Genetic diversity of the species Cnesterodon hypselurus (Cyprinodontiformes: Poeciliidae) in Cinzas River basin: new record and headwater capture evidences

Cnesterodon hypselurus is a small fish that has a restricted distribution in southern Brazil, including headwaters of the Tibagi and Itararé river basins (Upper Paraná River). This study reported C. hypselurus in a headwater of Cinzas River basin, where there were no previous records of this species, and employed microsatellite loci and mitochondrial haplotypes in a population genetic analysis. A total of 57 specimens was analyzed, including 30 from Cinzas River basin, 25 from Itararé River basin and two from Tibagi River basin. Results indicated low genetic diversity levels (HE = 0.334 and h = 0.246) for the sample from Cinzas River, suggesting reflections of a founder effect after the species had dispersed from one watershed to another, possibly by headwater captures. Since different populations were detected between the Cinzas and Itararé rivers (DEST = 0.248, P-value < 0.05) and other occurrence sites are still unknown in the Cinzas River basin, the data herein have great relevance and should be taken into account in future management and conservation actions, as well as in evolutionary studies of C. hypselurus.(AU)

Cnesterodon hypselurus é um pequeno peixe que possui distribuição restrita no sul do Brasil, incluindo cabeceiras das bacias dos rios Tibagi e Itararé (alto rio Paraná). Este estudo reportou C. hypselurus na cabeceira da bacia do rio das Cinzas, onde não havia registros prévios desta espécie, e empregou locos microssatélites e haplótipos mitocondriais em uma análise genética de populações. Um total de 57 espécimes foi analisado, incluindo 30 do rio das Cinzas, 25 da bacia do rio Itararé e dois da bacia do rio Tibagi. Os resultados indicaram baixos níveis de diversidade genética (HE = 0,334 e h = 0,246) para a amostra do rio das Cinzas, sugerindo reflexos de um efeito fundador após a espécie ter dispersado de uma bacia para a outra, possivelmente a partir de captura de cabeceiras. Uma vez que diferentes populações foram detectadas entre os rios das Cinzas e Itararé (DEST = 0,248, valor de P < 0,05) e que outros pontos de ocorrência ainda são desconhecidos na bacia do rio das Cinzas, os dados do presente estudo mostram grande relevância e deveriam ser considerados em futuras ações de manejo e conservação, bem como em estudos evolutivos de C. hypselurus.(AU)

Diagnostic locus for identification of silverside hybrids (Odontesthes humensis and Odontesthes bonariensis) in a natural population / Locus diagnóstico para identificação de híbridos de peixe-rei (Odontesthes humensis and Odontesthes bonariensis) em população natural

Hybridization is a natural phenomenon that occurs more often in fish than in other vertebrates. The use of nuclear and mitochondrial molecular markers provides valuable results in the detection of these events. The aim of this study was to investigate the occurrence of interspecific hybrids in natural populations of silverside. The samples of Odontesthes humensis, Odontesthes bonariensis, and indivi-duals that were morphologically different from pure species were collected in the Mangueira lagoon, located in southern Brazil. Result: Six tetranucleotide microsatellite loci were synthesized and tested. The UFPEL_OH3 locus proved to be diagnostic for the detection of silverside hybrids, and it was possi-ble to distinguish between pure and hybrid species. The mitochondrial marker gene cytb synthesized from conserved Odontesthes sequences in the GenBank genetic database showed no differences in the genetic sequence of the samples, needing further studies to confirm the hypothesis.(AU)

A hibridação é um fenômeno natural que ocorre mais frequentemente em peixes do que em outros vertebrados. Para detectá-la, são utilizados marcadores moleculares nucleares e mitocondriais, os quais fornecem resultados valiosos. O objetivo deste estudo foi investigar a ocorrência de híbridos in-terespecíficos em populações naturais de peixe-rei. As amostras de Odontesthes humensis, Odontesthes bonariensis e de indivíduos morfologicamente diferentes das espécies puras foram coletadas na lagoa Mangueira, localizada no Sul do Brasil. Foram sintetizados e testados seis loci microssatélites tetranu-cleotídeos. O locus UFPEL_OH3 mostrou-se um diagnóstico para detectar híbridos de peixe-rei, pos-sibilitando a distinção de espécies puras de híbridas. O marcador mitocondrial gene cytb, sintetizado com base nas sequências conservadas de Odontesthes no banco de dados genéticos do GenBank, não apresentou diferenças na sequência genética das amostras, portanto, são necessários mais estudos para confirmar a hipótese de hibridação.(AU)

