title: Physical mapping of 18S and 5S genes in pelagic species of the genera Caranx and Carangoides (Carangidae).
abstract: In Carangidae, Caranx is taxonomically controversial because of slight morphological differences among species, as well as because of its relationship with the genus Carangoides. Cytogenetic data has contributed to taxonomic and phylogenetic classification for some groups of fish. In this study, we examined the chromosomes of Caranx latus, Caranx lugubris, and Carangoides bartholomaei using classical methods, including conventional staining, C-banding, silver staining for nuclear organizer regions, base-specific fluorochrome, and 18S and 5S ribosomal sequence mapping using in situ hybridization. These 3 species showed chromosome numbers of 2n = 48, simple nuclear organizer regions (pair 1), and mainly centromeric heterochomatin. However, C. latus (NF = 50) and C. bartholomaei (NF = 50) showed a structurally conserved karyotype compared with C. lugubris (NF = 54), with a larger number of 2-armed chromosomes. The richness of GC-positive heterochromatic segments and sites in 5S rDNA in specific locations compared to the other 2 species reinforce the higher evolutionary dynamism in C. lugubris. Cytogenetic aspects shared between C. latus and C. bartholomaei confirm the remarkable phylogenetic proximity between these genera.
authors.affiliation: Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil.
authors.forename: U P
authors.initials: UP
authors.lastname: Jacobina
authors.affiliation: Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brasil.
authors.forename: L A C
authors.initials: LA
authors.lastname: Bertollo
authors.affiliation: Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brasil.
authors.forename: M
authors.initials: M
authors.lastname: Bello Cioffi
authors.affiliation: Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil molinawf@yahoo.com.br.
authors.forename: W F
authors.initials: WF
authors.lastname: Molina
mesh_terms: D000818:Animals; D001938:Brazil; D004275:DNA, Ribosomal / Q000235:genetics*; D017753:Ecosystem; D005399:Fishes / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D020161:Physical Chromosome Mapping / Q000379:methods*; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal