Paracentric Inversions Differentiate the Conservative Karyotypes in Two <b><i>Centropomus</i></b> Species (Teleostei: Centropomidae)

Abstract

Centropomus is the sole genus of the Centropomidae family (Teleostei), comprising 12 species widely distributed throughout the Western Atlantic and Eastern Pacific, with 6 of them occurring in the Western Atlantic in extensive sympatry. Their life history and phylogenetic relationships are well characterized; however, aspects of chromosomal evolution are still unknown. Here, cytogenetic analyses of 2 Centropomus species of great economic value (C. undecimalis and C. mexicanus) were performed using conventional (Giemsa, Ag-NOR, and fluorochrome staining, C- and replication banding) and molecular (chromosomal mapping of 18S and 5S rDNA, H2A-H2B and H3 hisDNA, and (TTAGGG)_n repeats) approaches. The karyotypes of both species were composed of 48 solely acrocentric chromosomes (2n = 48; FN = 48), but the single ribosomal site was located in varying positions in the long arms of the second largest chromosome pair. Replication bands were generally similar, although conspicuous differences were observed in some chromosome regions. In both species, the histone H3 genes were located on 3 apparently homeologous chromosome pairs, but the exact position of these clusters differed slightly. Interspecific hisDNA and rDNA site displacements can indicate the occurrence of multiple paracentric inversions during the evolutionary diversification of the Centropomus genomes. Although the karyotypes remained similar in both species, our data demonstrate an unsuspected microstructural reorganization between them, driven most likely by a series of paracentric inversions.

High Genetic Diversity despite Conserved Karyotype Organization in the Giant Trahiras from Genus Hoplias (Characiformes, Erythrinidae)

“…Several migratory fish families usually show conserved karyotypes concerning the 2n number and chromosomal macrostructure [19,43,44]. Despite this, microstructural and genetic changes may act as significant evolutionary factors, creating probable post-zygotic barriers as documented, for example, in Centropomus species [45]. Instead, the conservative chromosomal macrostructure of the H. lacerdae group is not maintained in the level of internal chromosomal characteristics.…”

Cytogenetics of the small-sized fish, Copeina guttata (Characiformes, Lebiasinidae): Novel insights into the karyotype differentiation of the family

“…In this context, the contribution of the cytogenetic studies to the knowledge of biodiversity and evolution of the Neotropical fishes is remarkable, providing useful taxonomic and evolutionary data (reviewed in [8]). Additionally, methodological advances in molecular cytogenetics, namely diverse variants of fluorescence in situ hybridization (FISH), allow to decipher karyotype/genome evolution among related species, including the degree of preserved conserved synteny and the characterization of structural and functional organization of genomes [9–20]. These approaches already helped to document cryptic species diversification [21–29] as well as to track remarkable karyotype stability [30,31], the response of the genome dynamics to environmental cues [32] or its correlation with geographic distribution [33].…”

Research Article The unusual high number of chromosomes signals rare multiple fission events in the Polynemidae (Carangaria, Teleostei)

“…Among Carangaria several families, like Centropomidae, Carangidae, Sphyraenidae, Coryphaenidae, Toxotidae, and Rachycentridae, have karyotypes mainly composed of 2n=48 chromosomes (Accioly et al, 2012;Costa et al, 2015;Soares et al, 2017;Supiwong et al, 2017;Borges et al, 2019;Motta-Neto et al, 2019), while Pleuronectiformes (mainly Pleuronectodei), have chromosome numbers ranging from 2n=26 to 2n=48 (Azevedo et al, 2007;Arai, 2011). Most of the karyotype variations are due to pericentric inversions and Robertsonian translocations, which promote an increase of the NF (number of chromosome arms) and reduction of the diploid number, as well as increasing polymorphisms in a species, providing variation for natural selection and can even lead to speciation.…”

“…Assuming 2n=48 chromosomes as the basal condition for Polynemidae, we can estimate that at least five fission events have occurred during the karyotype evolution of P. virginicus and P. oligodon, thus resulting in their peculiar high diploid number and four microchromosome pairs. These small kind of chromosomes are also very uncommon in Carangaria species, which usually present a symmetrical arrangement, showing a gradual variation in size between the largest and the smallest chromosomes in karyotypes (Molina et al, 2014;Costa et al, 2016;Borges et al, 2019).…”