Outbreak of toxoplasmosis associated with muscular lesions in finishing pigs caused by an atypical Toxoplasma gondii genotype / Surto de toxoplasmose associado a lesões musculares em suínos de terminação causado por um genótipo atípico de T. gondii

Toxoplasma gondii infections are usually asymptomatic in pigs, and an acute clinical disease is rare in this host. This study aimed to determine the pathological and molecular aspects of an outbreak of fatal systemic toxoplasmosis in finishing pigs in Brazil. The outbreak occurred on a commercial finishing pig farm in the state of Santa Catarina in southern Brazil. The farm had 1500 pigs and 3.8% of mortality rate during the outbreak. The pigs had fever, anorexia, apathy, and locomotor deficits. Seven pigs were necropsied. Gross findings included multifocal to coalescent pale areas in skeletal muscles, lymphadenomegaly, hepatosplenomegaly, and non-colapsed lungs. The histological findings included granulomatous lymphadenitis, hepatitis and splenitis, necrotizing myositis, and lymphoplasmacytic interstitial pneumonia. Lung and liver lesions were occasionally accompanied by T. gondii parasitic structures. Positive immunolabeling for T. gondii tachyzoites and encysted bradyzoites was detected in all examined pigs. PCR-RFLP (11 markers) and microsatellite analysis (15 markers) identified the non-archetypal genotype #278 in pigs. This is the first report of systemic toxoplasmosis in pigs with muscle lesions and additionally shows the diversity of disease-causing T. gondii genotypes circulating in animals in Brazil.(AU)

As infecções por Toxoplasma gondii são geralmente assintomáticas em suínos, e uma doença clínica aguda é rara nessa espécie. Este estudo teve como objetivo determinar os aspectos patológicos e moleculares de um surto de toxoplasmose sistêmica fatal em suínos em terminação no Brasil. O surto ocorreu em uma granja comercial de suínos em terminação no estado de Santa Catarina, no sul do Brasil. A granja tinha 1500 suínos e a taxa de mortalidade durante o surto foi de 3,8%. Os suínos apresentaram febre, anorexia, apatia e déficits locomotores. Sete suínos foram necropsiados. Os achados macroscópicos incluíram áreas pálidas multifocais a coalescentes nos músculos esqueléticos, linfadenomegalia, hepatoesplenomegalia e pulmões não colapsados. Os achados histológicos incluíram linfadenite, hepatite, esplenite granulomatosa e miosite necrosante, assim como pneumonia intersticial linfoplasmocítica. Lesões pulmonares e hepáticas foram ocasionalmente acompanhadas por estruturas parasitárias de T. gondii. A imunomarcação positiva para taquizoítos e bradizoítos encistados de T. gondii foi observada em todos os suínos examinados. PCR-RFLP (11 marcadores) e análise de microssatélites (15 marcadores) identificaram o genótipo não arquetípico #278 em suínos. Este é o primeiro relato de toxoplasmose sistêmica em suínos com lesões musculares e, adicionalmente, demonstra a diversidade de genótipos de T. gondii causadores de doenças circulantes em animais no Brasil.(AU)

Microsatellite Polymorphism and Prokaryotic Expression of Mef2d in Xingyi Duck

Myocyte enhancer factor 2D (MEF2D) are members of the myocyte enhancer factor 2 (MEF2), a supergene family and are thought to be related to the development and regeneration of skeletal muscle. We selected a microsatellite locus located in the MEF2D gene to study the slaughter characteristics of Xingyi duck and discuss whether the locus could be used as a molecular genetic marker associated with the slaughter characteristics. To further study the function of this gene, we cloned the coding region of the MEF2D gene and expressed it in the prokaryotic expression system. We amplified exon 9 of MEF2D gene by PCR and analyzed after sequencing. The entire CDS region was amplified by RT-PCR. The prokaryotic expression vector was constructed by double enzyme digestion. Results showed that there was a significant correlation between the microsatellite polymorphism of exon 9 of the MEF2D gene and the eviscerated weight rate of Xingyi duck (p<0.05). The eviscerated weight rate of the aa (40/40) genotype was significantly higher than that of the ab (40/49) genotype. The CDS region of the MEF2D gene was cloned with a length of 1557 bp. The prokaryotic expression vector pET32a(+)-MEF2D was constructed. The results provide a foundation for future studies examining the function of the MEF2D.(AU)

