Genetic variability of Hypostomus (Teleostei, Loricariidae) from the Ribeirão Maringá, a stream of the upper Rio Paraná basin, Brazil

Abstract

Hypostomus strigaticeps and two morphotypes of Hypostomus were collected from Ribeirão Maringá, a small tributary of the Rio Pirapó, an effluent of the upper Rio Paraná. The three populations were analyzed by allozyme electrophoresis that allowed the scoring of 25 loci from 14 enzyme systems. Heterozygosity values (H e ) were 0.028 in H. strigaticeps, 0.027 in Hypostomus sp. 1 and zero in Hypostomus sp. 2. Several diagnostic loci and fixed differences were observed for each population at loci Acp-A, Gcdh-A and Mdhp-A. Thus, all populations were genetically distinct, although there were many common alleles. The unbiased genetic identities of Nei (I)

Reproductive strategies and genetic variability in tropical freshwater fish

“…This is surprising, since other cases of absence of genetic variability have been found in two sedentary species, Neoplecostomus paranensis from the upper Paraná River (Zawadzki et al, 2004b) and Hypostomus sp. 2 from the third-order Paraná River tributary Ribeirão Maringá (Paiva et al, 2005). Furthermore, P. maculatus, the other long-distance migratory species analyzed in our study, showed low genetic variability (He = 0.011), contrasting with the value of He = 0.132 estimated for other migratory species such as Prochilodus lineatus (Revaldaves et al, 1997) and Leporinus friderici (Chiari and Sodré, 1999).…”

Genetic variability in three species of Gymnotus Linnaeus, 1758 (Gymnotiformes: Gymnotidae) from Caracu stream of the upper Paraná River basin, Brazil

“…Homozygote excess have also been found in the Hypostomus species from the upper Paraná and Paraguay River basins, which also have sedentary habits (Zawadzki et al, 2002(Zawadzki et al, , 2004Paiva et al, 2005;Renesto et al, 2007) The genetic distance and genetic identity values among the three species of Gymnotus showed that the populations with larger genetic divergence were G. sylvius and G. inaequilabiatus (D = 0.117), and the genetically closest populations were G. inaequilabiatus and G. pantanal (D = 0.051). Nei's genetic distance, D, is claimed to estimate the average number of electrophoretically detectable substitutions per locus and, given certain assumptions, to be linearly proportional to evolutionary time (Thorpe & Solé-Cava, 1994).…”

Short Communication Isolation and characterization of microsatellite markers in the armored catfish Hypostomus gymnorhynchus (Loricariidae)

“…The low polymorphism found for three species of Hypostomus from the Paraná Basin for isozymes (Paiva et al, 2005) and in the present study suggests that it could be a characteristic of the Hypostomus group that deserves an in-depth investigation, including more species and populations.…”