title: Genomic Organization of Repetitive DNA Elements and Its Implications for the Chromosomal Evolution of Channid Fishes (Actinopterygii, Perciformes).
abstract: Channid fishes, commonly referred to as "snakeheads", are currently very important in Asian fishery and aquaculture due to the substantial decline in natural populations because of overexploitation. A large degree of chromosomal variation has been found in this family, mainly through the use of conventional cytogenetic investigations. In this study, we analyzed the karyotype structure and the distribution of 7 repetitive DNA sequences in several Channa species from different Thailand river basins. The aim of this study was to investigate the chromosomal differentiation among species and populations to improve upon the knowledge of its biodiversity and evolutionary history. Rearrangements, such as pericentric inversions, fusions and polyploidization, appear to be important events during the karyotypic evolution of this genus, resulting in the chromosomal diversity observed among the distinct species and even among populations of the same species. In addition, such variability is also increased by the genomic dynamism of repetitive elements, particularly by the differential distribution and accumulation of rDNA sequences on chromosomes. This marked diversity is likely linked to the lifestyle of the snakehead fishes and their population fragmentation, as already identified for other fish species. The karyotypic features highlight the biodiversity of the channid fishes and justify a taxonomic revision of the genus Channa, as well as of the Channidae family as a whole, as some nominal species may actually constitute species complexes.
authors.affiliation: Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
authors.forename: Marcelo de Bello
authors.initials: Mde B
authors.lastname: Cioffi
authors.affiliation: Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
authors.forename: Luiz Antonio Carlos
authors.initials: LA
authors.lastname: Bertollo
authors.affiliation: Franklin College of Arts and Sciences, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Mateo Andres
authors.initials: MA
authors.lastname: Villa
authors.affiliation: Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
authors.forename: Ezequiel Aguiar
authors.initials: EA
authors.lastname: de Oliveira
authors.affiliation: Department of Biology, Faculty of Science, Khon Kaen University, Muang District, Khon Kaen, Thailand.
authors.forename: Alongklod
authors.initials: A
authors.lastname: Tanomtong
authors.affiliation: Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
authors.forename: Cassia Fernanda
authors.initials: CF
authors.lastname: Yano
authors.affiliation: Faculty of applied science and engineering, Khon Kaen University, Nong Kai Campus, Muang, Nong Kai, 43000, Thailand.
authors.forename: Weerayuth
authors.initials: W
authors.lastname: Supiwong
authors.affiliation: Department of Biology, Faculty of Science, Khon Kaen University, Muang District, Khon Kaen, Thailand; Genetics and Environmental Toxicology Research Group, Khon Kaen University, Muang District, Khon Kaen, Thailand.
authors.forename: Arunrat
authors.initials: A
authors.lastname: Chaveerach
mesh_terms: D000818:Animals; D002875:Chromosomes / Q000235:genetics*; D019143:Evolution, Molecular; D016678:Genome; D010473:Perciformes / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid