscans no Alto Rio Paraná está ameaçada, por introgressão ou homogeneização genética, pela presença de híbridos e pela transposição para montante de P. reticulatum através do Canal da Piracema em Itaipu. Os dados apresentados constituem um avanço na compreensão do parentesco entre P. corruscans e P. reticulatum e representam ferramentas em potencial para programas de conservação biológica, incluindo o monitoramento de introgressão e de integridade genética das populações.