Molecular variability in Brycon cf. pesu Muller and Troschel, 1845 (Characiformes: Characidae) from the Araguaia-Tocantins Basin

Abstract

AbSTRACT. Brycon pesu is a small-sized fish distributed throughout the Amazon and Orinoco Basins and other coastal basins of northeastern South America. Brycon cf. pesu specimens from the Araguaia-Tocantins Basin are currently separated into two morphotypes, Brycon sp1 and Brycon sp2, owing to different coloration of their anal fin. Brycon sp2 has a reddish margin stripe on the anal fin which morphologically distinguishes it from Brycon sp1. In the present research, nuclear and mitochondrial markers were used to test the hypothesis that the Brycon sp1 and Brycon sp2 morphotypes are distinct species. Specimens from the two morphotypes were collected from the Lajeado Hydroelectric Plant and the Palmas River in the AraguaiaTocantins Basin. Thirty-five loci obtained by the amplification of five inter-simple sequence repeat primers were analyzed but no species-specific bands were detected. Electrophoretic profiles obtained from 5S rDNA non-transcribed spacer amplification failed to show any differentiation in morphotypes. These results were corroborated by nucleotide sequence analysis of the mtDNA control region, in which 24 polymorphic nucleotide sites, representing a polymorphism rate of only 5%, were detected. The low rates of polymorphism detected by inter-simple sequence repeat, non-transcribed spacer and mtDNA D-loop markers strongly reject the hypothesis that the two morphotypes Brycon sp1 and Brycon sp2 represent distinct species within Brycon cf. pesu. Further studies are needed to obtain conclusive data on the notion that the coloration of the anal fin is an intraspecific polymorphism, possibly related to environmental factors.

Genetic divergence among invasive and native populations ofPlagioscion squamosissimus(Perciformes, Sciaenidae) in Neotropical regions

“…The 12 nucleotide substitutions in the mtDNA control region of P. squamosissimus clearly indicated that the PI and TO native populations went through independent evolution and became genetically differentiated. The high level of intraspecific genetic similarity (96%) between the PI and TO P. squamosissimus populations resembled levels of genetic similarities among populations of other Neotropical fish species also analysed for polymorphism in the mtDNA control region (Prioli et al , 2002; Oliveira et al , 2006; Panarari‐Antunes et al , 2008). Genetic differentiation based on mtDNA control region polymorphism has been found relatively high among species, including the closely related species Cichla kelberi Kullander & Ferreira 2006 (previously Cichla monoculus Spix & Agassix 1831), Cichla piquiti Kullander & Ferreira (previously Cichla sp.…”

“…The mitochondrial DNA (mtDNA) D‐loop control region is the fastest evolving and the most variable sequence of metazoan DNA. It has been the main molecular marker of choice for analyses of intraspecific genetic variation, including fish species (Panarari‐Antunes et al , 2008; Pie et al , 2009; Antunes et al , 2010; Hirayama et al , 2010; Lo Presti et al , 2010).…”

Genetic variability of brycon orbignyanus (valenciennes, 1850) (characiformes: characidae) in cultivated and natural populations of the upper paraná river, and implications for the conservation of the species

“…Nuclear markers such as RAPD (Random Amplified Polymorphic DNA), and sequences of mitochondrial DNA (mtDNA) have been useful in the studies of the genetic structure of populations, phylogeographic relations and phylogenetic reconstruction in fishes (Sivasundar et al, 2001;Liu et al, 2005;Lage and Kornfield, 2006;Antunes et al, 2010). Molecular studies have been developed with several species of the genus Brycon (Wasko and Galetti, 2002;Barroso et al 2003;Wasko and Galetti, 2003;Wasko et al 2004;Santis et al, 2007;Panarari-Antunes et al, 2008;Antunes et al, 2010). However, there are few genetic studies with B. orbignyanus, and those assessing the genetic diversity of natural populations are needed, so that they can be used in programs of conservation of the species.…”

Scientometrics Analysis on the Use of Molecular Markers in Studies of the Sciaenidae Family (Teleostei: Perciformes).

“…The most frequently used mitochondrial DNA D-loop has been the main molecular marker to analyze genetic variation, including fish species (Panarari-Antunes et al, 2008;Hirayama et al, 2010;Lo Presti et al, 2010).…”