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

Abstract

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.

Genetic analysis of five sedentary fish species in middle Laranjinha River (upper Paraná River basin): A case study

“…The highestP and H E values were observed in A. altiparanae and the lowest values in L. amblyrhynchus (Table 2). All levels of genetic diversity in the populations studied here were evaluated as satisfactory compared to previously reported data (Chiari and Sodré, 2001;Almeida et al, 2003;Leuzzi et al, 2004;Pamponet et al, 2008). …”

“…Previous studies using RAPD reported the following values ofP: Schizodon intermedius 45.5%, Schizodon nasutus 41.4%, Leporinus amblyrhynchus 29.3%, Leporinus friderici 46.3%, Leporinus striatus 41%, Leporinus octofasciatus 55.1%, Leporinus elongatus 58.7%, and Leporinus obtusidens 53.1% (Chiari and Sodré, 2001); Astyanax altiparanae 78.41% (Leuzzi et al, 2004), Astyanax aff. bimaculatus 85.71% (Pamponet et al 2008), Pimelodus maculatus 50.1-60.94% (Almeida et al, 2003), and Steindachnerina insculpta 76.6% (Oliveira et al, 2002). By comparison, we foundP values of 82.0% to 30.5%, and H E levels of 0.312 to 0.122 in the five species studied here.…”

“…In neotropical fish populations fragmented by dams, there is a tendency towards changes in genetic structure when gene flow is disrupted. Significant genetic structure differences were found between populations of Pimelodus maculatus fragmented by dams in Paranapanema (Almeida et al, 2003), suggesting that this fragmentation has increased the rate of differentiation, which was initially caused by the existence of several natural waterfalls. Pamponet et al (2008) also found significant genetic structure differences between populations of Astyanax aff.…”

Genetic variability in four fish species (Pimelodus maculatus, Prochilodus lineatus, Salminus brasiliensis and Steindachneridion scripta) from Uruguay River basin

“…(Lacépède,1803), order Siluriformes, family Pimelodidae. Almeida et al (2003) performed studies in the P. maculatus population structure for the Tietê and Paranapanema Rivers and obtained genetic identity values around 0.96 for the Tietê and 0.91 for the Paranapanema River. These values were similar to those reported by Thorpe and Solé-Cava (1994), who found that 98% of the populations of the same species showed a genetic identity higher than 0.85.…”

“…Informations derived from molecular genetic techniques shall contribute significantly for the preservation of aquatic genetic resources and sustainable development (Carvalho, 1993;Chiari, 1999;Martins et al, 2003;Almeida et al, 2003). The RAPD procedure (Randomly Amplified Polymorphic DNA) has been instrumental to understand the genetic variability of fish populations (Bielawski and Pumo, 1997;Caccone et al, 1997;Callejas and Ochando, 1998;Dergam et al, 1998;Nadig et al, 1998;Liu et al, 1999;Prioli et al, 2002;Shikano and Taniguchi, 2002;Almeida et al, 2003;Bártfai et al, 2003;Hatanaka and Galetti Jr, 2003). This technique consists of amplification by PCR (Polymerase Chain Reaction) of random segments of genomic DNA using a single short primer of arbitrary sequence.…”