Patrícia Cristina Gomes

Comparación de protocolos de extracción de ADN con muestras de aleta y larva de peces: extracción modificada con cloruro de sodio

N.M. Lopera-Barrero, J.A. Povh, R.P. Ribeiro, P.C. Gomes, C.B. Jacometo, and T. da Silva Lopes. Comparison of DNA extraction protocols of fi sh fi n and larvae samples: modifi ed salt (NaCl) extraction. 2008. Cien. Inv. Agr. 35(1):77-86. The use of appropriate sampling methods, the type of tissue or sample and the use of viable DNA extraction protocols are critical issues in studies based on PCR. In an attempt to identify a simple, reproducible, inexpensive and non-toxic method for obtaining high quality and quantity genomic DNA from fi sh fi n and larvae samples, modifi ed salt extraction protocol and modifi ed phenol-chloroform extraction protocol were compared. The samples obtained from different fi sh species (Brycon orbignyanus, Piaractus mesopotamicus, Oreochromis niloticus, Leporinus elongatus and Prochilodus lineatus) using salt extraction showed good DNA quality and quantity (DNA/RNA relationship 1.8-2.2). These DNA samples were successfully used in the amplifi cation of RAPD (Random Amplifi ed Polymorphic DNA) and microsatellite molecular markers, demonstrating the same effectiveness of this protocol in comparison with modifi ed phenol-chloroform extraction protocol. This DNA extraction procedure constitutes an alternative and effi cient replacement for previous protocols for improving fi sh molecular studies.

Variabilidade genética em tambaquis (Teleostei: Characidae) de diferentes regiões do Brasil

The objective of this study was to evaluate the genetic diversity of four broodstocks of tambaqui (Colossoma macropomum) from different regions of Brazil using RAPD markers. Ten primers were used to analyze 116xa0individuals, collected from fish cultures of three municipalities in Brazil: Urupa, RO; Teixeiropolis, RO; Neopolis, SE; and Sorriso, MT. Differences in the frequencies of 67 fragments were found, with a unique fragment in Sorriso and two in Neopolis. High values of polymorphism (72.92 to 83.33%), Neis genetic diversity (from 0.27 to 0.30) and Shannon index (from 0.39 to 0.45) were observed. Analysis of molecular variance showed that most of the variation is within each broodstock and not among them. The identity and genetic distance among the groups ranged from 0.93 to 0.98 and from 0.02 to 0.07, respectively, with less distance between clusters Urupa x Sorriso and Teixeropolis x Neopolis. Genetic differentiation ranged from low to moderate (Fst = 0.03 to 0.15) and the number of migrants per generation was high (Nm = 5.96 to 24.3) among the groups. Stocks have high variability and low genetic differentiation and distance among them.

Diversidade genética de pacu do Rio Paranapanema e do estoque de um programa de repovoamento

The objective of this work was to study the genetic diversity of pacu samples from the middle Paranapanema River and from the broodstock used in the stock enhancement program of the Aquaculture and Hydrology Station at the Duke Energy Power Plant, by RAPD marker. Fourteen primers were used to analyze 30 individuals captured in the middle Paranapanema River and 29 individuals from the broodstock. The Shannon genetic diversity index and percentage of polymorphic fragments were higher in individuals captured in the Paranapanema River. Genetic similarity was larger in individuals of the broodstock. Results of analysis of molecular variance showed that the major part of the genetic variation is within the groups (84.2%) and not between them (15.8%). The identity and genetic distance among the groups were 0.9517 and 0.0549, respectively. Moderate genetic differentiation (FST = 0.15) and high number of migrants per generation (Nm = 5.33) were observed between the two groups. The genetic diversity was lower in the broodstock than in fish captured in the middle Paranapanema River.

Monitoramento da variabilidade genética de pacu, Piaractus mesopotamicus, do programa de aumento de estoque do rio Paranapanema

Avaliou-se a variabilidade genetica dos estoques de reprodutores e dos peixes jovens de Piaractus mesopotamicus de tres pisciculturas do estado do Parana, utilizadas no programa de aumento de estoque de peixes no rio Paranapanema. Foi utilizado o marcador RAPD para avaliar as amostras do estoque de reprodutores e dos peixes jovens das pisciculturas de Palotina, Cambara e Andira. A porcentagem de fragmentos polimorficos e o indice de diversidade genetica de Shannon dos estoques de reprodutores variaram de 75,0% a 71,4% e de 0,434 a 0,376, respectivamente. Os peixes jovens das pisciculturas apresentaram valores mais elevados para ambos os parâmetros, com excecao da piscicultura de Palotina, na qual o indice de diversidade genetica de Shannon foi semelhante. Os estoques de reprodutores apresentaram alta variabilidade genetica, e esta foi mantida nos peixes jovens.

CARACTERIZACIÓN GENÉTICA DE TRES LÍNEAS DE TILAPIA DEL NILO (OREOCHROMIS NILOTICUS)

Resumen es: EL objetivo de este estudio fue analizar la diversidad genetica de tres lineas de tilapia del Nilo (Oreochromis niloticus), mediante marcadores RAPDs. Se...

Diversidad genética de Piaractus mesopotamicus utilizado en programas de repoblación

Nowadays it has been verified the decrease and the disappearance of many fish species in several aquatic environments in the Brazil. As form of minimizing that impact, stocking programs come being used with more intensity, meantime, little importance has been given to the genetic variability, fundamental parameter for any conservation practices. The objective of this study was to analyze the genetic diversity of Piaractus mesopotamicus stocks used in stocking programs, through the RAPD molecular marker. Sixty broodstocks of two fish farms stations located in the Sapopema (S) and Cambara (C) cities in the Parana State (Brazil) and 30 larvae of the Sapopema offspring (PS) were analyzed. The 10 selected primers yielded 69 fragments of which 62 (89.85%) were polymorphic. Differences (p<0.05) in the frequency of 42 fragments were observed, with four exclusive for the Sapopema stock. The genetic variability results estimated by the percentage of polymorphic fragments (S: 70.15%; PS: 73.13% and C: 77.81%) and for the genetic diversity of Shannon index (S: 0.365; PS: 0.379 and C: 0.468) showed that the genetic variability was maintained in the offspring, due possibly to the good reproductive management. On the other hand, the opposing genetic variability among the two broodstocks indicated a genetic differentiation among them, possibly due to the founder effect. According with the AMOVA, most of the variation is within each stock (62.43%). This result was corroborated with the FST (0.375) values and the effective number of migrants (2.20) that showed a high genetic differentiation and a low gene flow. It was also verified that S and SP were those but similar genetically (genetic identity, IG= 0.851) and that S and C presented less genes in common (IG= 0.786).