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

Abstract

Resumo -O objetivo deste trabalho foi avaliar a diversidade genética em quatro estoques de tambaquis (Colossoma macropomum) de diferentes regiões do Brasil, por meio de marcador RAPD. Foram utilizados 10 iniciadores para analisar 116 indivíduos, coletados de pisciculturas nos municípios de Urupá, RO, Teixeirópolis, RO, Neópolis, SE e Sorriso, MT. Foram encontradas diferenças nas frequências de 67 fragmentos, com um fragmento exclusivo em Sorriso e dois em Neópolis. Observaram-se altos valores de polimorfismo (72,92 a 83,33%), diversidade genética de Nei (0,27 a 0,30) e índice de Shannon (0,39 a 0,45). A análise da variância molecular, demonstrou que a maior parte da variação está dentro de cada estoque e não entre os estoques.A identidade e a distância genética entre os agrupamentos variou de 0,93 a 0,98 e 0,02 a 0,07, respectivamente, com menos distância entre os agrupamentos Urupá x Sorriso e entre Teixerópolis x Neópolis. A diferenciação genética variou de baixa a moderada (F st = 0,03 a 0,15) e o número de migrantes por geração foi alto (Nm = 5,96 a 24,3), entre os agrupamentos. Os estoques apresentam alta variabilidade e baixa diferenciação e distância genética entre si.Termos para indexação: Colossoma macropomum, diversidade genética, RAPD. Genetic variability of tambaqui (Teleostei: Characidae) from different regions of BrazilAbstract -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 116 individuals, collected from fish cultures of three municipalities in Brazil: Urupá, RO; Teixeirópolis, RO; Neópolis, SE; and Sorriso, MT. Differences in the frequencies of 67 fragments were found, with a unique fragment in Sorriso and two in Neópolis. High values of polymorphism (72.92 to 83.33%), Nei's 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 Urupá x Sorriso and Teixerópolis x Neópolis. Genetic differentiation ranged from low to moderate (F st = 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.

Impacts of stocking on the genetic diversity of Colossoma macropomum in central Amazon, Brazil

“…The results partially agree with those reported by Jacometo et al (2010), who found high genetic variability in tambaqui broodstocks from Northern Brazil, but with low intergroup differentiation and genetic distance. Endogamy is one of the main causes of reduced genetic variability and differentiation among broodstock individuals and populations (Taniguchi, 2003).…”

“…According to Nei's (1973) measure of genetic diversity, average heterozygosity of the three broodstocks was 0.336, with the lowest estimate found for Balbina stock (0.283). Similarly, estimates of genetic diversity were close to those described for tambaqui broodstocks analyzed using RAPD markers (Jacometo et al, 2010). Variations in estimated genetic diversity of the samples may be attributed to the history and level of genetic management of the stocks, although this has been scarcely documented.…”

“…In previous studies using RAPD, the Shannon index for broodstocks in Rondônia state ranged from 0.44 to 0.46 (Lopes et al, 2009), and in four stocks from different regions of Brazil it ranged from 0.39 to 0.45 (Jacometo et al, 2010). According to Nei's (1973) measure of genetic diversity, average heterozygosity of the three broodstocks was 0.336, with the lowest estimate found for Balbina stock (0.283).…”

“…In the present study, the 10 ISSR primers selected showed optimal efficiency, producing polymorphic patterns above 88.2% for the three broodstocks studied. Using the same class of markers and number of primers, Jacometo et al (2010) obtained a lower proportion of random amplified polymorphic DNA (RAPD) polymorphisms for tambaquis, ranging from 72.92 to 83.33%.…”

Seeds of sacha inchi (Plukenetia volubilis, Euphorbiaceae) as a feed ingredient for juvenile tambaqui, Colossoma macropomum, and matrinxã, Brycon amazonicus (Characidae)

“…Tambaqui is naturally resilient, tolerates low concentrations of dissolved oxygen and is resistant to sudden changes in pH (Aride et al 2007;Silva et al 2007;Dairiki and Silva 2011). About 80% of tambaqui currently commercialized is produced in captivity (Jacometo et al 2010). The production of matrinxã production was of 9,366,203 tons in 20159,366,203 tons in (IBGE 2015.…”