Microsatellite Polymorphism and Prokaryotic Expression of Mef2d in Xingyi Duck

Myocyte enhancer factor 2D (MEF2D) are members of the myocyte enhancer factor 2 (MEF2), a supergene family and are thought to be related to the development and regeneration of skeletal muscle. We selected a microsatellite locus located in the MEF2D gene to study the slaughter characteristics of Xingyi duck and discuss whether the locus could be used as a molecular genetic marker associated with the slaughter characteristics. To further study the function of this gene, we cloned the coding region of the MEF2D gene and expressed it in the prokaryotic expression system. We amplified exon 9 of MEF2D gene by PCR and analyzed after sequencing. The entire CDS region was amplified by RT-PCR. The prokaryotic expression vector was constructed by double enzyme digestion. Results showed that there was a significant correlation between the microsatellite polymorphism of exon 9 of the MEF2D gene and the eviscerated weight rate of Xingyi duck (p<0.05). The eviscerated weight rate of the aa (40/40) genotype was significantly higher than that of the ab (40/49) genotype. The CDS region of the MEF2D gene was cloned with a length of 1557 bp. The prokaryotic expression vector pET32a(+)-MEF2D was constructed. The results provide a foundation for future studies examining the function of the MEF2D.

Genetic diversity assessment for the vulnerable migratory cownose ray Rhinoptera bonasus (Myliobatiformes: Rhinopteridae) from the southwestern Atlantic Ocean

ABSTRACT Rhinoptera bonasus is a bento-pelagic and highly migratory species occurring from southern United States to northern Argentina. Due to overfishing effects, R. bonasus is currently at risk, classified by the IUCN Red List as vulnerable. Considering the lack of molecular data available for R. bonasus, this study aimed to describe the genetic variability and population structure of specimens sampled from three Brazilian coast ecoregions (Amazon ecoregion, Pará; Northeastern ecoregion, Pernambuco and Southeastern ecoregion, Rio de Janeiro, São Paulo and Santa Catarina), through five polymorphic microsatellite markers. Here testing the panmixia hypothesis for Brazilian ecoregions and test natal philopathy. A total of 69 analyzed specimens revealed individual and significant genetic differentiation between the sampled locations. ST (0.12), PCA, DAPC and Bayesian analyses of the genetic population structure revealed at least two distinct genetic R. bonasus groupings. IBD tests were significant, indicating a correlation between genetic and geographical distance among populations, which can be explained by reproductive philopatric behavior. Philopatric behavior associated with R. bonasus mobility may influence the differentiation values observed for all loci in the investigated samples.

RESUMO Rhinoptera bonasus é uma espécie bento-pelágica e altamente migratória, que ocorre do sul dos Estados Unidos ao norte da Argentina. Devido aos efeitos da sobrepesca, R. bonasus está atualmente em risco, classificada pela Lista Vermelha da IUCN como vulnerável. Considerando a falta de dados moleculares disponíveis para R. bonasus, este estudo teve como objetivo descrever a variabilidade genética e estrutura populacional de espécimes amostrados em três ecorregiões do litoral brasileiro (Ecorregião Amazônica, Pará; Ecorregião Nordeste, Pernambuco e Ecorregião Sudeste, Rio de Janeiro, São Paulo e Santa Catarina), por meio de cinco marcadores microssatélites polimórficos. Assim, testaremos as hipóteses de panmixia e filopatria natal. Um total de 69 espécimes analisados revelou diferenciação genética individual e significativa entre os locais amostrados. As análises de ST (0,12), PCA, DAPC e Bayesiana revelaram pelo menos dois agrupamentos genéticos distintos de R. bonasus. Os testes de IBD foram significativos, indicando uma correlação entre a distância genética e geográfica entre as populações, o que pode ser explicado pelo comportamento filopátrico reprodutivo. O comportamento filopátrico associado à mobilidade de R. bonasus pode influenciar os valores de diferenciação observados para todos os loci nas amostras investigadas.

