title: Comparative application of direct sequencing, PCR-RFLP, and cytogenetic markers in the genetic characterization of Pimelodus (Siluriformes: Pimelodidae) species: possible implications for fish conservation.
abstract: Pimelodus (Pimelodidae) is a genus comprising a group of South American species with complex taxonomic relationships. Cytogenetics, polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP), and sequencing data of mitochondrial genes were analyzed to characterize 4 Pimelodus species: P. fur, P. heraldoi, P. maculatus, and Pimelodus sp. All populations presented 2n=56 chromosomes and distinct karyotypic formulae. The heterochromatin distribution pattern and the number and location of 5S and 18S rDNA sites are discussed. The application of PCR-RFLP markers and sequencing of mitochondrial DNA genes provided species-specific haplotypes, which allowed us to differentiate the species studied. The mitochondrial gene sequences presented nucleotide mutations in the restriction sites and throughout the sequences, and they were mostly related to synonymous substitutions in the coded proteins; however, they did not affect the protein and its function. Comparing the data obtained using these 3 methodologies, the existence of a species complex in P. maculatus along the basins studied might be inferred, showing that cytogenetics is an important tool in studies focusing on the conservation or management of both natural and captive populations of these fishes.
authors.affiliation: Departamento de Ciências Biológicas, Universidade Estadual do Sudoeste da Bahia, Jequié, BA, Brasil milena_fro@hotmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Ferreira
authors.affiliation: Departamento de Genética e Biologia Evolutiva, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: K C O
authors.initials: KC
authors.lastname: Bressane
authors.affiliation: Departamento de Genética e Biologia Evolutiva, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: A R C
authors.initials: AR
authors.lastname: Moresco
authors.affiliation: Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brasil.
authors.forename: O
authors.initials: O
authors.lastname: Moreira-Filho
authors.affiliation: Departamento de Genética e Biologia Evolutiva, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: L F
authors.initials: LF
authors.lastname: Almeida-Toledo
authors.affiliation: Departamento de Ciências Biológicas, Universidade Estadual do Sudoeste da Bahia, Jequié, BA, Brasil.
authors.forename: C
authors.initials: C
authors.lastname: Garcia
mesh_terms: D019943:Amino Acid Substitution; D054458:Amplified Fragment Length Polymorphism Analysis / Q000379:methods*; D000818:Animals; D002397:Catfishes / Q000145:classification / Q000235:genetics*; D020732:Cytogenetic Analysis / Q000379:methods*; D004272:DNA, Mitochondrial / Q000032:analysis; D029941:Fish Proteins / Q000235:genetics*; D005819:Genetic Markers; D059785:Karyotype; D017422:Sequence Analysis, DNA / Q000379:methods*
chemical_list: D004272:DNA, Mitochondrial; D029941:Fish Proteins; D005819:Genetic Markers