title: Karyotypic Evolution and Chromosomal Organization of Repetitive DNA Sequences in Species of Panaque, Panaqolus, and Scobinancistrus (Siluriformes and Loricariidae) from the Amazon Basin.
abstract: Loricariidae family comprises the greatest variability of Neotropical catfish species, with more than 800 valid species. This family shows significant chromosomal diversity. Mapping of repetitive DNA sequences can be very useful in exploring such diversity, especially among groups that appear to share a preserved karyotypic macrostructure. We describe the karyotypes of Panaque armbrusteri and Panaqolus sp., as assessed using classical cytogenetic methods. Moreover, we offer a map of their repetitive sequences, including 18S and 5S ribosomal DNAs, the Rex1 and Rex3 retrotransposons, and the Tc1-mariner transposon in P. armbrusteri, Panaqolus sp., Scobinancistrus aureatus, and Scobinancistrus pariolispos. Those species share chromosome numbers of 2n = 52, but are divergent in their chromosome structures and the distributions of their repetitive DNA sequences. In situ hybridization with 18S and 5S rDNA probes confirms chromosome location in different pairs; in Panaqolus sp. these sites are in synteny. This multigene family organization can be explained by the occurrence of chromosome rearrangements, and possible events, such as transposition and unequal crossing-over. Rex1 and Rex3 retrotransposons and the Tc1-mariner transposon appeared predominantly dispersed and in small clusters in some chromosome regions. These data emphasize the importance of repetitive sequences in promoting the karyotypic evolution of these species.
authors.affiliation: 1 Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará , Belém, Brazil .
authors.forename: Thayana
authors.initials: T
authors.lastname: Ayres-Alves
authors.affiliation: 2 Laboratório Genômica Integrativa, Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista , Botucatu, Brazil .
authors.forename: Adauto Lima
authors.initials: AL
authors.lastname: Cardoso
authors.affiliation: 1 Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará , Belém, Brazil .
authors.forename: Cleusa Yoshiko
authors.initials: CY
authors.lastname: Nagamachi
authors.affiliation: 3 Faculdade de Ciências Biológicas, Universidade Federal do Pará , Altamira, Brazil .
authors.forename: Leandro Melo de
authors.initials: LM
authors.lastname: Sousa
authors.affiliation: 1 Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará , Belém, Brazil .
authors.forename: Julio Cesar
authors.initials: JC
authors.lastname: Pieczarka
authors.affiliation: 1 Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará , Belém, Brazil .
authors.forename: Renata Coelho Rodrigues
authors.initials: RCR
authors.lastname: Noronha
mesh_terms: D000818:Animals; D001938:Brazil; D002397:Catfishes / Q000145:classification* / Q000235:genetics*; D002874:Chromosome Mapping; D004275:DNA, Ribosomal; D019143:Evolution, Molecular; D014644:Genetic Variation; D007621:Karyotyping / Q000662:veterinary; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012341:RNA, Ribosomal, 5S / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D018626:Retroelements
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012341:RNA, Ribosomal, 5S; D018626:Retroelements
keywords: Ancistrini; chromosomal diversity; fish mapping; repetitive sequences; retrotransposons; transposons