Estudo de oito espécies da familia Anostomidae (Pisces, Characiformes) através da análise de RAPD

Random Amplified Polymorphic DNA (RAPD) techniques were applied to eight Anostomidae species to analyze the genetic variability and genetic similarity within and between species. The results obtained were compared to those from isoenzyme analysis executed for many of the species studied. The proportion of polymorphic loci obtained with 10 primers was over 40%, with the exception of Leporinus amblyhynchus. This is especially important since genetic variability is a population feature both for short term fitness of the individual and for the long term survival of populations. Through subsequent analysis of dendrograms it was possible to discriminate the two Schizodon species from those of the genus Leporinus, even though it was impossible to differentiate L. obtusidens and L. elongates. RAPD analysis indicates that the two species are genetically very similar, supported too by isoenzyme dataA técnica de Polimorfismo de DNA Amplificado ao Acaso (RAPD) foi utilizada na análise de oito espécies de peixe da família Anostomidae, com a finalidade de quantificar a variabilidade genética e estimar a similaridade genética dentro e entre essas espécies. Os resultados foram comparados com dados obtidos anteriormente com isoenzimas, para a maioria das espécies analisadas. A proporção de locos polimórficos obtida, com dez primers, está acima de 40 %, exceto para Leporinus amblyhynchus. Esse é um fato importante desde que a existência de variabilidade genética é uma condição importante para a sobrevida das espécies no meio ambiente Com dendrograma obtido, através de análise comparativa, foi possível discriminar as duas espécies de Schizodon daquelas do gênero Leporinus, no entanto não foi possível separar L. obtusidens e L. elongatus. A análise de RAPD indica que essas duas espécies são genéticamante muito similares, conclusão também sustentada por dados de estudos de isoenzima

Genetic variability in five species of Anostomidae (Ostariophysi - Characiformes)

Genetic variability was studied in five fish species (Anostomidae): Schizodon intermedius and S. nasutus and Leporinus friderici, L. elongatus and L. obtusidens, collected at one location on the Tibagi River (Paraná, Brazil). The protein data from seven systems coded collectively for 19 loci in the liver, muscle and heart. Nine of these loci were polymorphic. The estimated proportion of polymorphism loci (<img src="http:/img/fbpe/gmb/v22n4/si_p_.gif" align="absmiddle">) varied from 16.7% in S. intermedius to 36.9% in L. friderici; the mean heterozygosity observed (<img src="http:/img/fbpe/gmb/v22n4/si_h_.gif" alt="si_h_.gif (76 bytes)" align="absmiddle">o) was 0.027 ± 0.015 and 0.109 ± 0.042, respectively. The estimated value of the genetic identity among L. friderici and S. intermedius (0.749) and S. nasutus (0.787) suggested that these are "congeneric" species. Morphological characteristics indicate that these species belong to distinct genera, while isoenzymatic data show that they are very similar at the genetic/biochemical level

Estudo comparativo através de análises de RAPD de seis espécies da família Pimelodidae (Osteichthyes, Siluriformes) do rio Tibagi, Estado do Paraná, Brasil

The genetic similarity of six species from the Pimelodidae family (Osteichthyes, Siluriformes), collected at four sites in the Tibagi River basin, was analyzed using RAPD. RAPD comparative analysis was carried out to observe the degree of genetic similarity among the six species of Pimelodidae. The dendrogram obtained by analysis of the comparative RAPD profiles clearly showed that the individuals investigated from each species clustered together, that is, there was a defined separation among the six species. Two clusters also separated distinctly, one formed by the P. maculatus, P. cf. absconditus, I. labrosus and P. pirinampu (Pimelodinae subfamily) species and the other by the P. aff. avanhandavae and Pimelodella aff. meeki (Heptapterinae subfamily) species. The genetic similarity among these groupings was 0.084.A similaridade genética de seis espécies, pertencentes à família Pimelodidae (Osteichthyes, Siluriformes), coletadas em quatro localidades na bacia do rio Tibagi, foi analisada utilizando-se a técnica de RAPD. A análise comparativa de RAPD foi realizada para observar o grau de similaridade genética entre seis espécies de Pimelodidae. O dendrograma obtido através da análise comparativa dos padrões de RAPD mostrou claramente que os indivíduos estudados de cada uma das espécies se agrupam entre si, ou seja, há uma separação definida entre as seis espécies. Dois agrupamentos foram obtidos, um formado pelas espécies P. maculatus, P. cf. absconditus, I. labrosus e P. pirinampu (Subfamília Pimelodinae), e outro formado pelas espécies P. aff. avanhandavae e Pimelodella aff. meeki (subfamília Heptapterinae). A similaridade genética entre esses agrupamentos foi de 0.084

Population structure analysis of Pimelodus maculatus (Pisces, Siluriformes) from the Tietê and Paranapanema Rivers (Brazil)

Pimelodus maculatus populations from the Tietê and Paranapanema rivers were sampled and had their genetic structure analyzed by using RAPD markers, with the aim of contributing to future conservation studies. The proportion of polymorphic loci was greater than 50% in the populations of both rivers. Genetic diversity data showed that, in spite of its nine hydroelectric plants, the Tietê river population was genetically homogeneous, whereas the Paranapanema river population was structured. This might be due to the presence of high waterfalls distributed all along its course. These data may serve as indicators for future conservation studies on the Tietê and Paranapanema rivers