A lima bean core collection based on molecular markers

Some germplasm collections have a high number of accessions, which makes it difficult to explore the genetic variability present in the germplasm bank due to the redundancy and the difficulty of detailed analysis of all conserved accessions. Therefore, our study aimed to analyze the genetic diversity of 153 lima bean (Phaseolus lunatus) accessions for the purpose of constructing a core collection. Eleven SSRs were used for this purpose. The 153 lima bean accessions can be represented by low redundancy using a minimum of 34 accessions, thus representing 22 % of the size of the entire germplasm bank. The core collection had a higher Shannon diversity index and expected heterozygosity (1.906 and 0.811, respectively) than those presented by the entire germplasm bank (1.605 and 0.713, respectively), indicating a higher polymorphism of the representative cultivars in relation to the entire collection. The accessions selected for the core collection may be used in future studies of genome association as well as in genetic crosses in breeding programs aimed at developing improved cultivars with high genetic diversity which can meet current and future market needs.

Interactions Between Non-Allelic Loci and Their Effects on Categorized Meat Performance Traits in Ducks

Traits associated with meat performance are characterized by a complex inheritance model, including the effects of non-allelic interactions. The aim of this study was to estimate the significance of non-allelic interactions between pairs of loci in each of two alternative groups based on four important performance traits of ducks: body weight (BW), carcass yield calculated as the ratio of carcass weight to body weight (CY), breast and leg muscle yield as a fraction of carcass weight (BL-CW), and skin weight and abdominal fat, again as a fraction of carcass weight (SF-CW). The experimental material was based on an F2 cross between two parental lines: A-55 (Polish Peking) and GL-30 (French Peking). In total, 368 individuals were recorded. All of the birds (including parents and F1) were genotyped for 23 polymorphic microsatellite loci. Entropy was taken as a measure of interaction between pairs of loci, and the chi-square test was used to verify significance. In total, 253 pairs of loci were analyzed in both categories of each of the four traits. Statistically significant interactions were obtained for each trait. However, it was observed that some of the loci showed a greater tendency to have significant opposite interactions for alternative categories of the same trait. The results indicate the dependence of the recombination rate within pairs of loci on the level of each of the four traits.(AU)

A lima bean core collection based on molecular markers

Some germplasm collections have a high number of accessions, which makes it difficult to explore the genetic variability present in the germplasm bank due to the redundancy and the difficulty of detailed analysis of all conserved accessions. Therefore, our study aimed to analyze the genetic diversity of 153 lima bean (Phaseolus lunatus) accessions for the purpose of constructing a core collection. Eleven SSRs were used for this purpose. The 153 lima bean accessions can be represented by low redundancy using a minimum of 34 accessions, thus representing 22 % of the size of the entire germplasm bank. The core collection had a higher Shannon diversity index and expected heterozygosity (1.906 and 0.811, respectively) than those presented by the entire germplasm bank (1.605 and 0.713, respectively), indicating a higher polymorphism of the representative cultivars in relation to the entire collection. The accessions selected for the core collection may be used in future studies of genome association as well as in genetic crosses in breeding programs aimed at developing improved cultivars with high genetic diversity which can meet current and future market needs.(AU)

Interactions Between Non-Allelic Loci and Their Effects on Categorized Meat Performance Traits in Ducks

Traits associated with meat performance are characterized by a complex inheritance model, including the effects of non-allelic interactions. The aim of this study was to estimate the significance of non-allelic interactions between pairs of loci in each of two alternative groups based on four important performance traits of ducks: body weight (BW), carcass yield calculated as the ratio of carcass weight to body weight (CY), breast and leg muscle yield as a fraction of carcass weight (BL-CW), and skin weight and abdominal fat, again as a fraction of carcass weight (SF-CW). The experimental material was based on an F2 cross between two parental lines: A-55 (Polish Peking) and GL-30 (French Peking). In total, 368 individuals were recorded. All of the birds (including parents and F1) were genotyped for 23 polymorphic microsatellite loci. Entropy was taken as a measure of interaction between pairs of loci, and the chi-square test was used to verify significance. In total, 253 pairs of loci were analyzed in both categories of each of the four traits. Statistically significant interactions were obtained for each trait. However, it was observed that some of the loci showed a greater tendency to have significant opposite interactions for alternative categories of the same trait. The results indicate the dependence of the recombination rate within pairs of loci on the level of each of the four traits.