RAPD markers indicate the occurrence of structured populations in a migratory freshwater fish species

Abstract

Many factors have contributed to the destruction of fish habitats. Hydroelectric dams, water pollution and other environmental changes have resulted in the eradication of natural stocks. The aim of this study was to detect the genetic variation in Prochilodus marggravii from three collection sites in the area of influence of the Três Marias dam (MG) on the São Francisco river (Brazil), using the RAPD technique. The results obtained revealed that the fish in the downstream region nearest the dam have a higher similarity coefficient than those from the other sampling sites that may be related to differences in environmental characteristics in these regions. Additionaly, significant differences in the band frequencies were observed from one collection site to another. These both findings suggest the occurrence of a structured population and have important implications for the conservation of the genetic variability of distinct natural P. marggravii stocks.

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

“…Several studies have shown variations in genetic structure in neotropical fish populations due to isolation by distance in non-migratory species (Leuzzi et al, 2004;Sofia et al, 2006;Pamponet et al, 2008) or by formation of demes influenced by biological factors in species with a migratory habit (Wasko and Galetti Jr., 2002;Hatanaka and Galetti Jr., 2003). In neotropical fish populations fragmented by dams, there is a tendency towards changes in genetic structure when gene flow is disrupted.…”

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

“…According to Sivasundar et al (2001), Prochilodus are known for their high swimming capacity and their ability to migrate upstream and even overcoming rapids and falls. The knowledge regarding the Prochilodus population genetics is still scanty (Hatanaka and Galetti Jr, 2003). Genetic variability of P. lineatus captured in three regions of the Paraná River basin was evaluated by isoenzyme patterns (Revaldaves et al, 1997).…”

“…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.…”

Genetic evidence of population structuring in the neotropical freshwater fish Brycon hilarii (Valenciennes, 1850)

“…RAPD markers (Williams et al, 1990;Welsh and McClelland, 1990) have been widely employed in fish studies involving the identification of species and hybrids (Barman et al, 2003), as well as the construction of linkage maps (Khoo et al, 2003), inquiries related to aquaculture (Wasko et al, 2004), and the detection of the genetic structure of natural populations (Wasko and Galetti, 2002;Hatanaka and Galetti, 2003;Hassanien et al, 2004). The success of this methodology is due to the fact that it is capable of revealing a high degree of polymorphism and is very useful when there is no information on the genome of the investigated species.…”